Home Forums Hunting & Shooting Gunsmithing off-center firing pin strikes

I've noticed that some rifles hit primers off-center to varying degrees. Is this indicative of a problem with the alignment of receiver and chamber, or of the bolt itself? Is this anything that needs to be (or can be??) corrected?

What kind of rifle?

The majority of off center hits is a result of slop between the chamber and the brass. Because of gravity, the case tends to lie on the bottom of the chamber which pulls it out of alignment with the bore and firing pin. People neck size in an effort to reduce this slop which, you can imagine, has an adverse affect on accuracy. The majority of people are content with the off center hits provided the gun goes bang. And then there are guns with off center chambers and firing pin holes.

It's happening on both a Model 70 (new BACO) and a Rem 700 CDL-SF. Both are reasonably accurate, but somewhat variable depending on load. I just wondered if there was anything that needed to be corrected. The loose chamber makes sense. If that's all, who cares... It's better to have a little room there, I assume, to tolerate dirt. Thanks for the info.

Dunno about that gravity theory. I would buy short brass for a sloppy chamber and the bolt being cammed up by sear pressure, but if your cases are just laying in the chamber I think you may be shooting the wrong ammo. Yes there are off center chambers and firing pin holes.

I have seen firing pin hits a little off center and the rifle still shoots under a 1/2 inch and i have seen dead center hits that won't group under 1.5 inches with every load tried. I just don't believe a small amount of off center hits makes a lot of difference in a varmint or hunting rifle. Bench Rest rifle shooting it might make a difference when a thousands of a inch may be the difference in winning or loosing. I agree with Malm a small amount of slop in the chamber will cause this plus a oversize firing pin hole can cause this. You see this with plunger type ejector because of the pressure exerted on one side of the case and pushing the case to one side

I agree the plunger can cant loose cases in a sloppy chamber, but not gravity.

Indeed, bolt nose ejectors can aggravate the problem, but there are off center hit and lop sided fire formed cases coming out of guns without bolt nose ejectors. And if you want to know for sure, mark the top of a case, invert the gun in question and see where the primer strike is in relationship to the ones held in a normal position. Kinda like the "Gangsta" hold, but with a rifle.

Is the firing pin hole centered in the bolt face? I've seen several that were not. It is a relatively simple matter to bush and re drill the hole if it is. If the chamber is oversize, but round, fire forming and neck sizing would be a cure.