Steve Poll said:
That was close, Dave. No wonder it was so hard to chamber on that end!
When breech loading firearms are loaded from the muzzle end, one is often left with excessive headspace.
Speaking of checking wear on bores, I slugged some bores tonight. Some of you may find this interesting.
Yugo SKS, date unknown, obviously used: lands .301", grooves .313".
Chicom SKS, date unknown, nearly new: lands .301", grooves .312".
Romanian AK clone, late nineties, rode hard and put away wet: .302", .312".
Russian M38, 1943, rearsenaled in 1994, used lightly since then: .305", .315".
Russian M38, 1943 rearsenal: .305", .315" with a loose spot.
Romanian M44, 1954, apparently unissued: .303", .315", large loose spot, bore is not round.
Russian SVT-40, 1940, beat to hell and back:
Oh, God. .380" fishing weight used as a slug deformed too little for a meaningful reading. Rifle is deadlined and will be sold at the next conveniant WAC show; potential owners will be warned that the rifle is OOC and no longer safe to shoot.
Looking at the numbers, one would guess that the second M38, the M44, and the SVT wouldn't shoot accurately. They don't. (The SVT is particularly inaccurate. Now I know why.)
For comparison, I mic'd three randomly selected 7.62x54mm cartridges from three manufacturers and 1 cartridge of 7.62x39mm.
Wolf 200 grain soft point, late nineties vintage: .3105".
Czech silver tip, date unknown: .310" on the dot.
Albanian surplus, late eighties date of manufacture: .310"
Wolf 123 grain ball, 7.62x39mm: .311"
None of the x54 bullets are really correct for my bores. The Wolf tends to shoot more accurately than the others...now I know why. It will be interesting to see what these rifles can do with appropriately sized bullets and a bit of care in assembly.
The x39 is a bit small as well, although one can usually get away with a .001" difference; even jacketed bullets will bump up a little. None of my rifles in x39 can be considered really accurate but the Yugo is acceptable. Again, I'm looking forward to seeing what difference (if any) larger bullets will make.
Where am I going with this? Slug your bores. (This goes for new production weapons as well.) You might be surprised at what you find.