I have a Coharie arms CA 94 carbine that I SBR'ed. When it was a bastard 16" grotesque mockery of an MP5, it had several stovepipes in the first 200 rounds. I got the form 1 back from the ATF and chopped the barrel and welded on a three prong flash hider. Since then, I have had NO problems!!! How can reducing the barrel length solve these problems? Or do you think that 200 rounds was the magic number? Since then I've put another 600 rounds through with NO problems what so ever.....weird