I load a lot of .223 Rem for both a Colt HBAR that I use on the National Match course and an old Sako Vixen.
As M&P45acp notes, watch your case length and keep your brass for the rifles segregated.
When using Lake City brass or any other military brass (WCC, FC, TZZ, etc.), be sure to swage or ream the pimer pocket crimp from the head of the case. Military brass lasts for ever and other than reaming the primer pocket and trimming to length the only other thing that I do is establish an average weight for the batch of brass I'm prepping and throw out the heaviest and lightest of the cases. This step seems to reduce the number of uncalled flyers (that darned 8 ring hit at 10:00 that you call dead center) at 600 yards. Some shooters also segregate their LC brass by year of manufacture, but I think the weight is more important.
The M-16/M-4/AR-15 platform is surpisingly easy on brass. If you buy surplus brass, it may have been fired in the M-249 SAW. That weapon can be pretty hard on brass and I stay away from it. As I'm in the military, I'm often issued ammo for matches so I'm able to pick and choose where my Lake City comes from.
I use Winchester brass in the Sako and usually just neck size it until it gets stiky to chamber. I use a special Redding sizer with interchangable internal diameter collets for this.
In the HBAR I generally use 69 grain Sierras at 200 and 300 yards and 77 grain or 80 grain Match Kings at the 600 yard stage. I've been thinking about using the 75 grain Hornady match bullets this year accross the course as that will simplify the loading preparation. Several of my comrades use just the 77 grain Nozler or 77 grain Sierra MK accross the course with good success.
In the Sako, 52 or 53 grain Match Kings work wonders on the vermin that I target with it and hold well out to 300 yards or so, unless the wind is kicking up. Any good quality bullet works well though, but the Blitz type are best for prairie dogs.
For powders I generally use Olin 748 or H 335, but other powders work well as the .223 is pretty ammenable to any powder with a moderate burning rate.
The same applies to primers. I've had good consistancy and accuracy with CCI, Remington and Federals. I just bought a brick of Brazilian Magtech primers, but I haven't got around to testing them yet. If they work well, I'll try them during the match season this summer. I've never bothered using the magnum primers in the 223, even with ball powder. It's a pretty small case and the standard primers seem provide enough spark to get things going. No all of my friends agree though, so test that for yourself.
In your bolt rifle, if the magazine is long enough, you might try loading the bullet out to just shy of the rifling. This will often improve accuracy. In the AR platforms, the magazine dictates the overall length of the bullet, but for the 600 yard slow fire stage of the NM course, I single load them and so seat the 80 grain projos out to touch the rifling.
One nice thing about the 223 is that it is easy on barrels and they last a long time. After almost 40 years, my Sako is due a third barrel and the HBAR seems to be ready for a new one after 20 years of off and on again shooting.
I hope this helps. I also shoot a lot with my son and there is no better sport than shooting and reloading to cement that good relationship.
US Army Distinguished Rifleman
Washington State Distinguished Rifleman
NRA Police Distinguished Expert
Last edited by Scharfschuetzer; January 31, 2012 at 11:44 AM.