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bolt dimensions?


ball turret

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i'm having a minor headspace issue. it's nickel-boron and i'm thinking the high spots from the plating process are the cause. i have a lot of experience with chrome doing that and have made countless repairs on non firearm details. anyway, if anybody has a print for the bolt or at least the bolt heat thickness and tolerance, i'd appreciate it.

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The go. it will go on a cartridge, but not quite on the gage. it's probably only off by .0005 or so. just thinking the rear of the bolt head and the cartridge surface have some plating build up. the bolt functions fine in the carrier and most likely was good before the plating process. i see this all the time in the trade i'm in. i do precision maching and grinding in the gage industry. many customers want chrome or nickel plating for corosion protection and it's alwas a crap shoot judging how much undersize to make a part so that it will be within tolerance after plating. i can correct that, no problem. i can take off .0001 at a time, i would just like the bolt to be in spec when i'm done, can't find the spec though.

Edited by ball turret
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Your cartridge case will fit in the bolt head cartridge pocket , but the head space gage ,will not ? Is that correct ?

 

If so , what manufacturer made the gage ? Did you try fitment & head space , with the ejector & extractor removed ? Some gage's require you to do so & some just ejector removal is required & yet some need no disassembly at all of the bolt .

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Your cartridge case will fit in the bolt head cartridge pocket , but the head space gage ,will not ? Is that correct ?

 

If so , what manufacturer made the gage ? Did you try fitment & head space , with the ejector & extractor removed ? Some gage's require you to do so & some just ejector removal is required & yet some need no disassembly at all of the bolt .

the gage fits fine in the bolt head. the bolt won’t close on it in the barrel extension. to me, this is one of three things and i'll go out on a limb and say that the barrel manufacturer (match barrel) fitted the extension properly.

 

1. the chamber isn't deep enough. (not likely)

2. the bolt head is too thick. (possible from coating irregularities)

3. the cartridge pocket is too shallow. (possible from coating irregularities)

 

the gage set i have is from a well known manufacturer. since there are three guns being built here i verified chamber dimensions and inspected the gage set. it is correct to the high end of standard gage practice tolerances. the first rifle was built with a premium, but unplated bolt. it was a flawless fit. the second and third builds are using the same barrel but a different BCG. this completely disassembled bolt is tight on the go gage. i can chamber a round with little effort, and I’m sure that during normal function the rifle wouldn’t notice it. However a hollow brass tube is more forgiving to pressure than a solid steel gage. The bolt will just try to start on the gage, but it’s too tight to go all the way and I won’t force it and risk damage to the chamber.

So  TTT. I need the bolt specs (sizes with tolerance) so that I can make the correct repair without taking the bolt out of tolerance. In the process I would be making the bolt have better geometry. That could help accuracy (these are to be 600 yd rifles) that would be a good thing. On the other hand, like tripleduce said, it will wear in soon enough. I’d still, analy speaking, like to fix it.
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I also believe its fine  & probably tight because of the coating . I would be happy to have a snug "GO " gage on a match barrel . 

 

Take her out & do your safety checks of the action & safety  & give the rifle some break in rounds, if all safety checks work out ok & spent cases look OK . Then check head space again, I think you will be satisfied with the outcome.

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