#1
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Oily chamber- Part II
Since there was some various opinion on the topic here recently I thought I'd do some additional research on the subject. What prompted my curiosity was the fact that the topic is also given some coverage as well in the new book just released by Mike Ratigan on extreme rifle accuracy. Mike is one of the best benchrest shooters around and his book is a treasure trove of information even if you do not shoot in competition. Anyway after reading the book I also asked 2 hall of fame shooters and 1 smith that has made more than 1 gun winning the supershoot. Other than case forming type stuff, all said that even in a BR chamber which has minimum specs, a case will regularly stretch from 1/2 to 1 thousanth upon firing which is why most shooters at a minimum will use a bump die for the shoulder. In anything other than a clean chamber, excess initial stretch will take place at the base-web leading often to premature case failure. As one hall-of famer stated with some humor, "that's why they sell all those chamber mops at Sinclair's"
Since this seems to be somewhat safety related I thought I'd share my results. |
#2
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Quote:
Oh, and I usually refrain from talking about this kind of stuff on the 'net too . - DAA |
#3
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Quick P.S...
Oh, while I'm on a roll and actually posting, worth mentioning one of the most common situations I have seen that calls for the lightly oiled case or chamber. And that would be fireforming brass for an AI chamber cut by a 'smith that doesn't understand how AI's work, and uses a GO gage for the parent cartridge - ending up with a chamber that's too long. I had two AI's built by a really big name 'smith that are like that. Head separations guaranteed, if you don't lighly oil the cases for fireforming.
- DAA |
#4
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DAA- I did just that, however merely re-cut the chamber without setting the barel back. I knew what would happen, just didn't care. Lighty oiled cases and with bullets seated to engage, ended up with perfectly formed brass. This was with the Swift - and 16% powder increase with 0 increase in velocity for the powders I had. It probably would have increased performance wiht the 'right' powder, but I cut her back and re-chambered to the shortened 1.5" Swift Imp. much the same as P&P did in the pre-Russian case times.
__________________
Daryl |
#5
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I've been using Ballistol when forming cases--really slippery and cleans up easy.
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