Neck Reaming vs. Turning...or Both?

[konrad]

Neck Reaming vs. Turning…or Both?

This will be my first endeavor with the 7 mm Remington Magnum cartridge. I am going to be launching projectiles from the Savage 11/111 Long Range Hunter (AccuTrigger, AccuStock and muzzle brake with 24 total inches of rifled barrel). My goal is to maximize the accuracy potential of this system by hand crafting ammunition of the most consistent that I can produce.

My questions are:

1. What method of addressing neck thickness/projectile gripping tension/concentricity is the most beneficial?

2. Should I be looking at outside neck turning or neck reaming?

3. How does one establish the correct thickness for the neck wall? What is the optimum dimension for this cartridge?

4. I anticipate using standard Redding dies and setting them so that only the neck is resized and the shoulder is never set back after the first firing. Should I instead be looking at a neck sizing only die? This will be the only platform in my battery of this caliber and so the product will never be used in another firearm.

5. What brand brass does one recommend? I was originally drawn to the Nosler offering but read some less than flattering reviews on the Midway USA website. Many others were comparing the Nosler brass to Norma very favorably???
I have never had good success with Remington reloading components or ammunition but have thoroughly enjoyed their firearm products.

6. Winchester Western brass is currently used in all of my long arms, pistols and revolvers. Should I go for WW?

[versifier]

Unless there is a serious issue with a particular lot of brass where one side of the neck is thicker than the other (in which case toss the lot) there is no need to be messing with the necks in a standard commercially cut chamber. The only time that case neck thickness is critical is when you have a custom match chamber where the chamber neck is at minimum dimension. Otherwise you are creating a situation where the neck gets overstretched as it expands and then is resized, overworking the brass and work hardening it making it brittle and requiring more frequent annealing to prevent neck splits. Outside turning can form a "donut" at the base of the neck, reaming does not necessarily even out an asymmetric neck and neither method works well unless the neck is perfectly concentric with the case body, which many commercial chambers are not, so fire forming in them creates a non-concentric case even if it started out perfect.

Custom match chambers OTOH often require specific case neck thickness and do best with bushing neck sizers as the bushings can be switched to get the exact size and tension required. What you are describing using a FL sizer to work only the neck is called partial full length sizing (it has other names). You still need to lube the case body with this method, which, as far as I am concerned negates the whole advantage of neck sizing with absolutely no measurable positive gain in either accuracy or case life. With a commercial chamber it makes no sense to me at all. You have a hunting rifle, not a match rifle. It was not built to tolerances tight enough to benefit from neck turning or reaming, beyond simply adjusting the brass to uniform thickness. And as I said, if the necks are noticeably asymmetric, there is a problem with the whole batch of cases and it is wiser simply to get a better batch.

Neck sizing, however, is the best way to get maximum case life with a rimmed or belted case (or any bottleneck case, but rimmed and belted cases are known for short case life due to overstretching of the case body in the firing cycle). Nothing is more versatile than a bushing sizer, but they cost twice or more what others do and for me a factory rifle does not justify the added expense. A conventional neck sizer with an expander ball works well, but still works the neck more than I think is necessary. For the money you can't beat a collet neck sizer for a factory rifle. Even if there is no real improvement in accuracy, the extended brass life makes it well worth it. Rimmed and belted cases have notoriously short case life, the higher the working pressure the fewer loadings you will get. Watch the case webs for the bright ring that signals an incipient head separation, and always check the cases before loading with a bent paperclip in the event it doesn't show on the outside. (You will feel a "ditch" in the case wall that the paperclip will catch on.)

As to brass, everyone has his favorite brand, some rifles are very particular too. I have had bad lots and good lots from every American and foreign brand over the years. Just like with primers, it is always a good idea to try several different brands when working up loads to see if the particular rifle has a marked preference for one over the other. IME you are less likely to see a marked preference in a factory rifle, but as I have yet to meet a rifle that can read "the rules", I test every rifle of mine that is capable of MOA or better. Sometime I get a big surprise. If after trying several powders and several brands and weights of good quality bullets the rifle won't do MOA with at least one combination, I don't bother with further component testing and I seldom hang onto them.

Despite what you read in the gun rags, most factory rifles are simply not capable of MOA, though average accuracy overall has been steadily improving over the years, and out-of-the-box, IMO you are more likely to see one that is capable in a Savage bolt action. I'm not talking about semi-custom and custom rifles that set you back several thousand dollars or more, just your average new hunting rifles under a thousand bucks.

In all honesty, it is not the tools that craft the most consistent and accurate ammo, but rather how they are used. Consistent force on the press lever each and every time, mastery of the powder measure with different types of powder, and careful inspection at each step in the loading process is the real secret to accurate ammo. Weighing each bullet and case, sorting them by weight, etc. Many loaders are not capable of operating a powder measure with extruded powder to within .1gr without using a trickler, but the tool is capable of it with a careful and consistent hand operating it. Bench rest records have been set with the simple $20 Lee Loader.

[konrad]

Well reasoned response!

As to your reference regarding non-concentric chambers and bores: I once read an article describing engraving a mark on the shell to be used as a locater in positioning the round in the chamber the same way each time. I believe this is a sort of back-handed way of working around this sort of misalignment.
Thanks for the post.

[fryboy]

the "cartridge indexing" ( that you once read a article about ) removes a variable from the equation , it's fairly easy to do in a single shot and a wee bit harder to do when fed from a magazine , it too however has it's limitations of usefulness ,consider for a moment that everytime you chamber and fire a shell it rest on the bottom of the chamber ,therefore it always expands up and outwards