Cartridges: Accuracy Secrets of the .30-06 - Part 3


Accuracy Secrets of the .30-06 - Part 3
by Germán A. Salazar

Having discussed barrel and chamber reamer choices in Part 1 and a few specific accuracy loads in Part 2, we now move into the final installment of this short series and we'll discuss some reloading tools and techniques for accurate loading of the .30-06. Obviously, good reloading practices are applicable to any cartridge and it isn't my intention to make this an article on how to reload; the purpose of this is to highlight things that are either unique to the .30-06 or of particular importance on the .30-06. I will assume that the reader has a solid knowledge of reloading generally and accuracy reloading specifically, and accordingly, will skip or gloss over many of the basic items that are common to all cartridges.

Brass
One of the great virtues of the .30-06 is the huge variety of brass available for it. One of the real curses of the .30-06 is the huge variety of brass available for it! Huh? Well, it's kind of fun to see all the different headstamps and to try new types of brass, but it can absolutely drive you mad trying to maintain a consistent level of performance. I have .30-06 cases that weigh 176 gr. and I have others that weigh over 200 gr. - and plenty that are in between. Clearly, the load has to be adjusted as you switch from one type of brass to another. Then there's neck thickness; it varies as much as case weight and can also cause problems.
1. Brand Selection. The first recommendation regarding brass is to standardize on one brand, or at most two brands, of brass. There will still be some lot to lot variance, but it won't be too much. If I were going to the store tomorrow to buy all new .30-06 brass, it would be Lapua or Norma if the budget allowed it and Winchester as a great alternative. Those choices are based on my observations of brass quality as discussed in item 3 below. However, if you love another brand, or have it already, that's fine and you'll develop your loads around that type.

2. Neck Turning. Because of all the variability in brass, I turn all case necks to the same dimension: 0.0125" thickness. That means I take a lot off of a Lapua case and a little off of a Winchester and kind of in between for a Lake City. But, and this is the critical point, doing so allows me to use the same sizing die setup and obtain the same neck tension on the bullet with any brand of case. Click here for earlier neck turning article.



NECO Audette case tool
3. Case Indexing. The .30-06 case is fairly long, which means that it will more easily develop a thick side and a thin side during the drawing process by which the case is made. The more draws the manufacturer uses in forming the case from the brass cup, the more uniform it will be, but the higher the manufacturing cost will be. Any significant variance in case wall thickness will definitely cause a degradation of accuracy and will make it difficult to get a truly concentric alignment of case and bullet because the case will quickly develop a banana shape. I use the NECO made version of the Creighton Audette tool to check the cases, mark them on the thin side and then insert them into the chamber with the index mark always in the same orientation. Since I began doing this with the .30-06, I've seen a distinct increase in my X count and maybe a couple of points in the aggregate. The effect was not as noticeable with short cases like the 6BR which aren't stretched as much during manufacturing and thus maintain more even wall thickness. To learn more about the process, read this earlier article.
I think if you do those three things, you've addressed the main concerns with .30-06 brass. Any other form of brass sorting or preparation that you believe to be worthwhile is fine, although I've never been one to weight-sort brass or deburr flash holes. If it makes you feel good, do it, if it doesn't, that's OK as long as you took care of the three big items.

Resizing
1. Sizing Die. I have six or seven .30-06 sizing dies including bushing dies, body dies, neck dies, and conventional full-length dies. However, almost 100% of the time, I use a standard Redding full-length sizing die that I bought used for $5 from a fellow shooter at the range; I even got a seater for that price. Why? Simply because it is a great match for my chamber. Once I saw how well it sized, I adjusted my neck turning dimension so that this die would give me the neck tension I want without oversizing. When you can just barely feel the expander ball gliding over the inside of the case neck, you've got it right.
The great body fit with the standard Redding die is nice, but the Redding bushing dies also have a great body fit and you can adjust the neck to any tension, right? Yes, but there's one more reason to use a standard die over a bushing die: concentricity. A once-piece die that doesn't overwork the neck will almost always give you better concentricity than a bushing die because the bushing has to have some radial clearance for ease of insertion and that thousandth or two of clearance will degrade concentricity. Allowing the bushing to float a tiny bit by not clamping the top down tightly (just back it off a tiny little bit) helps, but a one-piece die is still better.


2. Headspace. The longer a case is, and the more tapered it is, the more it will grow each time you resize it; and the more it grows, the sooner you will run into a case head separation. With modern case designs such as the .308 or the 6BR both of which have moderately sharp shoulder angles and straight bodies, you need to set the shoulder back 0.002" or so in order to ensure easy bolt operation and to avoid galling the locking lugs and seats. The .30-06, however, with its mild shoulder angle of 17.5 degrees and it's long, tapered body, works just fine with a 0.000" setback. This isn't the same as neck sizing, because you're still sizing the whole body. However, if you work carefully, you can set your die for 0.000" to 0.001" setback, extend case life a little (I get 11 to 13 firings from most of my brass) and maintain reliable functioning.








Tooling
We've covered all of the basics and there isn't really any tool that's unique to the .30-06, but some take on extra importance with this cartridge.

Forster Headspace Gauge
A good headspace gauge that you can use quickly and easily is essential. I have two that I rely on: a Mo's thimble type gauge ((203) 775-1013) and a Forster case gauge (the Wilson is virtually identical). They do the same thing: give me a shoulder setback reading and allow me to check trim length.













Mo's Headspace Gauge























The NECO Audette tool is critical to me. Without it, I know that my scores would be a little lower and I don't have any room to give up points or X's. I get a lot of peace of mind from checking and indexing my brass with the NECO tool.

Giraud Case Trimmer






















The case trimmer is another big item. With a 6BR you might trim every seven or eight firings because that short, straight case seems to never grow - that isn't so with a .30-06! I use a Giraud case trimmer and trim the cases on every firing. These cases grow quite a bit and I don't take any chances with safety. A manual trimmer takes a long time and I would be tempted to skip this step now and then without the Giraud, so this is a convenience item, but really a safety item.


Conclusion
Our objective is to create ammunition capable of consistent high scores at distances from 300 to 1000 yards under match conditions. That means it might be 40 degrees, or 110 degrees; it might be a calm day or a windy day, it might be raining, it might be blowing dust - in any of these conditions, if the ammunition causes rifle functioning problems, the match is already lost. Careful attention to the tips in this series should allow you to load .30-06 ammunition fully capable of winning matches at any distance against competitors of skill similar to your own.


 

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