Did ADCO shave your FSB?
No, but if I ever do it again, they will. Took 3 local gunsmiths to get it right. Hopefully it’s all good now. I had mine shaved down as far as the photo on ADCO’s website. You pick on their menu what handguard it’s going under and BCM KMR is one. MCMR is the same diameter.
Lots of bad ideas happen in the firearms industry. They do it because people ask for it.
I’m pretty new to ARs, but this doesn’t surprise me. I’ll consider other options. If I re-barrelled, could I probably re-use my Colt bolt that has 1000-1500 rounds on it? Or time for new bolt and maybe cam pin?