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Old 08-28-2012, 08:45 AM
Bob S Bob S is offline
Join Date: Oct 2009
Location: Northern Virginia
Posts: 1,094

Originally Posted by MajWatz View Post
Would that mean test rigs/receivers had the capability of being adjusted for short chambered barrels when proof fired?
You guys have assumed that the barrels were proved with the "standard" cal .30 pressure test cartridge which was used to prove the assembled rifle. They were not. Early in '03 production, the chamber was not even fully cut, nor was the breech coned. Colvin & Viall has a a drawing of the "proof chamber". The idea was to weed out barrels of defective material before a lot of time and money was invested in further machining. The cartridge was rather funny looking.

The WW II era process instruction that is in the back of Brophy's book indicates that barrels were proved with the "finished" breech (coned) and chamber (i.e. the short chamber) but before finishing. There was also use of MP testing (magnetic particle, Magneflux) by that time. I have not seen the barrel proof cartridge of this era, but it would have to be short; you couldn't have .050" of the base of the standard pressure test cartridge hanging out in space. Not recommended procedure.

I wonder if Ray Maketa would have examples of these cartridges ... ?

Bob S.
USN Distinguished Marksman No. O-067

"It's REAL ... it's wood and steel!"
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