Re: Advise on Reloading for AR15 NM Service Rifle Comp
There are two ways to approach this. One is with a smaller number of cases that well exceeds the amount of rounds you'd shoot while not having access to your reloading bench, and the second is to load for the season and not worry about ammo all year. I've done both, usually both at the same time. I've had a batch of practice/reduced local match cases that I'll load over and over, but at the same time my "real" match ammo is in bulk where I keep good track of how many firings are on the brass.
This is where knowing your headspace dimension, having all rifles with the same chamber, and all with the same headspace dimension really comes into play. The life of your brass is directly related to how much you size the brass relative to the chamber. If you had both a Holliger chambered upper and a factory RRA, then sized all brass to fit the Holliger, you are going to greatly shorten your brass life.
Assuming you stick with the same headspace dimension/chamber reamer in all your uppers (not hard to do since John also sells some nice games type of barrels for your SPR/DMR build you'll inevitably do once you get used to shooting an accurate AR) and moderate loads, you should get at least 6 firings from your "match" brass before it gets put in the "blaster bin".
Keeping the case/loaded round count up will also discourage you from trying to tweak your ammo from one loading to the other.
Before you load ANY ammo, wait until your upper is here. We need to 100% make sure your sizer is set up to the correct headspace adjustment for your upper. Given the tolerances of consumer grade reloading gear, you may have to modify your sizer or shell holder in order to get the headspace back where it needs to be. Honestly you can pretty well plan on needing to take your die over to Lee Wells and have him take a few thousandths off the bottom of it in his lathe. This will be mandatory if you plan on shooting once fired LC brass as the chambers in the NATO M4 and M249 rifles that fire it can be pretty generous, requiring more sizing (due to springback) than say a new WIN commercial case fired for the first time in your Holliger upper.
The reason for all of this diligence is pretty simple. If you do not keep track of your firings or load in such a fashion that you are oversizing the brass, in 223 you will get head or mid-case partial separations when the brass gets thin. When this happens, the case usually will stay intact and eject, however the loss in pressure will result in a 7 out the bottom. A full separation can come up even lower.
The AR takes these separations in stride from a safety standpoint, but they are most certainly detrimental to your score and do nothing to help your confidence for the rest of the match or practice.
The aforementioned points regarding firing count, resizing diligence, and case separations also mean that you must be careful to not mix range brass or other people's match brass in with your match brass. If there is any doubt about a case's origin, throw it in the blaster bin. Load from your blaster bin for a winter match or practice in snow or mud where you don't have much chance of recovering your brass.
