Measurement varies?

[joatmon]

While measuring from front of receiver ring to the bolt face and extractor on a 93 mauser, measuring twice(more like 10 times) to finish ream once the numbers changed a lot too the tune of almost 10 thousandths. I took the action out of my unairconditioned shop to my unairconditioned den. The measurements were taken over about 45min along with other measurements. Because of 50year old eyes and infrequent depth mic. use my readings were sloooow! I was also up close to an incandesent bulb desk light so I could read the mic. With the heat from my hands and the light could the 1 inch rod in the mike have expanded that much? I'm not reaming yet nor will I till I get several repeatable readings.
Thanks Aaron

[chevyiron420]

Aaron, make sure the bolt is completly stripped and the locking lug receses are real clean. make sure the action face is without burrs. depth mikes are hard to use. its very difficult to feel when the little shaft is making contact with the bolt face without jacking up the body of the tool. also stay away from the fireing pin hole, sometimes there are burrs there.-phil

[Phil]

I have NEVER seen one of those old actions that were true! And most new ones are about as bad. Going from one side to the other of the inner collar on a M09 Argie I had over .006" difference. The bolt was about as bad. One Ruger No.1 that was brought in for rebarreling was so bad that you could see daylight part way around the barrel/ receiver face. Everything has to be trued, without seeing the parts I'd say you probably are seeing .010" difference side to side. Chuck the bolt up in your lathe and put an indicator on it, I'll bet you aren't making any mistakes, I'll bet the thing really is off that much.

Cheers,

Phil

[joatmon]

Thanks,going slow here and may true up reciever face before going further. I'm trying my hand at a 7.62X39 convertion.