To start off, I just got a mosin nagant 91/38. It is in great shape, shiny bore, and plain old nice everything. This rifle is tula arsenal receivered, but with some other mixed parts (compliments to CAI importation or refurbishment). As I am poor, and buying twenty dollar parts multiple times is not a reality, I will give you guys some observations and measurements and ask for your opinions. Im trying to make the best decisions about what to buy and what is needed or not. I first gauged the headspace with scotch tape. I know the 7.62x54r headspace measurements, .71 no go and .74 field. Measuring the rim of my bulgarian surplus, via my bolthead, comes out to .066". Then measuring the pieces of tape to get the bolt to bind, comes out to .012. So those together come out to .078 headspace. .074 is field gauge specs (like I said). So I decided this was close enough to test fire my rifle strapped to a rest, with a paracord trigger string. First shot, fine, no resistance on the bolt to extract the shell. Second shot, fine, only a little resistance to pull the spent shell out. Measurements. Please, if someone could measure their spent steel cases to compare, that would be awesome. case neck shoulder 1/2past shoulder base unfired .332 .453 .466 .484 1st fired .337 .461 .473 .489 2nd fired .336 .461 .472 .490 So in the neck I am seeing a only a .004 difference. At the shoulder im seeing a .008 difference. Half way between shoulder and base im getting a .007 difference. And finally the base is a .006 difference. Along with these measurements, some observations. The case shoulder looks a tiny bit higher than a nonfired cartridge.. There is a small ring around the bottom of the fired case, which is where I measured. It however, looks nowhere close to rupturing. Lastly, neither of the cases will rechamber in the rifle. It seems they are expanded too far. My question is, does this seem off? Does this seem dangerous. I am torn. Im quite sure there are many guys out there shooting their mosins with the same results, just not noticing, with no problems. But I notice all the details, I just dont know what to think of them. I would buy a headspace gauge, but already know its a bit off (and can find out again). I would buy different bolt head, if I thought this might be dangerous in any way. I assume many folk have shot their mosins without incident in the same condition. I just need some help.