My M1A is not a match rifle. Its not "loaded", its not SOCOM, or anything but a "rack grade" gun with all GI parts on a Springfield Armory receiver.
So, I take a slightly different approach to its ammo than the gun shooting matches.
For my reloads, I just duplicate GI ball ammo. 150gr FMJs at spec speed (2750fps +/-).
I generally run GI brass, with the primer crimp cut out, last few batches I used W748, bullets seated to the cannelure and crimped.
My .308 dies are Lyman and actually the very first die set I ever got, bought in the early 1970s
Sizer die is FL and set for solid contact with the lyman shell holder with all play out of the press linkage. Seater die is adjusted correctly (does not contact the shell holder) to seat and crimp in one step. Very uniform, IF your brass is. Which is something that I do, brass is checked and trimmed to a uniform length and die adjusted for that brass.
I use CCI 200 primers, because I have them, and they have always worked safely, IN MY GUN.
The M14 (M1A) has a floating firing pin. When the bolt stops moving forward the pin still is, and as the bolt cams shut the pin bounces off the primer, often leaving a little dent in commercial primers with regular thickness primer cups. The slightly harder primers that meet the GI specs may or may not be visibly dented. I do not argue with the people who say the GI spec primer is the one you should use. I don't, but that's my choice, and I won't say you should , your rifle is not my rifle.
I graduated second in my class (and made PFC because of that) of Small Arms Repairman (MOS 45B20) from the US Army Ordnance Center and School at Aberdeen Proving Grounds in 1975 and my class was the last class trained on the M14 rifle.
I couldn't build you a match rifle, won't even try. But I know the basic service rifle, rack grade, inside and out. I've owned or had experience with some variant of all the world's primary service rifles from 1890s on up through the 1980s, the actual rifles or semi auto legal copies of the select fire ones. All the semi autos have gone on to new homes, my M1A is the one I kept. It fits me and I do ok with it. It shoots better than I do, I suspect.
Was shooting some reloads in my M1A Loaded, when I got a misfire.
I attempted to pull the bolt back and found the bolt was jammed and would not pull back. After several attempts it finally released and I was able to eject the unspent round. There was a slight dent in the primer.
Are you aware of the "soldier's drill" for when that happens?? I don't think its taught any more,, but I got taught by some experienced Sgts when I was in.
(and, bear in mind this is for when no one is shooting directly at you
)
First off, STOP, and look at the rifle to see if the bolt is fully shut and locked. IF not, smack the hell out of the back of the op rod handle to see if you can force it closed. Kicking it is also an option but that's quite awkward.
There is a restrike capability in the M14. Its awkward, but possible. Unlatch the trigger guard, and pivot it all the way forward, like using the lever of a lever action rifle. This will recock the hammer without needing to open the action. close and latch the guard, and refire the rifle. IF the bolt is fully shut, it should fire. IF it does not, then try to eject the unfired round.
IF you can't get the action open, then it's time for the other part of the drill. Place the butt on the ground, hand on the barrel just below the flash suppressor, leaning the muzzle away from your body slightly and, maintaining control of the muzzle, stomp down on the op rod handle. This will normally pop the action open, ejecting the unfired round.
Chamber another round and get back in the war!
This "drill" is rough on the gun, it is a field expedient for use in situations where what's best for the rifle is of no concern. I wouldn't think of using it under any but the gravest of circumstances. (meaning actual combat)
If you're feeding a match grade rifle match grade ammo, do what the match shooters tell you to do. If you're not, and regular "rack grade" results are good enough (as they are for me) do what then do what you need to do with the ammo so your rifle runs right, and save the "fiddley stuff" for rifles that can use it.