Our BM's have been in country since late 2004 and they have unknown rounds put through them. Thus far almost evry one that has been reamed has resulted in material being removed. We als ohave semi auto guns that are as of yet unfired and when I reamed two them a significant amount came out.
It's my belief that the tight chambers are a contributing cause of the popped primers, blown anvils and failures to extract that we have had with the Prvi Partizan and Bulgarian 5.56 SS109 ammo. In fact, in most of the guns that I reamed the problem was reduced though not 100% eliminated.
Quote:
Originally Posted by jmart
After viewing this thread, it got me off my ass and out to the workbench to make a cerrosafe cast of my BM's chamber.
I just took the measurements after waiting the required one-hour cool down time, and my throat/freebore diameter is right at .2265. Neck diameter is .2553 ( about 1:15 after making cast). It's very difficult to make a measurement of the freebore length because it's difficult eyeballing exactly where the rifling begins, but it looks very consistent with the example that Ned posted on his .223 vs 5.56 article in the Sep issue of SWAT (pg 68, chamber cast pics). This barrel was purchased in spring of 03. Round count is approx 3,000 but that's just a WAG.
Now I wonder if Grant reamed it whether or not any metal would come out, but hypothetically speaking, if it did remove some metal, what would be the conclusion?
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