Lapua Small Primer .308 Brass
by Germán A. Salazar
by Germán A. Salazar
We've all seen the recent reports about the new Lapua small primer .308 brass. The old saying "You can't know where you're going if you don't know where you've been" is very applicable here; let's review the history of small primer .308 brass.
My first reaction to the announcement of the new Lapua brass was "old news" as this brass does not appear to be different in any material way from the Remington small primer .308 brass which I've worked with quite a bit in the past. I still have several hundred of the Remington and I don't use it because I've never found a performance improvement with it at long-range despite significant amounts of testing. When Remington made their small primer brass, it was intended to be reformed into .22 BR, 6 BR and 7 BR, in fact some of the ones I have are even headstamped .22 BR. The small primer is adequate and correct for the BR capacity but not necessarily for the full-length .308. Remington did not intend for this brass to be used for .308 shooting.
If you've read my primer articles (small primer article, large primer article), you will recall that the fundamental conclusion was that the best primer was generally the primer which had the lowest flash level and produced the lowest muzzle velocity. All of this, of course, assumes that the primer provides enough energy for consistent and reliable ignition. Primers are an excellent example of what I like to call the Goldilocks Conundrum: finding the "just right" point along an imprecisely defined continuum. In this case, the continuum of ignition energy to be applied to the powder charge.
Simply stated, the small primer in the .308 case is at the low end of acceptable ignition under ideal conditions - and conditions are often not ideal. As ambient temperature drops and especially if ignition systems are modified (uselessly, I might add) with lighter firing pins, ignition reliability declines. A system which is marginally acceptable under ideal conditions will then begin to produce hangfires and misfires. In many cases, when shooters used the Remington small primer cases as a full-length .308, this is exactly what happened. Heavier powder charges and slow-burning powders further add to the difficulty of ensuring reliable ignition. With the typical Palma load of 46 grains of Varget, a moderately slow powder, I will venture to say that many small primers will be inadequate to ensure adequate ignition under all environmental conditions.
Before the arrival of the Russian primers, most large rifle primers were more powerful that was necessary for a .308 case and a reduction of primer energy could, in some circumstances be beneficial. However, most of the shooters who used the Remington small primer brass, after experiencing some ignition trouble, switched to the Remington 7 1/2 (if they kept using the brass at all). The irony of this is that the Remington 7 1/2 primer produces more flash than almost any large rifle primer; yes, it is a small primer that produces more flash than most large primers! Go back to the primer articles and look at the pictures. In essence, by switching to the Remington 7 1/2, these shooters were returning to a large primer level of ignition energy. Today, we have an excellent small flash large primer - the Russian - which has, in my considered opinion, eliminated the problem of too much flash in the .308 case without introducing the problems of too little flash. It is the Goldilocks primer for the .308 and similar size cases: just right.
The only truly successful use of the Remington small primer brass which I am aware of was by Bob Jensen who used it for 300 yard rapid fire loads. Bob had a fairly light load for rapid fire, knows primers well enough to have selected a reliable and mild primer and shot the brass only in the summer months. The small primer kept ignition consistent with his mild load and he fired many very high scores with the small primer brass - in 300 yard rapid fire. Tellingly, however, Bob did not use the brass for his 600 or 1000 yard .308 ammunition at the time and he certainly didn't specifiy it when he was tasked with loading 98,000 rounds of .308 long-range ammunition for the US Army Marksmanship Unit or when he loaded 300,000 rounds for the 1992 Palma match. Those long-range rounds all used regular Winchester large primer .308 brass. Now we are being told that small primer .308 brass is the latest, greatest thing for long-range shooting...
Lester Bruno gave me 24 pieces of the new Lapua to try out and I intend to give them a good trial. Given that Lester had a grand total of 29 pieces on hand, this was a very generous offer and I appreciate it! Selecting the correct primer for them is really the biggest part of the testing because the entire purpose of the project is the use a primer which is milder than a good large rifle primer while still producing enough energy to reliably ignite the charge. As an initial matter, I suspect that the Russian small rifle primer will be too mild and the Remington 7 1/2 too harsh (it always is). I have some Federal 205 Magnum (yes, 205 Magnum) primers which have always tested consistently and are relatively mild, though not as mild as the Russians. My concern over using these for the testing is that they are no longer available so the test becomes useless. The CCI BR4 primer is just a tiny bit stronger than the Russian, and it contains aluminum particles which disperse through the powder charge to aid ignition. The lack of those particles is one of the Russian primer's great aids to consistency, but in this case, they might be of some value. The standard Federal 205 might also be a useful choice, though the lot to lot variance on these is more than other brands.
Later today I will post some basic weights and measures on the new brass. This will include weight and variance, neck thickness and variance, case body wall variance (as measured with the Audette tool). I will shoot them this weekend at 1000 yards, side by side with my normal large primer brass and report back as well. At some point, hopefully soon, I'll do some chronograph testing of the brass with a few different primers, but I don't know how soon I'll be able to do that. In any event, I'll post my findings as they develop.
Case Weight and Variance
I weighed 20 of the cases on my Ohaus Navigator scale, the lightest weighs 173.7 gr. and the heaviest weighs 174.6. All but the one lightest case are between 174.0 and 174.6, for my purposes, this is very uniform brass in terms of weight. I wouldn't bother to sort it on this basis. Modern Winchester brass typically weighs 155 grains, so this brass is distinctly heavier (although the same as Lapua's large primer .308 brass) and I will have to adjust my load somewhat to compensate for the reduced internal capacity. I'll check capacity before loading and decide on the appropriate adjustment.
Neck Thickness and Variance
I measured case neck thickness with an electronic Mitutoyo ball micrometer. Case necks were relatively uniform, with most cases exhibiting just over 0.001" variance in thickness around their circumference. Typical thickness was 0.0142" to 0.0152" per case with some going a few tenths thicker or thinner. Since I neck turn all my brass, this doesn't especially bother me, but I expected the variance to be somewhat lower. Maybe my expectations were too high.
Case Body Thickness Variance
Using the Audette tool, I checked the cases for variance in case wall thickness 0.250" up from the inside of the base. Frankly, I was very disappointed with this result. The cases average 0.003" variance which is right on my reject point for this measurement which I consider this to be the most important measure of case uniformity. Only four of the twenty cases measured were under 0.003" variance and more than that were over 0.003". My Winchester .308 brass rarely hits 0.003" with most falling between 0.001" and 0.002"; even the Winchester and Lapua .30-06 brass is usually in the 0.002" range. Why this brass is distinctly worse, I don't know as shorter brass is theoretically easier to draw uniformly.
As I mentioned earlier, I need to turn the necks on this brass to fit my chamber which has a 0.336" neck diameter. I turn all my .308 brass to 0.0125" neck thickness which produces a loaded neck diameter of 0.333" for 0.003" diametral clearance. Turning this much off the necks is best done in two passes. Tonight I turned them to 0.0136", that killed the charge on my little Craftsman power screwdriver. I'll make the second pass tomorrow and then load them for the weekend.
Neck turning is now complete, all are at 0.0125" to 0.0127". That was a lot of brass to remove!
Flash Hole Size
As I was looking at the brass, I noticed the flash holes look small, real small. The decapping pin from the Redding .308 die measures 0.062" diameter and will not go through the flash hole. The decapping pin from the Redding 6BR die measures 0.057" and will go through the flash holes. Looks like I'll be swapping decapping assemblies from the 6BR die to the .308 die in order to reload these cases. Not a major hassle, but something to be aware of before reloading or you'll get the decapping pin stuck in the flash hole. This problem was common with 6BR brass when it first came out, until Lapua and Norma slightly enlarged the flash hole. Sinclair makes a little reamer just for that purpose; I'll see if it opens the flash holes just enough for the 0.062" pin, that would solve the problem.
I neck sized the brass to 0.331", primed with CCI BR4 primers and loaded with my normal Palma load, slightly reduced for the heavier brass. I had to remove the decapping pin from the neck die and will have to decap with a Wilson PPC punch, but that'll be allright for a small quantity like this. Of course I had to try one case with the decapping pin in place and predictably, it got stuck in the flash hole and had to be driven out. Don't try it, the decapping pin is no substitute for the flash hole reamer. What is really needed, however, is for Lapua to actually drill the holes to 0.065" so that a 0.062" decapping pin will fit!
Shooting the new brass - finally!
Palma match in Phoenix today, so I took ammo loaded in the new brass as well as my normal load in Winchester brass. The plan was to shoot the Palma with the standard load and then to fire an extra 15 shot string at 1000 yards with the new brass. As things turned out, I was able to do exactly that and better yet, I was able to fire the two strings on consecutive relays after one of the shooters on my point dropped out.
Conditions were reasonably good, temperature around 65 degrees, good illumination on the targets despite a few clouds and wind in the 3 to 12 mph range. While the wind was more that we'd like to see for ammunition testing, it's fairly typical for our area and reflects the realistic conditions under which we shoot Palma and under which this brass will have to prove itself. I often had to make 3 moa to 6 moa corrections for consecutive shots as the wind velocity was changing quickly on both strings although it got a bit tougher with each relay.
I fired my first 1000 yard string on the second relay; this was with Winchester large primer brass and Russian primers, which gave me a 147-6X. The was the top score on that relay and only beaten overall by a 148-4X and a 148-2X fired on the first relay. My second string was with the Lapua small primer brass and CCI BR4 primers. I shot a 146-4X which was the highest score on the third relay (the last of the day and the trickiest). Both strings had comparable elevation dispersion and no elevation change was required on the sight between the two loads, so I must have made a reasonably accurate estimate of the powder charge change to keep velocity equal between the two types of brass.
My first impression, therefore, is that this was one heck of a lot of work for no noticeable improvement under typical Palma conditions. Elevation dispersion was the same and the scores were about the same. Increased risk of reduced ignition under adverse conditions for no performance gain under ideal conditions is a poor trade-off. I'll shoot this brass again at least once, but I don't see any magic - not that I expected any.
For detailed primer testing information, please see the articles linked below:
A Match Primer Study in the 6BR Cartridge
A Match Primer Study in the .30-06 Cartridge
Update, August 2 -2010
I found this posted on a forum today, no surprise...
Well finally got my hands on the new Palma brass with the small primer, what a dissapointment. Loaded my normal load of 44.6 of 2206H (H4895) using CCI450's and 155 HBC,I use these primers in my 6BR with no issues, loaded the first round and pulled the trigger "click" !!! oh well maybe I didn't put any powder in that one (came home pulled the bullet and found I had filled with powder !!) put the next round in and pulled the trigger click BANG !!! and hit 3.5moa low @ 600M, went back to the LR brass with the same batch of powder and all is good,temp was about 18 deg C.
Has anyone else had this problem ?? I have read that there was a velocity drop of 20-30 FPS but 3.5moa @ 600 is more than 20-30FPS and the click BANG is a worry, thought and advice welcomed.
Update, August 23, 2010
I shot the small primer brass for one string at 500 yards yesterday. First I shot a string with Winchester large primer brass, PMC (Russian) primers, scored a 200-16X in mild conditions. The next string with identical conditions, using the Lapua small primer brass yielded a 198-10X with double the elevation dispersion and two 9's which were completely off call. I used CCI BR4 primers with the Lapua brass and the powder charge was adjusted to match the MV of the Winchester brass.
Update, October 13, 2010
The following was posted by Kevin Thomas of Lapua on the forum at http://www.accurateshooter.com/ (underlining is ours) http://www.accurateshooter.com/forum/index.php/topic,3751998.0.html
[T]he flash holes on the new Palma SRP cases are indeed 1.5mm, as opposed to the more standard 2.0mm used on most of our other cases. We utilize the smaller (1.5mm) flash holes on a number of cases, all of which are primarily accuruacy oriented. The 220 Russian, 6mm BR and 6.5x47 are the others, with the 308 Palma being the latest. Yes, you will need to switch out your decapping pin in most 308 Win dies to avoid sticking a pin in the flash hole. Do apologize for the inconvenience here, but as has been pointed out, we were responding to customer's requests here, and it does indeed seem to work. There have also been several comments here about the potential reliability in cold weather, and we agree with those assesments. The cases were intended for competitive shooting, which is generally conducted in nice, warm, sunny weather (at least, that's the way I like it!). We discourage reloaders from using this brass for cold weather hunting, or heavy charges of slow burning, hard to ignite powders, because there is a real possibility of poor ignition, hangfires or outright failures to fire in such situations.
And another related quote from Kevin about the .308 small primer case:
...you're perfectly correct that this is pretty much the outer limit of what a small primer can reliably ignite. To that end, we're marketing this as a competitive case, and not recommending it fro many hunting applications. Extreme cold temps or harder to ignite charges of slow burning powders could be a problem here with hangfires or that sort of thing. However, with the normal powders used for competition (such as Varget) and the conditions competitions are normally held under, this is not a problem. Give them a try, and see if they don't help reduce the variables I've discussed here.
I don't want to give the impression that I'm gratuitously bashing the small primer case, however, I think it bears emphasizing that the small primer carries with it the potential for misfires or squib ignition which can cost you a match and I have found no overwhelming performance gain (none at all actually) to justify risking a match in this manner. This is simply another example of faddish trends and the prudent competitor would do well to stick to the well proven, time-tested large rifle case for the .308, whether Lapua or any other brand that you favor. - GAS -
I just saw the quote below on a forum and it really gave me a smile since I'm a big fan of Cheers. I try to be as honest and straightforward as I can on any evaluation, but I suppose we all have biases. In any event, this points to the possibility that the early batch of brass I got was not representative of current production in terms of wall thickness variance. - GAS - Here's the forum quote:
I think German is basing his experience on a bad lot of brass. He reported an AVERAGE of .003" wall thickness variation. Using my NECO and inspecting 100 cases, I found 2 with .0015" and those were the worst. The average for my batch was .0007".Related Article
German bags on these every chance he gets, but when he shot them the first time, I don't think he even worked up a load with them... new brass and new primers require at least a new load workup.
I am a huge fan of German's and am a religious reader of his blog, but he gave this brass short thrift. It reminds me of an old quote from Cheers, "I tried that positive thinking crap and I knew it wouldn't work and sure enough, it didn't."
Large Flash Hole vs. Small Flash Hole Test
A Savage Is Savaged!
by Germán A. Salazar
by Germán A. Salazar
These are the times that try men's souls...
Thomas Paine, of course, wrote those memorable words in 1776 to remind us of our duty to fight tyrrany. Today, we face many trials and equally, we must fight; we must resist the siren song of artificial optical enhancements, the lure of a well formed piece of glass, the temptation of magnification! No, not for us the easy path, we must be true to our history, true to the iron sights that made of us - iron men!
Sadly, tragically, one of our own has fallen and it is a macabre scene. Depicted below is the visual record of one man's fall from grace. This is not for the squeamish or the faint of heart - remove the women and children from the room, for these images, once viewed, will not soon be forgotten. We present this evidence, not to appeal to the prurient interest, but as an example of the terrible fate that can befall a seemingly normal man, an upright, well regarded member of the community, once he falls to the temptation. Hold fast men, for we must not allow another tragedy such as this!
It all began innocently enough - a new rifle arrives, normally a moment of joy, a cause for a gathering of friends and eager anticipation of joyous, sun drenched days on the range amidst the lizards, snakes, scorpions and spiders with whom we share the crust of this earth. The clues to the depredations to come were there to be seen, but who could have imagined it? Surely, that black box proudly proclaiming it's lurid contents was just a gag - it was, wasn't it?
The new member of the family was welcomed, no one suspecting the brutality that lay in wait. There she was, innocent, untried - her adjustable cheekpiece waiting to be nuzzled, her 3 way buttplate sashaying as she turned, her slender 30" barrel proudly jutting forth. Some might say she was just a Savage, but can that excuse the despicable acts that followed? Look carefully and you'll see the evil glint in her handler's eye, betraying his criminal intent; oh, the despair she might feel if only she could see!
And then it began - without a word, she was forced down, held against her will as the device, the "rail" as they call it, was attached to her proud topside. Were that it were but clamped on, but no, for the evil one then applied a heavy dose of epoxy to make sure that she could not be rescued, could not be returned to her former glory - his perfidy, her shame, were forevermore.
I ask you: what manner of man is it who could smile as he holds such an instrument of torture and degradation above the victim as she lies in the rack, wet with epoxy and quivering with fright of what surely is to come? A beast, I say to you, only a beast!
We are all men of the world here, but there are some things simply too gruesome, too contemptible to show. Out of a simple sense of decency we cannot show the horrid act itself. But here is the beast, with his accomplice reveling in the aftermath, holding the limp and defiled victim - now the slave of the glass demon. Light a candle, Lucy, another one is lost to the dark side.
Compounding the felony, the perpetrators turn their attention to other forms of mayhem. Not enough for them to leave the innocent Savage shattered, branded, hobbled, no, they seek to further terrorize the countryside as they coldly and callously throw fresh-faced Finnish brass and bullets into the Rube Goldberg "loading device". Do they intend to feed this Gatling gruel to the once proud Savage? Know they not, that the Rockchuck is its natural form of nutrition? Is there no end to the havoc these miscreants wreak upon our fair land? Though my heart be in pain as I view this foul den of iniquity, I must return to the words of Paine, who ended his famous appeal thusly:
"Look on this picture and weep over it! And if there yet remains one thoughtless wretch who believes it not, let him suffer it unlamented.
Western Shooters' Pet Loads for Long Range
by: Germán A. Salazar
It should go without saying by now that you should never take a load from a third party source - like this site - and just use it in your rifle without a workup from a lower level - that could be catastrophic. That goes double for the loads presented here because long-range loads are, by their very nature, on the upper end of the pressure spectrum for any given cartridge. When you also consider the variations in the actual burning rate of various powder lots, differences in barrel dimensions, differences in bullets, even of the same weight and make, it should be glaringly obvious that only a negligent fool would copy a load without working up. And you're no fool, right?
With that having been said, considered and taken to heart by all of you, let's have a look at Palma and other long-range loads and techniques from a number of our club members.
Tompkins .308Mid's load for the Palma rifle is a fairly standard one in some respects but not in others; let's have a look.
Brass: old Winchester .308, weighs 170 gr., same as Lapua in capacity.
Powder: Varget, 46.0 gr.
Primer: Russian LR Magnum
Bullet: Berger 155.5 gr. Fullbore
Average Muzzle Velocity: 2975 fps
Barrel: 0.2980" x 0.3075" with a 1:13" twist, 30" long.
Mid soft-seats all bullets, meaning they have very light case neck tension and are seated long in the case. This allows the bullet to slide back in the neck as it touches the rifling when the bolt closes; he says: " My chamber is my seating die." In order to get the neck tension just right for soft-seating, Mid turns the necks on his brass and sizes for light tension with a bushing die. Then, just before loading, he runs the case necks over an expander mandrel that gets the inside diameter exactly to his desired dimension. Mid commented that bushings and mandrels have to be carefully selected and sometimes changed, to get just the right neck tension on the bullet. As for other case preparation, Mid said: "It's a waste of time to do primer pocket and flash hole uniforming" but he checks cases on the Audette tool for case wall runout. In a final comment, Mid noted: "It's easy to go too hot on muzzle velocity; you can't see the difference in wind drift on the target from an extra 50 fps."
Tompkins 6.5-284Mid shoots a 6.5-284 for Any-Rifle matches; in fact he pioneered that cartridge for long-range shooting. "You can use either Winchester or Lapua brass, but you must match the reamer to the brass. You can shoot Winchester brass in a Lapua chamber (though not the opposite), but you'll get shorter brass life because the primer pockets will expand quicker due to the bigger chamber" says Mid. He goes on to say: "Winchester brass has to be necked down from .284" and you can get a donut at the base of the neck. Most people don't seat the bullet that deep so it doesn't make much difference." Mid also soft-seats in the 6.5-284 using the same process as described above for the .308. He mentioned that pre-loading for a number of rifles before going on a summer shooting tour as he does each year makes soft-seating the only way to conveniently ensure that bullet seating in relation to the rifling remains constant as the barrels erode during the course of a few thousand rounds fired.
Brass: Winchester .284W necked down
Powder: Hodgdon 4350
Primer: Russian LR Magnum
Bullet: 140 Berger or 142 Sierra
Average Muzzle Velocity: 2975 fps Berger, 3075 fps Sierra
Barrel: 1:8" twist, standard internal dimensions, 30" long.
Mid tells us that he is able to load one grain more of powder with the Sierra bullet than the Berger bullet before seeing pressure signs, thus the difference in muzzle velocity between the two.
Brass: Winchester .308
Powder: IMR 4895, 44.8 gr.
Primer: Federal 210M
Bullet: Sierra 155 (2155) 2.80" OAL
Average Muzzle Velocity: 2980 fps
Barrel: 0.300" x 0.308", 1:13" twist, 30" long
Jensen .30-338 MagnumDuring the 1960's, 1970's and 1980's, the .30-338 Magnum was the king of 1000 yard shooting. Well adapted to the available powders, particularly 4350, easy to make by necking down .338 Magnum brass (or necking up 7 mm Magnum brass), the .30-338 ruled the range. Bob's 1977 Wimbledon Cup winning load is a real classic for the .30-338, hard to improve on even 33 years later.
Brass: Winchester .338 Magnum, necked down to .30 caliber
Powder: IMR 4350, 65.0 gr.
Bullet: Sierra 190
Average Muzzle Velocity: never chronographed, Bob reports he didn't have a chrono back then.
Barrel: 0.300" x 0.308" 1:11" twist 28" long, Hart
Brass: Lapua, approx. 170 gr. case weight
Powder: Varget, 46.6 gr.
Primer: Russian LR
Bullet: Berger 155.5 gr. Fullbore or Sierra 155 (2156) (No preference) Bergers seated to jump 0.010", Sierras seated to jump 0.020"
Average Muzzle Velocity: 2985 fps
Barrel: 0.300" x 0.308", 1:13" twist, 30" long, Krieger or Hart, no preference
Like a lot of us, Allen shoots a few different cartridges in Any-Rifle matches, but he has had a lot of success with the 6.5-08 so we'll have him cover that one. Allen does the same brass and bullet inspection and preparation for the 6.5-08 as described for his .308 except that necks are turned 100% and to the thickness required to give 0.002" chamber neck clearance on a loaded round. This is pretty tight clearance and not recommended for the relatively new shooter. Whle Allen tried Remington .260 brass, he was unable to get a high enough percentage of it to pass the Audette inspection to make it worthwhile. Consequently, he uses Federal .308 brass necked down in two steps (7-08, then 6.5-08) and neck turned. He uses Federal because it checks well on the Audette test and he had a lot of it available. Allen said: "I have a lot of problems with donuts at the base of the neck with this one. I got a cutter and it barely touched the donut, then I got another cutter which turned out to be slightly larger (by coincidence) and it cuts them out but it's better to do it in two steps, using the smaller cutter first, then the larger one because it's too much to take out in one pass."
Brass: Federal .308 necked down and neck turned
Powder: H4350 41.6 gr.
Primer: Russian LR
Bullet: Sierra 142 seated to jump 0.020"
Average Muzzle Velocity: 2765 fps
Barrel: 1:8" twist, standard internal dimensions, 29" long, Krieger
Brass: WCC 60 or new Winchester (both weigh approx. 154 gr.), neck turned to 0.0125"
Powder: H4895 44.5 gr.
Primer: Russian LR
Bullet: Berger 175 BT, moly-coated, seated to jam 0.010"
Average Muzzle Velocity: 2835 fps
Barrel: 0.300" x 0.308", 1:11" twist, 29" long Krieger
As my friends know, I like shooting the .30-06 and find that it can be quite competitive at 1000 yards, even against all the sub-caliber wonder cartridges. Like the .308, I use a lot of different bullets, but I have a basic "go-to" load that works perfectly at any distance including 1000 yards; nothing magic, just good, solid components and careful assembly. I normally use Winchester brass which checks out very well on the Audette tool and reject anything over 0.003" case wall thickness variance, turn necks to 0.0125" and do no additional prep or sorting - really the same as my .308 brass. On both cartridges, I do my final sizing with a 0.331" bushing for 0.002" neck tension and trim on a Giraud trimmer as needed. Bullets are all moly-coated and pointed on the Whidden tool.
Brass: Winchester .30-06, neck turned to 0.0125"
Powder: H4350, 53.5 gr.
Primer: Russian LR
Bullet: Sierra 190, moly-coated, seated to jam 0.010"
Average Muzzle Velocity: 2800 fps
Barrel: 0.300" x 0.308", 1:11" twist, 28" long, Hart
The following is a question from a friend and my answer to him. I'm posting them here because it's a very good question for the newer Palma shooter and hopefully the answer will provide the information needed when making a decision about bullets and barrels. -GAS-
Palma Bullets and Barrels - A 2010 Overview
By: Germán A. Salazar
By: Germán A. Salazar
That's a good question that deserves some thought, more people should ask.
The 175 class of bullets is next and right there is my current favorite overall Palma bullet, the new Berger 175 BT. The 175 is a slightly lengthened version of the 155.5 Fullbore and has shot very well for me in both .308 and .30-06 in barrels with twist rates of 1:13", 1:12", 1:11" and 1:10" as I would expect a good bullet to do. The wind drift on the 175 is less than the 155.5 when both are loaded to the same pressure level (the MV will be lower, but if pressure is the same on two bullets of the same type, the heavier will drift less). I shot the 175 Berger in the recent Arizona Palma Championship and finished well with it. I use H4895 powder with it. I haven't shot the Sierra 175 in a long time and never in a Palma so I can't comment on it, but I suspect that it does not have the aerodynamic characteristics of the Berger. You can check into that by running some numbers on them at JBM Ballistics select the Litz data for each bullet from the bullet list (it'll be obvious when you're there).
The new 185 Berger has been winning a lot of Palma matches, and is the current choice of Bryan Litz who is certainly a top Palma shooter. It says a lot that this is the bullet Bryan chooses for his own shooting since he is Berger's ballistics chief. Mid Tompkins shoots it also and he's a pretty sharp guy as you probably know. Theoretically, based on drift, this is the best Palma bullet available today. I have a few boxes and have tried them but have always felt the 175's were shooting better for me. This may simply be a case of inadequate load development on my part and that would be perfectly understandable since I tend to put loads together with small variations and try them in matches more than doing a more formalized development program. Still, the 175's have come together quickly and shot great for me, but not the 185's.
I shoot the old Lapua 185 FMJ D46 bullet a lot because I have a ton of them. However, like the Sierra 2155, it's an outdated design and not worth buying now. Burning up an old stock is fine and I shoot them at all distances. Like the old Sierra, you have to crank the windage knob a bit extra with the D46, but I don't mind. They will shoot very well in almost any barrel regardless of wear, a very attractive feature!
The 190 Sierra is my standard bullet for .30 caliber shooting. While it isn't very high in BC and it has a long bearing surface which keeps MV down a bit, it is reliably accurate at all distances and will work with a normal .308 chamber, although a slightly longer throat is a good thing but not essential. With a new barrel, I generally evaluate it's potential with the 190 and then try other things if it looks good. If it won't shoot 190's well, chances are it isn't going to shoot well at all (assuming proper rate of twist). The Berger 190 VLD is another good 190, but the 185 BT has really superseded it.
I've shot the Berger 210 and other heavy bullets in .308 but will omit them from this discussion because you really need to have a dedicated barrel for them with a 1:10" twist and a long throat. They're interesting, but a specialized area.
Rate of twist is a more interesting question. As I mentioned earlier, slow twist barrels, on the ragged edge of stability, keep bullets of less than perfect construction flying slightly closer to the intended path. British shooters even liked 1:14" twist barrels for ball, again for that reason. We are shooting good bullets, so let's eliminate that consideration as we examine twist.
The rate of twist required to stabilize a bullet of a given caliber is directly proportional to its length. As bullets have become more streamlined for higher BC in any given weight category (as discussed above) they have gotten longer. Think about it a moment, the only way to increase the BC of a bullet at a given weight is to stretch the nose and maybe the boat tail to a more streamlined shape, thus lengthening it. That means that today's bullets generally should use a slightly faster twist than the old ones.
I consider a 1:12" to be the slowest desirable rate of twist for a Palma rifle today if one is not intent on shooting 155's. The 1:13" can shoot 175 and in some cases the 185 well, but it's easier to get them shooting from a faster twist. The 1:12" will shoot all of these perfectly well and in many cases the 190's as well, although that's not guaranteed.
The 1:11" twist is my general preference. It will handle all bullet weights with no concern. From a 155 to a 190, I never have to give rate of twist a second thought with a 1:11" and I can just conduct my load testing or match shooting with whatever bullet catches my eye that day (and I like to try a lot of different ones). Generally speaking, a 1:11" 0.300" x 0.308" barrel is my idea of a perfect .308 or .30-06 barrel.
The 1:10" barrel doesn't gain anything over the 1:11" for most uses because you need a long throat to shoot the 210 class bullets that the 1:10" allows you to shoot. That, of course, wipes out the barrel for light bullet use because you can't keep them in the case neck! My only 1:10" is on a .30-06 that I use for 210's on occasion - there's no good reason to use one for a general purpose .308.
What we need to talk about next is chamber reamers and they are a big topic unto themselves.