Semi Auto Rifle Reloading

[x101airborne]

About to make a run for my M1A and my LR-AR-308's. 
On primers, I am out of "Mil-spec" primers and remember about slam firing on soft primers. 
I know Federal is out (I do remember at least that much); any suggestions or warnings?
Ten years ago I loaded 3 thousand "M118 Special Match" and am just now out. But it has been 10 years since I loaded any so I need a refresher. 

Thanks all. 

[boolitdesigner]

There is a whole lot of misinformation out there on this. Test your primer of choice yourself. Seat a primer in a case with the primer below the case head (easily felt with your fingertip), chamber it and let the bolt drop.... about ten times and examining the primer each time. The firing pin indent doesn't increase in size nor does it go off. Primers slam fire from a high, non seated primer....period.

[bigbrowndog]

In 20 years of multigun and 3 gun, we never worried about “slam fires” with AR or M1a based guns, nor do I recall ever hearing of one in a properly functioning rifle. Bouncing a finger on the trigger YES, Running “experimental” trigger parts YES, but a properly configured gun using proper aftermarket parts or milspec parts, NO.

I’ve run, Winchester, CCI, Wolf, Tula, and Fiocchi primers with both AR and M1a based 308 platforms with no doubling.

Trapr

[x101airborne]

I messed up once and put my bolt gun loads in my AR 223 (Federal Match Primers).
Slam fires are real. I absolutely know that for a fact. Never again.
Admittedly, the primers were flush, not recessed. 

[boolitdesigner]

I would suggest you measure the primer depth below the case head on some military 5.56 and 7.62 loads and duplicate that on your loads. There is a spec. on this. There are several reasons factories do the things they do..... and they know much more than the large majority of handloaders do. Several progressive loaders have that as an adjustment on their machines.

[x101airborne]

Been ruminating on this the last couple hours since posting.
I went to using a Lee hand priming tool cause I can use it while watching TV.
Primers were barely flush to proud. Certainly not recessed as they should be.
I changed out a couple parts and got proper seated primers. All is good on the home front!

[jd]

I've loaded thousands of rounds for my M!A and several Garands with CCI and Remington large rifle primers and never had a problem. Back when I started shooting high power, mil-spec primers were not available and everyone used CCI, Remington, or Winchester primers. If the primer was seated flush or below, and the rifle was in spec, there was never a problem.....

[nolongcolt]

As important as primer seating is only feeding ammo from the magazine. Its designed to slow down the chambering and lessen the chances for a slam fire. I have used all manner of primers in many M1A/M14 rifles and several AR's of varying brands with no problems. Never put a round in the chamber and let the bolt fly home on it, its just asking for trouble.

[pbcaster45]

I always use a Carbide Primer Pocket Cutter on my M1A brass. I mainly use Winchester Large Rifle but CCI and Remington are good too. The late Glen D. Zediker wrote a really good article on reloading for the M14/M1A. It's too big to attach but here is a link to download it.

pdf4pro.com/amp/view/section-9-reloading-for-the-match-m14-2a5c6e.html

[450ak]

Yes your primers need to be below flush. The shoulder of the fired case must be pushed back to two or three thousands short of the chamber dimension. The case will stretch as the rifle is fired. Trying to neck size or other idiotic techniques will cause dangerous problems with your ammunition. M1 A brass us good for three firings and then maybe one in a bolt rifle. The web has stretched quite a bit and if you insist on continuing its use you will get head separations or worse. It’s relatively easy to get an M1 Garand to fire out of battery, usually breaks the receiver and stock. Can also damage the shooters hand.
The M1A is a little better about not firing unless it’s locked up.
AR series rifles are the best so far and they don’t stretch cases unless your using Federal. Military brass is the best for semi autos since it’s been tested thoroughly in semi and full auto fire.
This my experience in shooting the throat out of three barrels in High Power service rifle competition. An expensive Obermeyer barrel lasts 3500 to 4000 rounds, it’s the rapid fire stages that heat it up. That’s why AR15 barrels will run much longer since it’s half the powder charge.

[450ak]

Also my friend and gunsmith of match grade M1As will teach you the same. And he is a High Master with an M1 A service rifle

[boolitdesigner]

Apr 10, 2021 10:48:09 GMT -5 450ak said:

Yes your primers need to be below flush. The shoulder of the fired case must be pushed back to two or three thousands short of the chamber dimension. This is why you get such short case life. The case will stretch as the rifle is fired. Radially, but you can re-chamber most all cases fired in the rifle. Trying to neck size or other idiotic techniques will cause dangerous problems with your ammunition. M1 A brass us good for three firings and then maybe one in a bolt rifle. Maybe...I use military cases myself and get long life from them..... with one caveat, I fire cast bullets at near full power for the bullet weight. The web has stretched quite a bit and if you insist on continuing its use you will get head separations or worse. If you insist on setting the shoulder back each time that is exactly what happens. It's called reloader error. It’s relatively easy to get an M1 Garand to fire out of battery, usually breaks the receiver and stock. Can also damage the shooters hand.
The M1A is a little better about not firing unless it’s locked up.
AR series rifles are the best so far and they don’t stretch cases unless your using Federal. Military brass is the best for semi autos since it’s been tested thoroughly in semi and full auto fire.
This my experience in shooting the throat out of three barrels in High Power service rifle competition. An expensive Obermeyer barrel lasts 3500 to 4000 rounds, it’s the rapid fire stages that heat it up. That’s why AR15 barrels will run much longer since it’s half the powder charge.

Besides the above, I have shot most of the military type semi-autos using my own parameters with long case like and excellent accuracy. My little groop have several M1A's with 10,000 rounds down the barrel with little bore wear and slightly elongated gas ports....... all with loads as stated above. Not everything is what it appears when you reload.