Brownell's BRN-180 upper

Discussion in 'Rifle Country' started by wiscoaster, Nov 28, 2021.

  1. wiscoaster

    wiscoaster Member

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    Anybody been shooting their AR with a Brownell's BRN-180 upper? They have them on sale, their new Gen 2 verson, and I ordered the 16 in. sporter model yesterday. Video reviews are favorable, but if any real people here have any advice for me, please shout it out!! Thanks...
     
  2. BigBlue 94

    BigBlue 94 Member

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    No but i want one in pistol form... Kinda funny i started envisioning the dual rod recoil mechanism as a way to delete the buffer tube. Then discovered it had been done many years ago lol
     
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  3. CapnMac

    CapnMac Member

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    Like the AR-18/180, it's a piston-driven system without a protruding recoil spring.
    The basic design using a couple of rails with springs has been copied into many other weapons.

    If the BRN-180 is as nice as the 605, it will e a good upper.
     
  4. JShirley

    JShirley Administrator Staff Member

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    I personally am going for the Foxtrot Mike FM15 Gen 2 currently available from Aim. I have invited Paul Noonan from Foxtrot Mike to join the discussion, if he wants to explain the difference between the systems.

    ~John
     
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  5. FM PRODUCTS

    FM PRODUCTS Member

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    Greetings all, we helped develop the BRN-180 for Brownells after we developed the retro BRN-10 for them. We were tasked with adhering as closely as possible to the AR-18 and have it be capable of using a standard AR15 lower. Most companies doing current piston uppers successfully have used the AR-18 as a starting point. The BRN-180 is s short stroke gas piston upper, with a trunnion that replaces the standard barrel extension in an AR15. The BRN-180 has a recoil modifier attached the the rear of the upper. Our upper uses a recoil modifier that threads into the buffer tube thread on a standard AR15 lower. This allows the recoil to be absorbed by the buffer tube loop on the AR15 lower (kudos to Eugene Stoner).

    The FM15 Gen 2 is a direct impingement upper, with greatly reduced mass (small carrier, no buffer or buffer tube). The reduced mass and design allow for unique recoil impulse that is very flat shooting. We started developing the gun several years ago and spent the last 3 months of production testing mainly shooting suppressed. We found they run well suppressed using anemic steel cased ammo well (imagine that), but had to increase the gas port a little to run anemic ammo unsuppressed.

    There is a nested recoil spring that allows us to have an integrated recoil system in the upper, allowing consumers to use a folding adapter. The outer spring is 12 plbs and coiled clockwise. The inner spring is 8 plbs and is coiled counter clockwise. The Bolt carrier is supported by the upper receiver bore, and also the gas key is unique, and there is a recoil rod that goes through a hole in the gas key, allowing the gas key to ride on the rail, and guaranteed there is no carrier tilt.

    There is an improved round cam pin, and a pretty interesting gas block design. We drill the gas block port from the top. When we assemble it, we test fit the gas tube in the gas block by installing it upside down. Then we can look through the hole at the top of the gas block and confirm the ports are aligned. Then we remove the gas tube and slide the gas block on the barrel. We look down the gas block and confirm alignment. once we confirm that, we pin the gas tube to the gas block, then install the gas block on the barrel.

    We keep a very tight fit between the gas block and barrel, and use (2) 1/8" pins to attach it to the barrel. There is an interlocking feature between the barrel and gas block, to guarantee good alignment. We use a gage pin through one of the 2 holes in the gas block to guarantee alignment before driving in the 1st 1/18" pin.

    The barrel has 6 flats cut on it at the chamber end of the barrel. pretty much every company making Ar15's uses a 10-20 ton press to clamp down on a round barrel, and use 125-150plbs of torque to install the barrel extension. We use the 6 flats machined into our barrels, and slide it down into a 1" plate with a mating shape cut into it. Then we slide the barrel into the plate, and torque the barrel extension, this ensures we dont crush the soft barrel material when installing a barrel extension.

    The upper can be dissembled with a punch, but I like to use a screw driver (seems easier to me). There is a 20 plb recoil spring ready to jump if you are not careful, so wear eye protection when disassembling them. The upper and handguard are seamless and mimic a monolithic upper. there is an interlocking feature between the upper and handguard, that guantees the barrel nut wont come loose after the handguard is installed. The handguard clamps down on the barrel nut, and interlocks with the upper.

    The barrel nut and handguard are kept to a tight fit, and the barrel nut is long to provide good torsion support over the length. It is held in place with (2) torx socket head cap screws. They allow the handguard to be removed many times without stripping the screws, and make torqueing the screws very simple.

    Another unique feature is the taper lock barrel nut. The barrel nut and barrel are made in the same Okuma Twin Spindle lathe. There is a taper on the inside of the barrel nut, and the on the outside of the barrel (in front of the chamber). When the barrel nut torques down, the load is distributed over a large surface area, and this helps with keeping the concentricity between the upper and barrel.

    Where the BRN-10 has a 2 position adjustment (suppressed and unsurpressed), we found the Gen 2 ran well suppressed so we opted to offer a suppressor recoil spring in order to offer the Gen 2 at a better price point.
    The guns run well suppressed, but if people ping us we generally send them a spare suppressor recoil spring. The main benefit of a Supressor recoil spring is it slows down the carrier a little.

    There were challenges getting the BRN-180 and gen 2 to market. Any time you launch a new product, the 1st 1000 customers who try it, are critical to making improvements to the gun. We did extensive testing on the 2 platforms, but consumers using varied combinations of ammo, parts, magazines really allow you to bring a more mature product to market.

    How important is running steel cased ammo to consumers?

    We have found steel cased (and even some Russian brass) is anemic. Some ammo is about 15% less fps using a chronograph, thats a big difference, which is why many companies have guns that are over gassed (so they cycle w anemic ammo). I think its harder to make a gun run steel cased 5.56 than to make one run suppressed. With our 9mm platform, they love steel cased ammo, but a blow back gun is very different than a DI 5.56

    Full disclosure, we have shipped around 1000 units between Aim and Brownells and have found 2-3 units that appear to be undergassed. We resolved those customers concerns, but have not been able to get the uppers returned for us to evaluate. We had used an off the shelf gage to check the gas tubes, but it did not identify gas tubes that were a little undersized. FM had been getting gas rings from CSS, and had not been inspecting them. We have already added a step to qualify the diameter of the gas tubes and gas rings and have not see any issues since. We Likely anemic ammo may have also played a part in this, I will follow up on this when I get those units back.

    Hope this info is helpful, I will do my best to keep an eye on this post, please be patient as we are jammed up running the shop etc. Best way to reach us is email [email protected] we offer customer service support 7 days a week too.
     
  6. JShirley

    JShirley Administrator Staff Member

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    Paul, thanks for taking the time for that detailed explanation. I'm looking fwd to my FM15, and will report back to the board. :)

    ~John
     
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  7. MechAg94

    MechAg94 Member

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    Thanks for the write up. I saw the FM15 emails from Brownells, but didn't know much about it. I was eyeing the new BRN-180 sport upper for 2022, but may have to look at this one also.
     
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  8. wiscoaster

    wiscoaster Member

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    Ordered Saturday, invoice email received yesterday (Monday) morning, shipment / tracking notice email received yesterday evening; delivery guy shows up with a box at 11:09 am today. Never seen anything like it. (3 - 5 day standard shipping was selected)
     
    Last edited: Nov 30, 2021
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  9. wiscoaster

    wiscoaster Member

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    The BRN-180 bolt release does not work if you have a BAD lever installed. The BAD lever attachment housing somewhat restricts the range of motion of the lower's bolt release button. Apparently the BRN-180 requires a more positive release. I have two other uppers that work properly with my BAD lever installed, and I like using it, so that's a bit of a disappointment, but not a show-stopper. The bolt release works fine with the BAD lever removed. Perhaps the OEM can look into fixing this for the next Gen.
     
    Last edited: Nov 30, 2021
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  10. JShirley

    JShirley Administrator Staff Member

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    Pics?

    It'd be great to see the upper and the BAD issue.

    John
     
  11. wiscoaster

    wiscoaster Member

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    No pics of the BAD issue. I already removed it and I'm not going to put it back on just to take a pic. The issue is as described above. The BAD lever doesn't depress the bolt release far enough to cause enough movement of the bolt hold open lug to release the BRN-180 bolt. The reason it doesn't depress the bolt hold open farther is because of the BAD lever's attachment housing takes up space behind the bolt-release button and therefore reduces its lateral range of motion. The BAD lever works fine with both my .223 and my 300 AAC uppers. I don't know why it works fine with them but not with the BRN-180. OEM or Brownell's should have more resources to diagnose a remedy than I have. It's just a bit disappointing because I have an ambi safety lever installed and with the BAD lever and an after-market charging handle on my uppers I had complete right-sided control of the rifle. Not a biggie; just have to modify my manual of arms....
     
    Last edited: Nov 30, 2021
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  12. wiscoaster

    wiscoaster Member

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    OK, pics ... hah!! I think I've got something for you. As you can see comparing the two pics below the bolt stop engages the bolt more deeply on the BRN -180, thereby requiring more movement in order to disengage it:

    IMG_2239.JPG

    IMG_2281.JPG

    I hope that's helpful. Those pics were not easy to take. I don't have the three hands required. o_O

    FWIW the lower started life as a Ruger AR-556, and I think the bolt hold-open is still original (though not much else is). ;)
     
    Last edited: Nov 30, 2021
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  13. JShirley

    JShirley Administrator Staff Member

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    Thank you!
     
  14. FM PRODUCTS

    FM PRODUCTS Member

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    shoot me an email [email protected], inlcude your address I will send you a suppressor recoil spring
     
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  15. FM PRODUCTS

    FM PRODUCTS Member

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    We machined our lowers and uppers to work w a BAD lever btw. Its super nice feature w a gun that has a forward charging handle
     
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  16. wiscoaster

    wiscoaster Member

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    OK, I'll do that. I'm guessing the suppressor recoil spring has less tension, thereby exerting less force on the bolt, and making the bolt stop easier to move? I'll let you know how it works out. But question: do I also then adjust the gas setting?

    Going out to the range this afternoon to fire first shots. :)
     
    Last edited: Dec 1, 2021
  17. wiscoaster

    wiscoaster Member

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    Range report: rifle shoots just fine. No issues. Zero malfunctions. Needs another range trip to tweak the iron sights and the red dot optic -- wasn't my primary mission today, but so far accuracy looks pretty good.
     
  18. BigBlue 94

    BigBlue 94 Member

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    I love living close to Midway and Brownells. Like 300 miles from either. Next day normal ground shipments are the norm. Placed an order monday with brownells and have yet to get a shipping confirmation.
     
  19. FM PRODUCTS

    FM PRODUCTS Member

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    Thanks for the update!
     
  20. JCooperfan1911

    JCooperfan1911 Member

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    I’ll take your word for it.
     
  21. CapnMac

    CapnMac Member

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    You should. Got to drive my bro's build just today. Was a nice rig, especially set up in full AR-18 guise (barring fun switch). All the good ergo of an AR, too. The folding stock is very sexy, and the balance is not too far forward, unlike on a 416.
    And while very nice, I'm still saving my pennies for a WWSD carbine first.
     
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  22. JCooperfan1911

    JCooperfan1911 Member

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    Love what Ian and Carl did with that project. What a superb build.
     
  23. Elkins45

    Elkins45 Member

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    I bought one of the GWACS lowers mostly as a gag when someone was clearing them out for $89. I put a 16” stainless pencil barrel upper with a Leupold 1-4X compact on it. It’s my favorite AR except maybe my 300 Blackout SBR. An under six pound rifle is an absolute joy to carry and shoot.
     
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  24. JShirley

    JShirley Administrator Staff Member

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    I talked to Aim this morning. They said they haven't shipped my assembled pistol because FM is replacing all the uppers with ones that have had the gas port enlarged slightly. From my conversations with Paul, this doesn't seem to have been a problem if users only fired 5.56x45mm, but could have taken more rounds to break in if the shooter was using .223 and not suppressing it. Cheap anemic steel-cased .223 would have made the problem worse.
     
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  25. JShirley

    JShirley Administrator Staff Member

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    I would like to give more of an update, but the Postal Service has lost my upper. Paul did share a video that explains the adapter (TLDW: you install the adapter instead of the buffer tube). Yes, that does mean a bit more work than just slapping it on like a standard AR upper, but removing the need for the buffer tube is the whole point, right?

    John
     
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