I built one from Brownells parts about a year ago. They offered a short run of full kits that I had to build for a buddy of mine, and fell in love with it. Mine came with a gas block that had chatter inside from radial interpolation machining of the gas piston hole, which caused a lot of blow by of gas. I ended up opening the gas port hole to compensate from 0.059" to 0.0665" for function. I notice on some videos, including yours, that the gas rings keep the soot of the forward portion of the piston until the gas rings. Mine doesn't, which is indicative of the gas leaking past the rings from the machining chatter. I may have to order another gas block in the future for better gas seal, and then buffer up in weight to slow it back down from being overgassed.
Oof, just finished the vid. Read my other comments. Essentially, bayonet lug won't fit, neither airsoft nor HK, without modification. A buddy of mine did this. His gunsmith reamed out the inside to a larger inner diameter, got it on, and still, the bayonet sits far forward enough the ring is sitting halfway down the slots in the birdcage.
I wanted one of these and I did a fair amount of homework. For the price after the handguard and a brn4 lower, it is cheaper than real HK(like almost everything else) but still very expensive. We are talking over $1600 + tax just for a complete upper. I guess I'm just not enough of an HK fanboi to pay for their civi rifle or to clone one. I just went with the 12" LMT piston shovelnose upper that has much higher quality in material and build. 7075 monolithic upper with excellent machining and durable finish, Cyro treated chrome lined 12" barrel is a perfect do-all suppressed length, adjustable gas block maintains same carrier speed suppressed or not, 2 screws to change barrel or swap bcg between DI and piston, the piston comes out the front without the need to take off the entire handguard.
HK416s have polymer dust covers so the magpul dust cover is fine, though I don't like the logo on it either. I don't think Brownells can get HK416 parts and MR556 parts anymore, they stopped carrying them with the BRN-4's introduction recently. IT might be HK side, it might be Brownells not wanting to compete with themselves, who knows. They probably can't get HK dust covers for their BRN4 line easily. Also, MR556 upper receiver assemblies that come with the tungsten powder buffer and buffer spring are about $1800 often, which is really not much more when you factor in their coming with the buffer and a handguard. I have not found a use for the BRN-4, except that the BCG is full auto cut and will fit in an MR556, that's very useful.
I have a German 416 upper receiver and I’m on my 3rd BRN4 barrel and bolt. I’m getting some sort of tolerance stacking issue where the locking lugs are beating themselves up.
I don’t know why anyone would pay for a MR556 especially since it’s not even a nitrided barrel. You either get a nitrided or a chrome option on the BRN-4. It’s a cool option and I’m glad Brownels is giving the market what it wants unlike the stuck up tards at HK.
If you're really going to build an M27, it's a giant pain in the ass. If you give up on the bayonet lug, it becomes super easy, still expensive. I have the lighter profile barrel. I'm going to sell it eventually, because it's a waste. Unless the profile of these is thinner than the muzzle of the light profile, this will NOT accept the HK bayonet lug without major modification to the lug. You can get IAR profile barrels from Nefarious Arms, but they're like $700 and not common. He makes them in batches like every 2.5 years, I was very lucky to get one. They accept the HK bayonet lugs (which are like $70 and available in various places brand new) with no modification and are also the same profile as the IAR in general on the rest of the barrel. A further problem is that this is not 16.5", so even if you get the bayonet lug on there, unless you get a very long muzzle device the bayonet will not fit correctly. These are 16.1". If you push the bayonet lug farther back to fit correctly, the bayonet lug will not be usable with the 11" quad rail handguard the M27 uses. There's no good way to use one of these brownells barrels, sadly, if you want a bayonet to fit.
I built one from Brownells parts about a year ago. They offered a short run of full kits that I had to build for a buddy of mine, and fell in love with it. Mine came with a gas block that had chatter inside from radial interpolation machining of the gas piston hole, which caused a lot of blow by of gas. I ended up opening the gas port hole to compensate from 0.059" to 0.0665" for function. I notice on some videos, including yours, that the gas rings keep the soot of the forward portion of the piston until the gas rings. Mine doesn't, which is indicative of the gas leaking past the rings from the machining chatter. I may have to order another gas block in the future for better gas seal, and then buffer up in weight to slow it back down from being overgassed.
Oof, just finished the vid. Read my other comments. Essentially, bayonet lug won't fit, neither airsoft nor HK, without modification. A buddy of mine did this. His gunsmith reamed out the inside to a larger inner diameter, got it on, and still, the bayonet sits far forward enough the ring is sitting halfway down the slots in the birdcage.
Been wanting to snag one of these, just have other projects. Really cool of them to come out with them. Love their BRN-180s....have 2 of them.
I wanted one of these and I did a fair amount of homework. For the price after the handguard and a brn4 lower, it is cheaper than real HK(like almost everything else) but still very expensive. We are talking over $1600 + tax just for a complete upper. I guess I'm just not enough of an HK fanboi to pay for their civi rifle or to clone one.
I just went with the 12" LMT piston shovelnose upper that has much higher quality in material and build. 7075 monolithic upper with excellent machining and durable finish, Cyro treated chrome lined 12" barrel is a perfect do-all suppressed length, adjustable gas block maintains same carrier speed suppressed or not, 2 screws to change barrel or swap bcg between DI and piston, the piston comes out the front without the need to take off the entire handguard.
O nooo! Tool marks..on a tool?!? 😂
HK416s have polymer dust covers so the magpul dust cover is fine, though I don't like the logo on it either. I don't think Brownells can get HK416 parts and MR556 parts anymore, they stopped carrying them with the BRN-4's introduction recently. IT might be HK side, it might be Brownells not wanting to compete with themselves, who knows. They probably can't get HK dust covers for their BRN4 line easily.
Also, MR556 upper receiver assemblies that come with the tungsten powder buffer and buffer spring are about $1800 often, which is really not much more when you factor in their coming with the buffer and a handguard. I have not found a use for the BRN-4, except that the BCG is full auto cut and will fit in an MR556, that's very useful.
I have a German 416 upper receiver and I’m on my 3rd BRN4 barrel and bolt. I’m getting some sort of tolerance stacking issue where the locking lugs are beating themselves up.
I don’t know why anyone would pay for a MR556 especially since it’s not even a nitrided barrel. You either get a nitrided or a chrome option on the BRN-4. It’s a cool option and I’m glad Brownels is giving the market what it wants unlike the stuck up tards at HK.
I hear they are not bad...ppl just complain
If you're really going to build an M27, it's a giant pain in the ass. If you give up on the bayonet lug, it becomes super easy, still expensive.
I have the lighter profile barrel. I'm going to sell it eventually, because it's a waste. Unless the profile of these is thinner than the muzzle of the light profile, this will NOT accept the HK bayonet lug without major modification to the lug.
You can get IAR profile barrels from Nefarious Arms, but they're like $700 and not common. He makes them in batches like every 2.5 years, I was very lucky to get one. They accept the HK bayonet lugs (which are like $70 and available in various places brand new) with no modification and are also the same profile as the IAR in general on the rest of the barrel.
A further problem is that this is not 16.5", so even if you get the bayonet lug on there, unless you get a very long muzzle device the bayonet will not fit correctly. These are 16.1".
If you push the bayonet lug farther back to fit correctly, the bayonet lug will not be usable with the 11" quad rail handguard the M27 uses.
There's no good way to use one of these brownells barrels, sadly, if you want a bayonet to fit.