Member Login
Member Login
Member Login
OH, USA
|
Posted: 1/8/2021 4:15:33 PM EST
Hi,
Any secrets or recommendations on install BCM KMR barrel nut? I did try install last night and recommended max torque 40-50 ft-lb, but on 30 lbs I did strip nut very badly. |
|
|
TX, USA
|
Posted: 1/8/2021 4:31:32 PM EST
i always push the wrench towards the nut with one hand and use the other hand (and my body weight to a degree) to torque down.
|
|
|
|
Posted: 1/8/2021 4:31:39 PM EST
Pics? Did you strip the threading on the nut or upper, or did you strip the wrench notches out?
|
|
|
|
OH, USA
|
Posted: 1/8/2021 4:50:46 PM EST
Wrench notches. Now, impossible to install handguard.
|
|
|
|
Posted: 1/8/2021 4:59:07 PM EST
Quote History Originally Posted By yankee86: Wrench notches. Now, impossible to install handguard. Yeah, depending on the condition of it you may need to pick up a new barrel nut. Thankfully, they're cheap and in stock. If your wrench is FUBAR as well they've got that too. The main thing for putting it on is making sure that your pressure is being applied evenly. You want to have the receiver secured (I'm a fan of reaction rods, but a vice block works fine as well), hold the wrench flat against the nut with one hand, and then wrench down on it at a happy 90deg angle with the other. If you aren't all squared up and evenly applying force, you're just going to FUBAR another nut, and that's no fun for anyone. |
|
|
|
OH, USA
|
Posted: 1/8/2021 5:09:42 PM EST
Yes, I did purchase new one, last night. Wrench, I think is fine. To hold, I am using Magpul BEV Block.
|
|
|
|
Posted: 1/8/2021 5:15:00 PM EST
Quote History Originally Posted By berkeleygiraffe: i always push the wrench towards the nut with one hand and use the other hand (and my body weight to a degree) to torque down. This. I have done all this with all 3 of my titanium V7 barrel nuts to avoid stripping. |
|
|
|
MN, USA
|
Posted: 1/8/2021 5:32:51 PM EST
Quote History Originally Posted By yankee86: Wrench notches. Now, impossible to install handguard. 
|
|
|
OH, USA
|
Posted: 1/8/2021 5:58:46 PM EST
This was my next question, about Titanium Nut.
Thanks |
|
|
|
Posted: 1/8/2021 7:20:43 PM EST
Quote History Originally Posted By yankee86: This was my next question, about Titanium Nut. Thanks Not sure how many barrel nuts or castle nuts you've worked with, but if you don't keep forward pressure on the "teeth" then you will strip it. Titanium barrel nut is fine as long as you keep that pressure forward. |
|
|
|
USA
|
Posted: 1/9/2021 8:59:56 AM EST
I'm trying to wrap my head around how you stripped the nut. There are four slots for the BCM wrench to fit two bosses into. You stripped all four slots?
No disrespect intended, but if you have a hard time putting on the BCM barrel nut, should you be working on a gun that might blow up in your face? |
|
|
|
Posted: 1/9/2021 10:35:00 AM EST
Quote History Originally Posted By PineappleDevil: I'm trying to wrap my head around how you stripped the nut. There are four slots for the BCM wrench to fit two bosses into. You stripped all four slots? No disrespect intended, but if you have a hard time putting on the BCM barrel nut, shouldn't you be working on a gun that might blow up in your face? But aren't AR's like Legos?  |
|
|
|
MN, USA
|
Posted: 1/9/2021 11:02:59 AM EST
a gun that might blow up in your face Drama, much??? |
|
|
OH, USA
|
Posted: 1/9/2021 4:59:57 PM EST
[Last Edit: 1/9/2021 5:02:42 PM EST by yankee86]
cancel
|
|
|
OH, USA
|
Posted: 1/9/2021 5:01:42 PM EST
Quote History Originally Posted By PineappleDevil: I'm trying to wrap my head around how you stripped the nut. There are four slots for the BCM wrench to fit two bosses into. You stripped all four slots? No disrespect intended, but if you have a hard time putting on the BCM barrel nut, should you be working on a gun that might blow up in your face? Do you have any suggestions or recommendation? Or just dummy question? Yes, all four. I think, problem with wrench - it not going all the way in these notches. |
|
|
|
Posted: 1/9/2021 6:52:37 PM EST
[Last Edit: 1/9/2021 6:53:35 PM EST by GunnyFitz]
**SUBSCRIBED**
Seeking Handguards that will fit a BCM 14.5" Upper Receiver. The manner in which the BCM Handguards connect to the Receiver leaves me to believe that any other Brand Handguards will NOT fit with the same fashion. Only reason I'm looking for BCM MCMR (MLOK) is because I never should've bought the Upper with its Cheese Frater Quad Rail Handguards. Any advice ANY of you can provide - OR- A- Same size Handguard would be greatly appreciated. THIS is the part which leads me to believe they're different than other Brands.  Attached File Attached File |
|
|
|
|
Posted: 1/9/2021 6:59:09 PM EST
Depends on how well you can judge torque, but I've used this:
 The local specialty tool dealer had a torque wrench calibrator that he let anyone use to test their wrenches. It was always fun to see how close you were to a specific value without looking. |
|
|
|
|
Posted: 1/9/2021 8:23:02 PM EST
The kmr barrel nut is quite soft metal. Even with great seating, the wrench tends to deform the small barrel nut notches, and that interferes with the rail sliding on. It's better to have help with one person keeping the wrench flush. If mildly marred, try using a small, lightweight hammer to peen the surface flat, or V7 Weapon Systems sells a titanium barrel nut thats a bit sturdier.
As for install, try using a small rubber/plastic double hammer. Tap evenly on the front or rear ends of the rail to replace and remove, respectively. The taking off bit is hard as mallet strikes have to be done alongside the upper. It might take several tries to align the antirotation notches, and if I recall correctly, the assembly instructions even call for using flat metal gauges between the upper and rail for seperation by a cunt hair. As for the tightening nut, do not force the screw through the hole. It will slip through without tension when the rail is at the correct position. Readjust the rail -- usually more forward because of that gap between the upper and rail. |
|
|
|
OH, USA
|
Posted: 1/9/2021 8:52:41 PM EST
Quote History Originally Posted By check-raiser: The kmr barrel nut is quite soft metal. Even with great seating, the wrench tends to deform the small barrel nut notches, and that interferes with the rail sliding on. It's better to have help with one person keeping the wrench flush. If mildly marred, try using a small, lightweight hammer to peen the surface flat, or V7 Weapon Systems sells a titanium barrel nut thats a bit sturdier. As for install, try using a small rubber/plastic double hammer. Tap evenly on the front or rear ends of the rail to replace and remove, respectively. The taking off bit is hard as mallet strikes have to be done alongside the upper. It might take several tries to align the antirotation notches, and if I recall correctly, the assembly instructions even call for using flat metal gauges between the upper and rail for seperation by a cunt hair. As for the tightening nut, do not force the screw through the hole. It will slip through without tension when the rail is at the correct position. Readjust the rail -- usually more forward because of that gap between the upper and rail. Thank you. I will try your recommendation. Yes, barrel nut - pretty soft aluminum. What about titanium - much stronger or not a lot? |
|
|
TX, USA
|
Posted: 1/9/2021 10:28:56 PM EST
Quote History Originally Posted By GunnyFitz: **SUBSCRIBED** Seeking Handguards that will fit a BCM 14.5" Upper Receiver. The manner in which the BCM Handguards connect to the Receiver leaves me to believe that any other Brand Handguards will NOT fit with the same fashion. Only reason I'm looking for BCM MCMR (MLOK) is because I never should've bought the Upper with its Cheese Frater Quad Rail Handguards. Any advice ANY of you can provide - OR- A- Same size Handguard would be greatly appreciated. THIS is the part which leads me to believe they're different than other Brands. https://www.AR15.Com/media/mediaFiles/434956/20210109_182805_jpg-1772174.JPG https://www.AR15.Com/media/mediaFiles/434956/20210109_182835_jpg-1772176.JPG The cutout in the second pic fits a little metal tab that's the tab in the first pic. Same anti rotation tab for both just the bottom pic doesn't have it installed |
|
|
|
Posted: 1/10/2021 1:35:14 AM EST
Quote History Originally Posted By berkeleygiraffe: The cutout in the second pic fits a little metal tab that's the tab in the first pic. Same anti rotation tab for both just the bottom pic doesn't have it installed Quote HistoryOriginally Posted By berkeleygiraffe: The cutout in the second pic fits a little metal tab that's the tab in the first pic. Same anti rotation tab for both just the bottom pic doesn't have it installed Make sure it's the right orientation of the metal antirotation insert -- little tabs interlock with the front of the upper. There was a post here with someone doing a 180* degrees from correct orientation lol Originally Posted By yankee86: Thank you. I will try your recommendation. Yes, barrel nut - pretty soft aluminum. What about titanium - much stronger or not a lot? You're welcome! Just experience from a KMR! If an easier rail assembly is of interest, really consider the midwest industries ultralightweight combat rails. Bootleg and V7 Weapon systems make derivatives of the BCM KMR/Alpha rails, but I really wish BCM would make more magnesium rails like the KMR but mlok. Bootleg is unique for the hybrid mlok/picantinny or keymody/picatinny. Titanium should hold up well here. Even planning on ordering a spare for a Bootleg pickmod rail. |
|
|
|
OH, USA
|
Posted: 1/10/2021 1:41:01 PM EST
Quote History Originally Posted By check-raiser: Make sure it's the right orientation of the metal antirotation insert -- little tabs interlock with the front of the upper. There was a post here with someone doing a 180* degrees from correct orientation lol You're welcome! Just experience from a KMR! If an easier rail assembly is of interest, really consider the midwest industries ultralightweight combat rails. Bootleg and V7 Weapon systems make derivatives of the BCM KMR/Alpha rails, but I really wish BCM would make more magnesium rails like the KMR but mlok. Bootleg is unique for the hybrid mlok/picantinny or keymody/picatinny. Titanium should hold up well here. Even planning on ordering a spare for a Bootleg pickmod rail. Yes, I do like Bootleg one, but I already have BCM a while. Also, my first choice was SLR, but I did switch to BCM KMR. |
|
|
|
Posted: 1/11/2021 7:45:41 AM EST
Quote History Originally Posted By berkeleygiraffe: The cutout in the second pic fits a little metal tab that's the tab in the first pic. Same anti rotation tab for both just the bottom pic doesn't have it installed Thanks all. I've obtained some great info on this from a fellow Member (Doc) which was helpful on the BCM platform! |
|
|
|
GA, USA
|
Posted: 1/14/2021 8:19:06 PM EST
[Last Edit: 1/14/2021 8:19:39 PM EST by aloo]
I did this install Saturday. Keep forward pressure on the wrench to keep it in the slots. It's a tight fit sliding in the rail so I put my receiver in my freezer after the nut was on and then heated the rail with a hair dryer. Took 2 light taps to finish seating it on the nut and all was good.
|
|
|
|
Posted: 1/15/2021 12:48:20 AM EST
Quote History Originally Posted By aloo: I did this install Saturday. Keep forward pressure on the wrench to keep it in the slots. It's a tight fit sliding in the rail so I put my receiver in my freezer after the nut was on and then heated the rail with a hair dryer. Took 2 light taps to finish seating it on the nut and all was good. Just make sure you have the anti-rotation tab in there before tapping it on. Those handguards don't really like to come off once they've been put on.  Learned that one the "fun" way...
|
|
|
|
AR15.COM is the world’s largest firearm community and is a gathering place for firearm enthusiasts of all types.
From hunters and military members, to competition shooters and general firearm enthusiasts, we welcome anyone who values and respects the way of the firearm.
Subscribe to our monthly Newsletter to receive firearm news, product discounts from your favorite Industry Partners, and more.
Copyright © 1996-2021 AR15.COM LLC. All Rights Reserved.
Any use of this content without express written consent is prohibited.
AR15.Com reserves the right to overwrite or replace any affiliate, commercial, or monetizable links, posted by users, with our own.
