M1 primers

[richard pries]

I reloaded a bunch of brass with 47 gr 4895 and 150 gr bullet . Some of my primers wound up with holes in them , i was told you should use hard primers for m1 ammo . Can anyone varify this ?

[tmark]

Yes, I have heard this too. The M1 has a floating firing pin. If you slam the bolt on a round, and then extract the round from the chamber, you will see a slight indentation in the primer where the firing pin hit it.

If the primer is too soft, a slam fire could result. Not good.

I have always used Winchester large rifle primers with no problems.

[High Plaines Doug r]

Look closely at your firing pin nose. If it is eroded and causes an un-uniform primer indent, that can lead to primer piercing. (leading to more erosion, etc.) Otherwise, Winchester, Remington and CCI primers are adequate for M1 loads.

[joem]

I mostly use CCI and have never had any problems or a slam fire.

[13Echo]

Where are the holes? If in the firing pin indent then you may have, as noted above, excessive protuberance of the fp nose or a badly shaped nose. There have been recent batches of Winchester primers that will develop holes in the edge of the primer cup as a defect in the primer and not a fault of the firing pin or from excessive pressure.

Jerry Liles

[Twinson]

I have just used standard WLR primmers for years. Never have a problem. But your mileage may very.

[PhillipM]

I have some of the faulty winchester primers. It's not a rumor.

[Sunray]

What brand are you using? Any standard large rifle primer will do.
Slam fires are caused by improperly loaded ammo, not the rifle.
CCI's so-called "milspec" primers are just magnum primers.

[richard pries]

winchester and cci

[Hefights]

Do both Win and CCI primers pierce, or just one type? That would be important to note. Can you post some pics?

I believe all LR primers have same cup thickness and probably material & similar hardness. I think that CCI 34 primer sensitivity is adjusted by gap from the anvil. So not sure those will help.