Hey folks- I'd like to assemble an AR upper and dedicate it to shooting cast boolits. Specifically, I'd like to install a 20 to 24" barrel with a 1 in 12" twist and have a larger gas port installed (maybe like the ones used in AR pistols) to ensure functioning with lower velocity lead boolit rounds. I've assembled and substituted a lot of components in AR lowers and my gunsmithing skills are pretty good (but not on a professional level). However, I've never attempted to assemble an upper. Specifically, I was wondering if anyone has any experience or resources they could share in the following areas:
1. Where I can find good instructions for building/assembling uppers with custom barrels
2. Good source(s) for custom built AR barrels (1 in 12" twist with larger gas port for cycling lower pressure rounds)
3. Good source(s) for the other parts needed to assemble an upper
4. Any other advice for best possible accuracy (like free-floating the barrel, etc.) would be most welcome!
Many thanks,
Bill