Basics: Neck Tension

Neck Tension, Bushing Dies and Other Reloading Mysteries
by Germán A. Salazar

Neck tension is a frequently discussed topic among handloaders as you step past the basic level - and for good reason, neck tension is an important element in producing the most accurate loads possible and keeping your brass functional for a longer time. 

Fundamentally, neck tension is a term used to describe the interference fit between the inside diameter of the neck and the outside diameter of the bullet.  In short, we're going to seat a bullet into a neck that is smaller than the bullet and this can only be accomplished because the brass will yield under pressure and the inside diameter of the case neck will open to accept the bullet.  However, because brass is a fairly live and springy metal, the neck tries to return to its former size, thus applying tension to the bullet.  While neck tension can be measured in units of force necessary to push the bullet in, it is more common to describe it in the linear dimension terms of neck's outside diameter before and after seating the bullet.

As I just said, we use the neck's outside diameter as our basic reference despite the fact that it is the inside diameter that we are actually interested in.  That's because most reloaders don't have a set of gauge pins or tiny inside micrometers to take direct measurements of the inside diameter of case necks, accordingly, the outside diameter serves as a useful proxy as long as we know how thick the necks are.  Calipers cannot be used to measure inside diameter (a common question from reloaders) because the blades are not in line with each other so you are not measuring a true diameter.  Neither can calipers be used to measure neck thickness with any degree of precision because there are slight irregularities in the neck, especially at the mouth, that will affect the reading.


A tubing micrometer, which has a fixed anvil with a ball tip is the most accurate tool for measuring neck thickness.  As you'll note in the picture above, I've created a small step for the case to rest on, this ensures that I'm measuring all necks at the same distance from the case mouth.  While I could have gotten by without the step for .30-06 cases such as that in the picture, other cartridges with shorter necks couldn't be measured consistently without it.  The step is simply a small piece of leather taped to the micrometer to elevate the case a bit, nothing fancy.

As the micrometer indicates, this piece of brass is 0.0125" thick at the point measured.  That is the dimension to which I normally turn my .30-06 brass.  When turning, I measure each piece of brass at three locations along its circumference, but that's not relevant here.  If your brass isn't neck turned, take a few measurements on a few piece of brass in order to get a solid idea of average neck thickness.  You will find some inconsistencies, and that's life with unturned brass, just be aware of them and determine the average thickness.


A conventional sizing die establishes neck tension regardless of neck thickness by simply sizing the neck down more than it needs to be and then expanding it from the inside with the expander.  While this works well for general reloading purposes, it tends to overwork the brass leading to early neck splits and it doesn't allow you to fine tune your loads by varying neck tension.  Redding, Hornady, Forster and perhaps others make sizing dies with interchangeable bushings to allow you to size the necks down just enough for your particular lot of brass and desired neck tension.  The cutaway die shown above has an expander in place, but for most bolt-action use, the expander is removed and replaced with a simple threaded retainer for the decapping pin.

The cutaway die gives you a good look at how the bushing (the gold colored piece) is held in the die by the top plug.  While you might see or hear references to the bushing "floating" in reality, it is held in a close tolerance hole and is not free to move.  In the Redding Competition Neck Die with the micrometer top, the bushing can be allowed to move upward, thus limiting how far down the neck it sizes, but there is no practical reason for a Highpower shooter to do this.  The Type S dies, like the one shown here, don't have that level of adjustment - and that's no loss.

The pointer in the photo above is indicating the junction of the bushing with the shoulder area of the die.  You will notice in your sized cases that there is a slight bulge right at this point.  That's because the bushing has a small bevel to allow the neck to enter without shaving brass, so the lowest portion of the neck which comes to rest in that bevel doesn't get sized as much.  The bulge will have no negative effect on accuracy or brass life.  However, if you plan to neck turn, then the cases should be sized with a conventional non-bushing die prior to the turning operation.  That's because the neck turner would cut the bulge off, thus dangerously weakening the necks at that point and perhaps leading to a neck separation upon firing.

Well, with that general discussion of dies and brass thickness out of the way, let's talk about how to set neck tension to your needs.

For the sake of having an example, we'll use a Lake City .30-06 case that has been neck turned to 0.0125" as shown above.  Let's do some quick math - if the neck wall thickness is 0.0125" then the total of both sides is 0.0125" x 2 = 0.0250".  Assuming that our bullet is 0.308" in diameter, then the loaded cartridge should have an outside neck diameter of 0.308" + 0.025" = 0.333".  So, if our final diameter will (hopefully) be 0.333" and we want to have 0.002" neck tension (a pretty standard amount), then we'll need to size our neck to 0.331" before seating the bullet.


So, we have our fired case and are ready to size it.  Why don't we just run it through a die with a 0.331" bushing and be done with it?  We've already determined that's the desired outside neck diameter before seating the bullet, right?  Well, in some cases, but not most, you can do that.  In order to make that determination, however, we need to do some measuring and checking.  As you can see above, the outside diameter of the fired case neck is 0.339".  Since it was fired in a chamber with a SAAMI standard chamber with a chamber neck diameter of 0.340", and brass tends to spring back a little after firing, that's exactly what we would expect to see.

Now for another bit of math - we need to take our case neck from 0.339" down to 0.331", a reduction of 0.008" in outside diameter; this is a fairly typical amount.  What I have found over the years, as have many other reloaders, is that when you use the bushing dies to size down more than 0.005" at a time, they really don't do a very good job.  The result tends to be poor concentricity of the sized neck to the body and an outside diameter that is smaller than the marked bushing size. In fact, the necks might tend to be somewhat funnel-shaped, leading to some real interesting neck tension situations.

The best approach is to limit your sizing to steps of no more than 0.005" each and to make multiple passes as needed - I've never seen a situation that required more than two passes, so don't panic.


The first step in my resizing process for this brass was to size it with a full-length Redding Type S bushing die with a 0.334" bushing.  That brought the neck's outside diameter to 0.334", just as the bushing is marked, and set the headspace to my specifications for this rifle (see the article on setting headspace if needed).


The next step is to size the brass in a Redding neck sizing die with a 0.331" bushing, and, as shown above, the outside neck diameter is indeed 0.331" after this step.  Had we gone straight to the 0.331" bushing, this wouldn't be the case at all.  While I use a neck die for the second pass, you could use the same full-length die as in the first pass, although you should be careful to ensure that you aren't setting the shoulder back more on the second pass.  In reality, it's a lot easier to switch to a neck die for the second pass.  UPDATE: I have found that concentricity is slightly better if the first pass is with the neck die and the second pass with the full-length die.  Click here to see article on two-steo sizing with bushing dies.

As I mentioned before, brass is springy and these bushings take that into account.  However, as brass hardens a bit after repeated firing/sizing cycles, it may lose some spring and you may have to use a different bushing to get back to the desired outside diameter.  Don't worry, trust your measurements and give the brass what it needs in order to end up at the dimension you need.


Now that the neck is properly sized, let's have a look at the bullet.  Actually, this should have been done when we were measuring neck wall thickness before doing all the math, but since Sierra is pretty consistent, I left it until now.  In reality, there are better ways of measuring bullet diameter than calipers, but this isn't terribly critical, a few ten-thousandths difference here isn't what we're worried about, we want to make sure this is a 0.308" bullet, not a 0.309" like the Lapua D46, for instance (if it were a 0.309" we would have selected a different final bushing).  So, as the photo shows, this is a 0.308" bullet and our math is probably correct.


The payoff: here's the outside diameter of the finished cartridge and it is, of course, 0.333", meaning we have 0.002" neck tension because the finish sized case neck measured 0.331" before seating the bullet.  Now, we can use different final bushings to experiment with varying levels of neck tension and attempt to gauge its effect on accuracy.  If you're shooting a well chambered bolt action rifle and don't care to experiment too much, 0.002" neck tension will be a good place to set up your dies.

As a final note, I happen to know that the chamber neck diameter in the rifle is 0.340" since I own the reamer and have the print (yes, there can be tiny variance on that number).  However, the fact that the fired brass measured 0.339" is also a very good indicator, since 0.001" springback is about right in this size range.  So, with a 0.340" neck and a 0.333" loaded round, we have 0.007" clearance, a very safe amount for a Highpower rifle that gets used in very dusty conditions.  While we can get away with a bit less clearance, there's nothing wrong with this much for our use, brass will last through a lot of reloadings and accuracy will not be impaired.

Related Article:
Two-Step Sizing and Concentricity


Update - July 2, 2010

People frequently as "How much neck tension should I use?"  I think the following reponse from Paul the moderator at http://www.accurateshooter.com/ is about as good a response as I've seen on that topic.

There is no "best" -- some guns/cartridges work well with .001 neck tension, some others need more... maybe a lot more.



But here's a suggestion that may help put things in perspective. Think in terms of overall bullet "grip" instead of just bushing size.


Bullet grip is affected by many things, such as:


1. Neck-wall thickness


2. Amount of bearing surface (shank) in the neck


3. Surface condition inside of neck (carbon can act as a lubricant; ultrasonic cleaning makes necks "grabby")


4. The springiness of the brass (which is related to degree of work-hardening; # of firings; time between annealings)


5. Time during which the loaded round has sat prior to firing


--and there are others...


You can do this simple experiment. Seat a boattail bullet in your sized neck with .150" of bearing surface (shank) in the neck. Now remove the bullet with an impact hammer. Next, take another identical bullet and seat it with .300" of bearing surface in another sized case (same nominal tension). You'll find the deeper-seated bullet is gripped much harder.


I have also found that thinner necks, particularly the very thin necks used by short-range benchresters, require more sizing to give equivalent "grip". Again, do your own experiment. Seat a bullet in a case turned to .008 neckwall thickness and sized down .003. Now compare that to a case with .014 neckwall thickness and sized down .001. You may find that the bullet in the thin necks actually pulls out easier, though it supposedly has more "neck tension" based on bushing size.


This use of the term "neck tension" when we are really only describing the amount of neck diameter reduction with a die/bushing is really kind of inaccurate.


We don't have any easy way to measure "true" neck tension on a bullet.


My point here is that it is overly simplistic to ask: should I load with .001" tension or .003". In reality, an .001" reduction on a thick neck might provide as much or MORE "grip" on a long bullet than an .003" reduction on a very thin-walled case on a short shank.


What I think this means... and this is only a theory... is that I suspect the guys using .001" "tension" on no-turn brass may be a lot closer to the guys using .003" "tension" on turned necks than either group may realize.


This doesn't really provide any answers. You have to go out and test empirically to see what works, in YOUR rifle, with YOUR bullets and powder. And you may have to change the nominal tension setting (i.e. bushing size) as your brass work-hardens or IF YOU CHANGE SEATING DEPTHS.


All I'm saying is that the nominal bushing size is not really a satisfactory indicator of the true amount of neck grip on a bullet, or the force required for release. TRUE GRIP () is a much more complicated phenomenon, one that is affected by numerous factors, some of which are very hard to quantify.

Basics: Seating Depth

Checking Seating Depth
by: Germán A. Salazar

Our club has many members who are relatively new to the area of precision reloading for rifles; accordingly, I will ocassionally present a small feature on some aspects of reloading that will benefit those members.  The previous topic on headspace was one such article, here is another.

Determining exactly how long a specific bullet may be seated in the case before it touches the rifling is a simple, though important, process calling for a few tools and a delicate touch.  Once you have determined this dimension, you can then vary it in an effort to extract the maximum accuracy from your rifle.  While that tuning process will be a topic for another day, a few recommendations about seating depth will be at the end of this article.  First, let's see how we determine the basic dimension.


As with any mechanical process, you'll need some tools.  For this job, I use the Hornady OAL gauge (formerly Stoney Point), the Sinclair hex nut comparator, a good dial caliper and a 1/4" x 36" wood dowel (not shown).  In addition to the basic tools, you'll need bullets from the specific lot to be loaded and the appropriate Hornady modified case for the cartridge you are working with.  The rifle's barrel should be clean for this process as any fouling tends to cause erratic readings.


Begin by threading the case onto the tool, it should be snug, but just by hand.  Retract the inner rod by loosening the lock screw and insert a bullet into the case.


Remove the bolt and insert the tool with the bullet from the rear.


Now comes the step where you'll need a delicate touch.  Push forward on the rod with the heel of your hand while pushing forward on the tool with your thumb and forefinger.  You should feel the case seating firmly in the chamber.  Then, as you push the rod forward, you will feel some resistance to the bullet's movement as it enters the throat and then you will feel it come to a stop as it contacts the rifling.  Try this a few times when you are first using the tool; depending on the dimensions of your chamber, the resistance in the throat may be somewhat high and can fool you. 

Assuming that you've now developed a good touch for when the bullet hits the rifling, bring the bullet to the touching point, then lock the thumbscrew while maintaining forward pressure on the rod and the tool as described above.  Pull the tool back slightly, insert the wood dowel into the muzzle and tap the bullet free from the rifling (it tends to stick slightly).  You may remove the bullet and tool together or separately, it makes no difference.

Now, making sure not to allow the thumbscrew to loosen, insert the bullet back into the case. 


If you don't yet have the Sincalir hex nut comparator (or something similar) you can measure the OAL (bullet tip to cartridge base) and you will have an approximate dimension at which your bullet will touch the rifling.  I say approximate, because with modern match bullets, which are almost all hollow-point types, the tips vary somewhat due to the jagged nature of the jacket when it is drawn to a point.  The bullets I used for this illustration are full metal jacket (closed point) and are a bit more consistent in their dimensions.  If you aren't using a comparator, you should take the reading with several bullets and determine an average value.


If you have the comparator (highly recommended) then slip the hex nut comparator onto the bullet (in the appropriately marked hole for your caliber) and measure the resulting overall length.  The comparator rests on the point at which the bullet reaches full diameter and thus where it contacts the rifling.  This allows for a very precise reading and one that is not affected by irregularities of the tip.

I usually denote this dimension as COAL (comparator overall length) in my reloading notes.  Obviously this is a longer dimension that a plain OAL (bullet tip to cartridge base) but the actual value of the number is meaningless except for your reference.  If the comparator were larger, for instance, the dimension would be larger, but you would still know what's right with that bullet for that rifle.

Now that you have the dimension at which the bullet will touch the rifling, what do you do next?  You can now experiment with seating depth based on whether the bullet is jumping to the rifling or is jammed into the rifling.  Adjust your seating die and check finished rounds with the comparator until you reach the desired COAL.

A good place to begin (and frankly to stay unless you're already at the Master level in NRA Highpower) is to jump 0.020" for conventional tangent ogive type bullets such as the Sierra MatchKing line or Berger's new designs and to jam 0.015" for VLD type bullets such as Berger VLD, Hornady AMAX, JLK VLD, and others of the secant ogive design. 

There are slight variations in any lot of bullets, so when you check your finished rounds you will see some variance in the COAL - don't worry about it too much.  The reason we selected the jump and jam figures given is because they allow for some slight variance and still maintain the basic concept of jump or jam.  If you were to set the jump for 0.003" for instance, then a slight variance might have some bullets jumping, some right on the lands, and some actually jammed a few thousandths.  By sticking to 0.020" jump or 0.015" jam, those same slight variances will have minimal effect - imperceptible for the Highpower shooter anyway.

There you have it - quick, simple and better scores are sure to follow.  This is an important part of handloading for your rifle, rather than simply producing generic reloads.

History: The Ben Avery Shooting Facility

The article below is now over 10 years old but still stands as the most complete description of the events surrounding the formation of what we now know as the Ben Avery Shooting Facility. -GAS-


The Ben Avery Shooting Facility: A 40 Year Tribute
by Don Turner, Chief Rangemaster, Ben Avery Shooting Facility
May 11, 1998





Ben Avery's spirit as an active outdoors writer and environmental champion flows over the Sonoran Desert and lingers on a 1650 acre parcel of land dedicated to his ideals. Ben had a vision of a place where men, women and their children could enjoy a sport called "shooting." This place would be safe and clean and provide opportunities for Arizona citizens and their guests to practice their marksmanship skills for hunting and competition, and learn safe firearms handling. A place that would help take the shooters out of the desert, a place that would encourage youngsters to learn the traditions of their heritage and be open to all citizens at a reasonable fee. Ben's vision included a place where shooters from all over the world could come and enjoy Arizona's weather, hospitality, and compete for local and world titles.


In addition to his ideas for a range, and as a hunter and fisherman and a lover of the Arizona outdoors, Ben was an early champion of an independent Game and Fish Commission, through his efforts (and many others) the public voted to establish the current Game and Fish Commission and Department. This association with the Commission is what led Ben to select the Arizona Game and Fish Commission as cooperative owners of the Black Canyon Range.  Working with his friends and fellow visionaries, Ben succeeded in developing the Black Canyon Shooting Range. Perhaps the best way to tell this story is in Ben's own words.

The following is extracted from a letter Ben wrote to the "Members of the Maricopa County Parks and Recreation Board" sometime in 1983:


I make a plea against raising the range fee at Black Canyon Shooting Range from $2 to $3, and urge Maricopa County to adopt a realistic policy on subsidizing the range.  In support of this plea I would like to give you some historical background and make a few points.  First, a shooting range is not a park in the ordinary sense, but I believe we have pioneered very successfully at Black Canyon to prove that a good shooting range can be created as a park recreation area with widespread benefits to the community.


First some history. The idea for this range germinated in the minds of myself, Glenn C. Taylor, then secretary of the Phoenix Rod and Gun Club, and Jim Beaman, then president of the Phoenix Sportmen's Association about 1950. Beaman felt we should have a sort of sportsmen's country club, Taylor and I were very concerned about a place to hold competitive rifle and pistol matches and to provide a safe place for the general public to shoot. At that time America and Arizona was being flooded by cheap foreign and U.S. World War II surplus rifles and pistols and ammunition. The desert was becoming a battleground of whizzing bullets every weekend, and some of this wasn't far from the city. The area west of Seventh Street across from Tapatico Cliffs Resort resembled a Korean battlefield. Sheriff Cal Boies said his office was swamped with calls from irate citizens. There was talk of all kinds of restrictive laws.  Because of my knowledge of land matters, the laws, and the kind of area needed, by more or less mutual consent I became the coordinator of this effort to find and develop a range.

Howard Pyle was governor and Roger Ernst was State Land Commissioner in 1953. Roger agreed to go with me and take his land status maps. We spent more than a week looking at sites, hoping to find public land that would be easy to acquire and easy to develop as close to possible to Phoenix.  We finally settled on two sites. No. 1 was 1,300 acres of state land just north of Happy Valley Road and west of the Black Canyon Highway. The No. 2 choice was the present site of Black Canyon, five miles further out.


Roger agreed to support efforts to obtain the land which would require:
1. Getting a state agency to apply for a lease on the land.
2. Exercising a law authorizing an agency of the state to take an existing lease away from someone else for a public purpose.



We had to look to the Arizona Game and Fish Department for a state agency and that required getting the legislature to amend the game and fish law to authorize it to acquire land for shooting ranges and to lease or sublease such lands or even operate such ranges. In due time I prepared a bill and got it introduced in the legislature. The lessees of the Happy Valley land immediately launched a lobby against that bill, even setting up a table just outside the door of the House of Representatives which was actively manned by these
prominent lessees who were holding the land for future development. I was able to win House approval, however, with only 8 dissenting votes, and the Senate passed the measure without trouble.


The fight didn't end there, however. The governor's approval was needed for the institutional taking, and the
lessees won over Governor McFarland who had succeeded Pyle and we could not get him to act. Our plans sat on dead center until Paul Fannin succeeded McFarland. Paul recognized the need and promised his support. In the meantime, through his efforts, I met with the lessees of the Happy Valley land and I had talked to Rancher Bob Lockett who held leases on the present Black Canyon site. Lockett offered to give us his leases if we chose that site, and the Happy Valley lessees, which included TKG Construction Co.,
offered to help us with a $5,000 donation of construction work if we would pick our No. 2 site. We did not need the opposition of our neighbors, so we agreed to go five miles further out.


Fannin, Adjutant General Clyde Wilson and the new land commissioner, Obed Lassen met with me at the present site early in 1959 and all gave strong approval. Bob Lockett and O.N. Arrington of the Game and Fish Department met a few days later and agreed on terms of Lockett's release of his lease on the land. Meantime I obtained an agreement from the Maricopa County Board of Supervisors and Kenneth J. Smithee, County Parks Director, to operate the range as a county park, and the Park Department's landscape architect and I located the section corners, and surveyed the range, laying out the various facilities we would need.


It was too late for Maricopa County to include the range operation in its budget for 1959, so I obtained a $5,000 loan from Valley National Bank and made an appeal through my newspaper column for donations so range construction could begin, using the Marine Corps Reserve Engineering Unit and its earth-moving equipment. I received more than $3.000 in donations within a few weeks, and set up the Arizona State Rifle and Pistol Association Range Fund, which we are still using to support the range. At that time Glenn Taylor was president of the association and I was secretary-treasurer.

Retired Marine M/Sgt. Frank Cannon, who had operated the Camp Matthews Marine Range in San Diego during the war, volunteered to begin supervising the range immediately, and sportsmen began using the area to sight in their rifles almost immediately. We started moving dirt and building the first canopy in November, 1959.


Maricopa County took over operation of the range July 1, 1960, and reimbursed us for the canopy so we could pay off the Valley Bank loan.  I continued to coordinate range construction with volunteer labor, donated materials such as concrete block, sand and gravel, telephone poles, concrete, even the steel water tank. The Game and Fish Department drilled both wells, provided pipe for the water system, which was installed by volunteer workers.


It is my belief that no park in this state has ever received as much in the way of volunteer labor and donated construction and materials as Black Canyon, and that continues even today, because a shooting range is different from an ordinary park.  From the beginning those of us who build Black Canyon wanted to make sure it was operated in a safe manner to fulfill its mission of providing a safe place for the general public to shoot.



In 1967, the NRA (National Rifle Association) sought our help as a place to hold the 1970 World Shooting
Championships.  After two years of hard work by many residents of this county, particularly Tom Wardell and the employees of the Parks Department, the world shooting championships were held in October 1970, bringing shooters from 52 nations to Phoenix. Eighteen world records were equalled or broken during those matches. The NRA spent $600,000 putting them on, and the Chamber of Commerce estimated they brought $6.5 million into the business community.


When we started developing the International shooting facilities at Black Canyon, it became necessary to purchase the land, and funds were appropriated from the Game and Fish Fund to make that purchase over a five-year period for $330.000.  Black Canyon Range firearms safety training facilities have been build by Arizona Game and Fish Department and some 5,000 youngsters and adults are trained each year as part of a statewide program that has virtually eliminated firearms hunting fatalities in this state.  I ask your forgiveness for this lengthy statement, I have compiled it in the hope that each of you would benefit by having a sort of a history of Black Canyon Shooting Range to give you a better understanding of its mission and the reason for its existence.


Sincerely,
Ben Avery



Since its inception, Ben's vision has continued to grow and thrive. Over 40 years many things have been added and changed to the range. The Black Canyon Range was managed by a "committee of three" which included the Director of the Maricopa County Parks and Recreation Department, the President of the Arizona State Rifle and Pistol Association, the Director of the Arizona Game and Fish Department. Under this arrangement, the County Parks Department managed, operated and maintained the Range. The Arizona State Rifle and Pistol Association provided daily on the ground assistance, and the Arizona Game and Fish Department owned the property and provided financial and heavy equipment resources as necessary. Under Maricopa County's management, the ranges continued to serve the public at a high level of service.

In 1992, in honor of Ben Avery, the Black Canyon Range was renamed the Ben Avery Range. In 1995, during negotiations for the renewal of the 25 year lease to operate the range, Maricopa County decided that it would no longer manage of the Range. In August of 1995, the Arizona Game and Fish Department began operating the range in hopes of obtaining a new manager of the property. During this transition period, the Game and Fish Commission began to receive intense public pressure requesting that the Game and Fish
Department continue as the direct operators and managers of the property, a petition over 3,000 signatures was submitted to the Commission in favor of this desire. In order to demonstrate the complexity and variety of the Range, the Department renamed it the Ben Avery Shooting Facility.


Beginning fiscal year July 1996, the Department began a new project. Named "Statewide Shooting Ranges Project," the Department established a project which consisted of five separate tasks. Statewide shooting ranges administration, Ben Avery administration, Ben Avery operations, Ben Avery maintenance, and Ben Avery redevelopment. This project now expands across the state to provide services to other shooting ranges which includes the administration of a newly created $50,000 shooting ranges grant program. The new budgets were designed to set up staffing, equipment, operations, maintenance, and redevelopment projects for the facility. Project funding is from Federal-Aid to Wildlife Restoration, (these fees are collected from purchases of firearms and ammunition and archery equipment), and hunting and fishing license sales.

The Ben Avery Shooting Facility is housed on 1650 acres of the Sonoran Desert, located at the northwest corner of I-17 and the Carefree Highway (State Route 74, exit 223). Its hours of operation are seasonal with summer hours from 7am to 7pm Wednesday through Sunday. The facility which hosted over 72,000 shooter days last year, consists of six major areas: the Main Range, the Main Office, Shooters Campground, Specialty Ranges, Archery Ranges, and the Clay Target Center.

Main Range This is the primary public range for the facility, and includes pistol and rifle shooting with distances of 5, 10, 15, 25, 50, 100, and 200 yards. It has been redesigned to modern outdoor range standards. which includes a 53 point covered firing line with concrete shooting benches. Shooters pay a $4.00 daily range fee and are supervised by Game and Fish Rangemasters, or volunteer Line Safety Officers. This range received 58% of the total shooting days last fiscal year. All persons wishing to shoot, use the archery range, or director's of competitive events must check in with the Rangemaster at the Main Range.

Thursday nights is league night. The smallbore range is the site for the NRA Junior Rifle Program, sponsored by the Arizona State Rifle and Pistol Association. There is also a Ladies League on the Main Range, Bullseye Pistol at 2700 range, and combat pistol hosted by the Cactus Match League at the practical pistol ranges.

Main Range Office Located just west of the Main Range, this office is the administrative site for the statewide shooting ranges project, and for the operation of the Ben Avery Shooting Facility. The facility still hosts a large number of Hunter Education field days and has set aside an area just for Hunter Education. You may visit or call the office at (623) 582-8313 to obtain information about upcoming events, shooting classes, or to reserve a campsite, or just to say hello. The facility staff of seven employees is supplemented with extensive volunteer service. Last fiscal year volunteers donated 18,000 hours of labor (this equates to 9 full time employees).

Shooter's Campground Located due south of the Activity Center, Shooter's Campground has 99 campsites. Fifty-five of these have water and electrical hookups (20 amp service). A dump station is provided for guests. Because of the distance from motels, this area was developed to support the various events held during the 1970 World Shoot. In keeping with this intent, and as a reflection of the volume of shooters who visit the range with recreational vehicles, this campground is restricted to use by shooters only. Due to its popularity, guests are asked to call ahead for reservations. Fees are $12 per night for hooks ups and $8 per night without. There are three rest rooms with showers for guest use. A fourteen day stay limitation is enforced.

Specialty Ranges These ranges were designed and are used for competitive events. As they are not supervised by the Rangemasters, these ranges are used by Ben Avery User Groups who must provide their own insurance and safety officers. When the Department took over the facility in 1995, there were 65 of these groups. This has now grown to 125. Every shooting event that you might wish to compete in is shot at the facility. We have ranges which include indoor air gun, smallbore rifle, bullseye pistol, international pistol, running boar, high power rifle (up to 1,000 yards), High power and smallbore Rifle Silhouette, Benchrest,
Practical Pistol, Silhouette Pistol, three training buildings, and a central Activity Center. In addition, 16 commercial operators provide firearms training courses including the popular concealed weapon classes.

Archery Ranges We just received the National Field Archery Association's "five star" rating for these ranges. The archery range actually consists of a clubhouse with bathrooms, a playground, a picnic area, five field courses, a target course, and a FITA range. This is a beautiful area and is the site for many competitive field course events including the popular 3-D shoots.

Clay Target Center  The Clay Target Center is one of the finest in the world. It features 17 trap ranges, 9 skeet ranges, a beautiful and challenging sporting clays course, 5 stand, and ZZ Bird ranges. It also has a pro shop where one can rent shotguns and purchase ammunition and other clay shooting items.

Contrary to the current social belief concerning shooting sports, the Ben Avery Shooting Facility is expanding in user days and the Department, in cooperation with the Arizona State Rifle and Pistol Association, and the Ben Avery Range Association, has embarked upon an aggressive redevelopment project. From a general
clean up, to painting, to new ranges the facility is being given a face lift. Future public projects include a community outreach program with on site shooting clinics and off site activities; development of the Hunter Education Area; promotion of junior shooting programs; increased participation of women shooters and
many, many more activities.

If you're a shooter and haven't been to the facility, there's just no excuse. Drop by and "give us your best shot." It's a great place and you won't regret it. If you're not a shooter, drop in anyway and see what's going on. Your visit will put a bigger smile on Ben's face.



The statistical information here is frm the 1996-97 time frame, much has changed since then, mostly in the form of more ranges and improvements and more users. -GAS- 

Reloading: IMR 4320

IMR 4320 - The Forgotten Powder
by: Germán A. Salazar

If you are relatively new to reloading, you may not have even heard of IMR 4320.  It is probably the least popular powder in the IMR line and yet, it has some great applications.  IMR 4320 falls right between 4895 and 4064 on the burn rate scale for most cartridges - in other words, right where Varget falls.  Yet, despite having a very useful burn rate, 4320 has languished for decades while newer powders of similar burn rate have gained in popularity.

I have an older lot of it (1998) which I use in the .308 with 185 grain bullets and it works very nicely for 500 and 600 yard matches with a mild charge producing velocitied in the low 2600 range.  I also use it with 168 gr. and 175 gr. bullets in the .30-06 for 200 and 300 yard loads.  However, I was interested in seeing what current production IMR 4320 would do in the .308 with the 155 gr. Palma bullets.  My interest was sparked by the obvious fact that Varget and H4895 have been very hard to get lately while 4320 sits on the shelves.  Lester Bruno told me recently that he sent a batch of IMR 4320 back to Hodgdon in the middle of the powder shortage because it doesn't sell.

A look at the Sierra manual shows that their maximum load with the 155 is 47.2 gr. and gives 2900 fps in their 24" test barrel.  This was encouraging, since our 30" Palma barrels will definitely add to that - and we'll need a bit more for 1000 yards.  I got a new 8 lb. jug of IMR 4320, 2009 production, and tested it in the .308 with 155 Sierras.

My first step was to load a few rounds with some moderate charges just to get a feel for the powder.  I loaded and shot 44.0, 45.0 and 46.0 at 200 yards.  You should note that 4320 has very small granules and throws very consistently from the powder measure - in fact it is very much like Reloder 15 in granule size - so for those who prefer to throw, rather than weigh, charges it's a good choice. 

The 44.0 load wasn't too promising, the 45.0 looked fantastic and the 46.0 was also very good.  I judged these on the amount of vertical dispersion in the groups, all of which were fired prone, iron sights from my RPA Quadlock Palma rifle.  Apart from the powder, the rest of the components were: Winchester brass, PMC primers (Russian), and moly-coated Sierra 155 Palma bullets.  All loads in this article were fired with moly-coated bullets and should be reduced by at least 1.0 gr. for bare bullets.

The second stage of the project was to chronograph some loads and shoot on paper with anything that looked interesting (I don't shoot on paper while chronographing).  Unfortunately, I only had a 100 yard range available for this part.  Below is a summary of the chrono testing.  The first three charges were 8 shots each, the remainder 5 shots each.  This was simply to get an idea of how 4320 responds to increases and what sort of velocity range it would give.  Standard Deviation, which is a great measure of a load's uniformity is much more meaningful with 10 to 20 shots per load, so I don't place a huge value on these numbers.  However, the MV showed a fairly normal progression as the charge weight increased.

44.0 gr. - Avg. MV 2762 fps; ES 54; SD 19
45.0 gr. - Avg. MV 2844 fps; ES 37; SD 11
46.0 gr. - Avg. MV 2911 fps; ES 45; SD 13
46.5 gr. - Avg. MV 2952 fps; ES 53; SD 23
47.0 gr. - Avg. MV 2990 fps; ES 18; SD 08
47.5 gr. - Avg. MV 3011 fps; ES 22; SD 08  ***  Exceeds published maximum load.
48.0 gr. - Avg. MV 3048 fps; ES 31; SD 12  *** Exceeds published maximum load.

I stopped at 48.0 grains because that was more than enough velocity for shooting at 1000 yards, the SD was beginning to increase and the powder was now up to the base of the neck (much lower than Varget or 4895 are for comparable velocities); 47.0 gr. is just below the base of the neck.  Also, since the Sierra book shows a maximum load of 47.2 for bare bullets I figured 48.0 was pretty close to maximum pressure with moly although neither the bolt opening, nor extraction, nor the primers showed any signs of undue pressure.

I loaded 13 rounds of the 47.0 gr. load, used three to sight in and fired 10 for record at 100 yards on the NRA 100 yard Smallbore target (2" 10 ring, 1" X ring).  I shot a 100-9X with the only 10 being a high shot that I called high just as I fired it.

My usual .308 Palma load fires the 155's at 3030 fps with an SD in the low single digits.  I've often thought I'm pushing things too hard and plan to back that load down a bit this coming season.  However, it's a very accurate load, so that's not something that I'll do without some testing at 1000 yards.  With that load as a benchmark, I plan to shoot the IMR 4320 loads tomorrow (Sunday Oct. 11) at a 500 yard match.  I'll begin with the current load (which uses H4895) then switch to the 45.0 IMR 4320 load and then the 47.0 IMR 4320 load.  I will clean the barrel a bit after the first string to avoid the possibility of the H4895 fouling making the first few shots of 4320 behave erratically.  I can't say that it would, but I can't say that it won't, so I'll clean.

More tomorrow...

Sunday, October 10, 2009.
I fired the 500 yard prone match today using my RPA Quadlock Palma rifle, Warner sights, Krieger 1:13" twist barrel.  Conditions were calm initially but very windy and switchy by the third string.  Temperature went from high 60's to the low 80's.  I decided to shoot the 4320 loads first and leave the 4895 for last, and that was a fortunate decision as things turned out.  As in the chrono tests, all loads were with moly-coated Sierra 155 Palma bullets, Winchester brass and PMC primers.  Powder charges should be reduced at least 1.0 gr. for bare bullets. 

The load with 45.0 gr. of IMR 4320 gave me a 199-12X with the single 9 being a high shot just off the 10 ring line at 12:00.  Of the 20 shots, three were above the X ring and three below it, and I made a few small elevation changes during the string.  Overall, I would rate that load as good, very useable for the intended purpose of 500 or 600 yard shooting (it's 2844 fps) but no better than my 4895 load for that purpose. 

Next I fired the 47.0 load and that was an eye opener.  The score was 200-15X in conditions that were windier than those in which the first load was fired.  Elevation was noticeably tighter and shots were exactly on call.  This load gives 2990 fps, so it has real potential as a Palma load.  While no 500 yard test can ensure results at 1000, given the MV and reasonably low SD of this load as well as the good performance at 500, I won't hesitate to shoot it at 1000 at the first opportunity.

My current Palma load of 45.5 H4895 was the last one fired and conditions were downright tricky by then.  I shot a 196-12X with the 9's coming on hard and fast reversals that just caught me while I was aiming.  The X count and the good elevation that the load held were enough for me to see that it was working well - the 9's were just the breaks of the game.

Overall, I'm very satisfied with what I've seen in these past few days from IMR 4320 and plan to shoot it in some of our upcoming Palma and 1000 yard matches with the 155's.  It appears to be a very useful alternative to some of the harder to get powders.

Update - December 11, 2009The load is working extremely well at 1000 yards.  In the recently completed Arizona Palma State Championship, several high placing competitors were using the 4320 load.  In one case, we loaded ammo for a national team member at my house the night before the match began.  He was at Bruno's buying all the 4320 he could find after that day's shooting.  We got sub X-ring elevation at 1000 yards from several rifles, and that's all I'm looking for in a Palma load.
 

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