Small pistol vs small rifle primer

A friend of mine sent me some 6ppc ammo someone has loaded fro his rail gun.
The loader has passed on to the great range in the sky.
Of about 40 loaded rounds 16 seem to have a primer that is sitting below the face of the case.
27 rounds fired fine the 16 that did not all seem to have a primer lower than the face of the case.
The cases are 220 Russian necked to 6mm and are Lapua brand.
I am thinking the loader ran out of small rifle and used small pistol instead.
What do you think?

I was thinking that also, but these cases (almost 50) were formed from 220 Laupa cases. I would think they would be pretty much the same.
I will pull heads and some primers tomorrow and do some measuring.

That is a possibility but these were only shot 2-3 times.
I have been reloading the 6ppc for over 25 years and never had a problem.
Only 16 out of 40 did not fire.

barnfrog said:

Only? 16 out of 40 is 40%.

Click to expand...

"Only" was not the right word to use. These rounds were loaded by someone I don't know. They are for a friend of mine's rail gun. He is not a reloader so I would load 6ppc for his rifle.

About ten years ago I moved to WV six years later to NC, but I would see him about three times a year (he is in PA). I would take his fired rounds home with me reload them then either take them back or ship them back to him.

About a year before covid hit he got this rail gun and had some local guy do the loading for him. He has never had a problem before, but I don't know what load this guy used. there is a label in the box that says: LT-32 28.2g Berger 64g.

I have not seen him in about two years because of Covid and the guy who was doing the loading for the rail gun has either moved or is dead.

The primers on the fired rounds have a very small cratering around the firing pin indentation, maybe a little hot?
That would not be cause for the low primers.

Well I think I found the problem, the primers that fired were .122" tall, the ones that did not were .114" tall. Well out of spec.
Both charge weight and bullet were right on the money, as well as the depth of primer pockets .125"- .126".