Re: RCBS Precision Mic
Whenever we size a case, there's several different dimensions in the mix that we're changing. Full-length sizing does the most thorough job of returning the case to nearly it's original, unfired dimensions. Since the case stretches longtitudinally as well as circumfrentially, there's generally some degree of interference between the shoulder of the case and the shoulder of the chamber. Neck sizing (as the name implies) alters only the neck dimension. You may not have had any problems with hunting ammo from just neck sizing, but eventually, you will. Mr. Murphy will virtually guarantee it, and I'll add that it'll come at the most inopportune time. Sorry, just works that way. If you choose to neck size your hunting ammo (and I'd strongly recommend against it) you will still need to full length resize occasionally. Otherwise, that interference will continue to worsen, and you'll find youself pushing a bit to get the bolt to cam over and close. Full length sizing is just insurance in the field, to make sure this never becomes an issue for you. Otherwise, at some point, you won't be able to get the bolt closed. Long way to say it, but yes, you need to bump those shoulders.
The secret to best accuracy and long case life, is simply not working the brass any more than you need to assure easy and reliable chambering. But that doesn't mean doing so to the extent that you risk chambering problems, at least in my opinion. Elsewhere, we have a thread going concerning chamber gages, like the RCBS Precision Mic. A gage such as this (or any of several others out there) will allow you to bump those shoulders back by a set amount (one that you KNOW, and can measure) and you'll know you're not working the brass to any excessive degree. The best of both worlds, and I can't recommend these highly enough. Well worth the $, and the time it takes to use them. Hope that helps!
Last edited by Kevin Thomas; 03-03-2010 at 09:21 AM.