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Posted: 2/7/2026 5:02:12 PM EDT
| I've had this idea running around in the back of my head to build a 5.7 AR pistol w/ a folding brace. Been thinking about one of the uppers that users P90 mags but they seem clunky. Was looking around a day or two ago and ran across a couple of lowers that have the built in folding bracket on them. Am thinking about something like that and build an 8" (probably) AR w/ the CMMG barrel and bolt. Anyone know if the CMMG bolt carrier will work w/ a FRT? Probably smarter to use a standard lower w/ a folding adapter but the folding lower seems a bit cleaner. |
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| Decided to build the upper and then figure out what to do for a lower. Have an 8" CMMG barrel and bolt carrier w/ the parts to build it coming. I'll figure out how that works. Will probably build it on an existing stripped lower I have. |
You must play the game. You can't win. You can't break even. You can't quit the game.
| I have a couple folding lowers. The only thing I'm not crazy about is that I'm stuck with their buffer. They don't take regular weights, but instead have one steel slug in them. The only way I've thought to add weight was to pull that and fill it with some tungsten bird shot. I had the same idea with the cmmg 5.7, but never got around to it. It would be a cool little pdw. |
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The adapters I've got take a normal buffer but have an insert for the bolt carrier. I ordered one of the plastic inserts to replace the metal one. I got the forend and need to install it Will shoot it w/o the folding adapter for reliability before I add complexity. Have thought about making it a SBR if it works, but w/ concealed carry laws I think I'm better off keeping it a pistol. Have too many projects running and am replacing a washer and dryer that went out. Then Home Depot screwed up the delivery/haul off. Everything is running slow right now. |
You must play the game. You can't win. You can't break even. You can't quit the game.
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