M91 Mosin Problem

[SKS Ray]

Yes I have a problem with no clear cut answer and I gotta ask here if anyone has info. My exact post on the Mosin forum:
I picked up an M91 from XXXXX XXXX a while back and finally took it out today after cleaning and re-assembling. Problem is I couldn't shoot it. I couldn't get a round to chamber.
The bolt closed 1/2 way and then wouldn't go further. I didn't want to force it so I left it and came back home.
XXXXXX says they check all their rifles for headspace so I didn't bother doing so when I checked out and cleaned the rifle. Now heres where it gets pretty interesting... after I got home I checked the chamber well with an inspection light, made sure there was no left over crud, burrs, etc. and figured I'd try a 7.62x54 snap cap. The bolt closed ok but with just a little pressure. Next with the rifle pointed in a safe direction (deep stack of firewood and concrete wall) I tried a Czech silver tip round and had the same results as the snap cap, a little pressure but nothing excessive.
The cuplrit I'm thinking is the Polish 7.62x54 ammo that I took with me to the range. I don't understand this though. It functions fine in all my other Mosins. Seems like a headspace issue to me. I don't have a 7.62x54 guage though and didn't figure it was worth getting one since XXXXXX says they check their rifles. Is it normal for some ammo to do this?
First time running into this problem in 4 years of milsurps.

 

[Wildweasel]

If you have a caliper check the different ammo to the specs and see which one is off. (one of them is!) I think I would get a headspace gauge or bring it to a smith to have it headspaced for piece of mind. who knows how the dist headspaced it.

 

[jhrosier]

Is it a Finn? They are known for tight chambers. Lacquered cases might be too big for some. A google search for "mosin" and "tight chamber" shows that it is a very common problem, usually related to a dirty chamber or crud in the bolt locking recesses or certain types of ammo. If your ammo only chambers half way, you might even have a separated case stuck in the chamber.
BTW, the snap caps are probably deliberately made small and are not a good indication of actual chamber size.

 

[SKS Ray]

I was thinking of a putting a 12 gauge bronze brush on a cordless drill and scrubbing up the inside of the chamber. That should take care of any crud or even a burr I can't see.
The replies I got on another forum mentioned some Mosins being finicky on some ammo. 12 Mosins later and I finally come accross one. No D stamp on the barrel I heard is also an indication of a tight chamber.