The best you can buy - Faxon Firearms Match 300 BLK Barrel

Great barrel but it’s best to get a Faxon gas block and tube from faxon when you buy this barrel because faxon barrels have e pretty large gas whole that exactly matches their gas block’s whole other wise you will have to line up the gas whole perfectly if you use a non-faxon gas block or risk a gas leak or possibly not getting enough gas through your gas tube which might cause a failure to cycle. It’s ok to use a non-faxon gas block but your alignment will have to be precise so save yourself the trouble and just pair faxon barrels with faxon gas blocks and gas tubes.