Reloading for the AR-15
- The most important step is to make sure the primers are slightly sub-flush, about 3 to 8 thousandths is correct.
- Primer type is not critical if it is seated to the proper depth. The "mil-spec" CCI primers are not necessary to prevent slamfires in this rifle. Avoid Winchester Small Rifle primers because the current batches have such thin and/or weak cups that they are prone to piercing at moderate charge weights.
- The neck tension you are getting with the die and case combination you are using is insufficient. Try sizing some cases with the expander ball removed from the die - this will eliminate stretching the case neck and expanding the neck too much, and it might fix your problem. You can turn the expander ball down a few thousandths by chucking it in a drill and applying abrasive. If you size with the expander ball, be sure to lubricate the inside of the case neck.
Buying new cases [buy Winchester, not Federal, not Remington, not anything else**] might help the neck tension problem, but it won't be the final solution. **Norma or Lapua will work, but they are very expensive and certainly not necessary at your stage of learning.
You can buy bushing type sizing dies for better control of neck tension and sizing, but you should probably try the steps above first.
To test for sufficient neck tension, seat a bullet (in an unprimed and uncharged) to the normal depth. Hold the dummy cartridge by the case and push it into the edge of your bench - you should be able to lean on the cartridge without seating the bullet deeper. This is good neck tension. You will develop a feel for correct neck tension while you are seating the bullet with a little practice.
- Crimping. Do it if you must, but it is not necessary as proven by thousands and thousands of reloaded rounds shot in AR's every week in this country. Don't bother to spend your money on match grade bullets if you crimp.
- Single Loading AR type rifles
Push the cartridge completely into the chamber, then release the bolt. If the primer seating depth is correct, it should not slamfire. If you allow the bolt to carry a cartridge into the chamber from rest on top of a magazine follower (type doesn't matter), it might slamfire.
- Don't waste your money on titanium firing pins in hopes of curing this problem.
- Every hollow point, .224 diameter match bullet manufactured will feed from the magazine in an AR. The hollow point opening is a tiny fraction of the bullet diameter - the barrel extension is screwed up if it won't feed these bullets. Even the 75 to 80 grain bullets intended for single loading will feed from the magazine if seated deep enough.
This story about misfeeding "hollow points" is just plain malarkey.
- Here is one other detail to be alert to. Accidental dishcarges mistaken for slamfires are possible if you have a trigger with a very light trigger pull and an extended bolt release lever installed. It is very easy to touch the trigger and fire the rifle when the bolt release is tripped with the trigger finger - been there and done that!