CJW Posted January 31, 2012 Share Posted January 31, 2012 I decided a little while ago that I want to turn a spare lower into a 9mm SBR. I am going to have a trust drafted, transfer the lower into that, and then do the paperwork to turn it into an SBR. That part I have pretty well covered. What I am having a little trouble with is the 9mm upper. I have been reading as much as I can about it, and I have yet to find a simple set of build instructions. I've read about all the different mag blocks, ramped BCGs, 9mm buffers/springs, &c... But I'd like to see if I've actually figured out the basics. A 9mm upper is blowback, so there's no gas system. You can get upper receivers with no gas port. So, is it really the case that all I need for the upper are (1) receiver, (2) 9mm barrel, (3) handguard w/ barrel nut, and (4) 9mm bolt/carrier (ramped if I want a standard AR15 hammer)? Am I missing anything? Is it that easy? Buy it all, torque the barrel to 75lb.ft. and go? I've seen gas-clamp rails used on some builds. There's no gas ports to cover, so is that just to put the front sight on the barrel rather than the handguard? Lastly, it seems like a lot of the 9mm sources have dried up. Spike's doesn't have a lot of dedicated 9mm parts on their site anymore, but there seem to be a lot of variations of the Rock River Arms stuff floating around. Any other suggestions for parts sources if I want to build it myself? Thanks! Quote Link to comment Share on other sites More sharing options...
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