My M44, M39 bolts don't interchange

[p-t-max]

Well, not totally, anyway. I took the bolts out of my Russian M44 (1944r, Izhevsk Arsenal) and my Finnish M39 (1942 "B" barrel) and did some cleaning on them both. I didn't take them apart. Just out of curiosity I slipped the Russian M44 bolt into the Finnish rifle, but it would not close. However, the Finnish bolt (which is actually a Russian bolt, with markings from both Izhevsk and Tula arsenals) closed in the M44 with no problem. Well, to tell the truth, I expected both bolts to interchange, or neither, but only the one did. Is this normal? Was I wrong to expect both bolts to interchange?

[desdem12]

The one rifle may have a better headspace clearance. Or it could be a worse headspace issue if the one bolt is installed. The basicly interchange but some may have a bolt head that is too big to allow the bolt to close fully.

[Junk Yard Dog]

I would think it's the headspace, don't swap bolt parts around to find out, this can lead to parts getting mixed up.

[FINNADDICT]

Yup. If you have to change the bolt, you must do a headspace check. Same thing if you swap for a new barrel. It is a good idea to have a few spare boltheads of different sizes.

[p-t-max]

Thanks, folks. I used my Okie headspace gauge to check headspace, and both rifles passed the no go check with their "original" bolts in place. That is, the bolts would not close on the gauge; so I assume that both rifles are safe to fire with surplus ammunition. As advised, I will not swap these bolts, nor will I disassemble them together and risk mixing up the parts.

Thanks once again.

[Junk Yard Dog]