Primer depth

[alphabrace]

Hello,
I am reloading for a striker type semi auto, an M&P, and I was wondering if there is a rule of thumb for primer depth not to exceed for this type of pistol. Thanks.

 

[Scrapper]

.003"-.005 is what I read in one of my books, I think the Lyman 49th. I think the main thing with primers is that it's important to get the anvil touching the bottom of the primer pocket with the primer just below the case head by a few thousandths.

 

[H Richard]

You will find there is very little variation in the primer pockets in brass. Certain brands will be a couple thousandths deeper than others. It is seldom any problem. Uniformity is more important to accuracy. As scrapper said, seat all primers so they are fully seated, the anvil inside snug against pocket seat. You want no movement of the primer possible when you strike it.

 

[blatzpac]

primer seating depth

i have found that using a hand held priming tool gives good sense of feel for the primer bottoming out in the case. a quick way to verify if primer is fully seated is to run your finger or thumb nail across the case bottom; if the primer feels like it is above the case, a "high primer" condition exists. just put the case back in the tool to seat a little deeper. i have experienced a very tight fit on some new cases when installing primers. a little dry moly lube on a q-tip will make them seat much more easily. good luck! reloading is great fun.

 

[Arisin Wind]

Seat them until they are fully seat in the primer pocket.

 

[Pisgah]

I will second the idea of using a hand priming tool. A dozen rounds is enough to give you the "feel" of things as the primer bottoms out. In thousands of rounds loaded, I have never had a single problem that could be blamed on improper primer seating. The "ideal" scenario is primer seated just below the cartridge base with the anvil in full contact with the case and the primer material within just slightly stressed in direct contact with the anvil. I would think that this being too deep for reliable functioning would be a sure sign of a too-short striker or firing pin.

 

[OKFC05]

Seat them until they are fully seat in the primer pocket.

This.
An inertia striker will keep going until it hits the primer. If the primer is not seated, it will cushion the blow and can cause misfires.

 

[n4zov]

I will second the idea of using a hand priming tool. A dozen rounds is enough to give you the "feel" of things as the primer bottoms out. In thousands of rounds loaded, I have never had a single problem that could be blamed on improper primer seating. The "ideal" scenario is primer seated just below the cartridge base with the anvil in full contact with the case and the primer material within just slightly stressed in direct contact with the anvil. I would think that this being too deep for reliable functioning would be a sure sign of a too-short striker or firing pin.

Exactly right! I don't know of anything that equals a hand held priming tool.