2024年12月14日 · Hk416A5/m27/brn-4 m27/black ops defense clone bayonets. A5 and black ops clone are to large and are sized for the heavy profile of the mr556 profile thickness. M27 and brn-4 m27 clone are the same size and both work.

2024年10月6日 · No brn-4 op rod issue until I opened gas port to 1.8mm to get last round hold open. Op rod over traveled compressed to far blew piston rings on 2 different pistons. I replaced with a second brn-4 op rod and it bent to the ejection port side and deformed my tombstone face slightly. Tested fit the bent op rod in a mr556 and hk416 receiver.

2021年1月1日 · MR 556 / BRN-4 Bolt Review and Survey Jump to Latest 5.1K views 15 replies 8 participants last post by Gatsby177 Feb 7, 2021

2024年11月11日 · Have you disassembled the BRN-4 BCG. I had a firing pin spring squeeze into the gape between firing pin head and the wall of bcg interior channel. I had a couple failures to fire and did a complete disassembly. Replaced with hk …

2019年4月15日 · I have a BRN-4 lower from Brownells and intend to have a person engrave the lower to make it a semi 416D clone, to match an HK upper I recently purchased. I have a simple (albeit dumb) question for those of you with the BRN-4 lower. Will a standard parts kit work fine, or are there other HK specific parts or components that will only fit.

2024年1月3日 · I’ll contact Brownells and give them the hardness numbers encase they want to get other BCG’s tested. Any how the BRN-4 BCG worked great until the 450-500 round mark. I think it’s a solid design but the heat treating needs to be adjusted.

2021年1月4日 · I can tell you from experience that If you start cerakoting parts and using genuine HK parts you'll end up with in arms reach of just flat out buying a used unmodified stock MR556 upper and topping off a BRN-4 lower then add the HK, Geissele, etc, etc. bling later on.

2021年12月26日 · ”BRN-4 Bolt Carrier Group is designed to be compatible with standard AR-15 or M16 type triggers. Common AR-15 aftermarket drop-in, cassette or mil-spec type triggers will work with the BRN-4 BCG.”

2020年12月22日 · Yeah I was considering a spare as well but I kept talking myself out of it because I have a few BRN-4 lowers already that I haven't touched as it is. Yes I saw that one. If I were interested in a lower I don't know if I'd want to pay the premium because the 416 upper is included if I didn't need it.

2023年11月12日 · My 10.4" BRN-4 barreled upper shoots about 1.5-2" groups with IMI 77gr razorcore and an unmagnified eotech at 100 yards. IMO that is perfectly acceptable for what I intend to use the rifle for. I would absolutely trust that setup with my life. It has been a problem free upper for the 2k rounds already have through it.