question on BCA upper assembly

[tdbru]

does anyone know if bear creek arsenal uses a thread locking compound on their complete upper barrel nuts?

i'm taking apart my BCA upper to check/lap the upper extension face and to loctite 609 the barrel extension into the upper.

it seems to me i've been putting quite a bit of torque on the barrel nut with a long wrench and the barrel nut is not budging.

my next step is to use a propane torch to heat up the barrel nut a little to get it to expand relative to the receiver extension barrel nut threads to see if this will help me get the barrel nut loose.

if bca also uses either red or blue loctite (i.e. 242, etc) that would help explain why it's taking so much torque and the barrel nut is not even budging yet. and also in that instance the heat will be needed. i can see no evidence of a thread locker, but if it's used sparingly then it may not be visible.

just as an observation, on the barrel nut which uses standard hex wrench flats (30mm open end wrench) it looks like they put that nut on with enough force to distort the two driving edges of what ever wrench they were using. pushed up a wee bit of metal on the barrel nut.. why would anyone use that much torque? seems like either the wrench fit poorly (doubtful but possible) or they over torqued the heck out of the nut to get the handguard bolts to line up.

anyway, the propane torch is coming out as a next step, but if anyone knows if bca uses thread locker i'l appreciate knowing that as it would help explain why the nut is being so hard to loosen. i'll find out tonight either way i think. or something will break.

also if anyone has other hints for removing very tight factory installed barrel nuts, i'd appreciate hearing it.
thanks,
-tdbru

[A5BLASTER]

does anyone know if bear creek arsenal uses a thread locking compound on their complete upper barrel nuts?

i'm taking apart my BCA upper to check/lap the upper extension face and to loctite 609 the barrel extension into the upper.

it seems to me i've been putting quite a bit of torque on the barrel nut with a long wrench and the barrel nut is not budging.

my next step is to use a propane torch to heat up the barrel nut a little to get it to expand relative to the receiver extension barrel nut threads to see if this will help me get the barrel nut loose.

if bca also uses either red or blue loctite (i.e. 242, etc) that would help explain why it's taking so much torque and the barrel nut is not even budging yet. and also in that instance the heat will be needed. i can see no evidence of a thread locker, but if it's used sparingly then it may not be visible.

just as an observation, on the barrel nut which uses standard hex wrench flats (30mm open end wrench) it looks like they put that nut on with enough force to distort the two driving edges of what ever wrench they were using. pushed up a wee bit of metal on the barrel nut.. why would anyone use that much torque? seems like either the wrench fit poorly (doubtful but possible) or they over torqued the heck out of the nut to get the handguard bolts to line up.

anyway, the propane torch is coming out as a next step, but if anyone knows if bca uses thread locker i'l appreciate knowing that as it would help explain why the nut is being so hard to loosen. i'll find out tonight either way i think. or something will break.

also if anyone has other hints for removing very tight factory installed barrel nuts, i'd appreciate hearing it.
thanks,
-tdbru

No one uses thread locker on the receiver threads. You would hear off the front of the receiver if you put thread locker on it.

They just used a metric ton of torque. Best thing to do is put a cheater pipe on the end of your wrench and make sure your receiver is locked in with a reaction type rod, if it's in a clam shell type your most likely going to break it. Also order you a new handguard because that barrel nut is junk now.

[tdbru]

Thanks A5.

quick question, why would the barrel nut need replacing? just curious. it's steel. the upper is of course aluminum. i would assume grossly over torquing the barrel nut will destroy the upper threads long before the barrel nut threads are destroyed since Steel is typically much tougher/stronger than Aluminum. i was assuming when i get this apart that if something needs replacing it would be the upper before the barrel nut. hopefully a little heat will work wonders tonight.
thanks,
-tdbru

[A5BLASTER]

Thanks A5.

quick question, why would the barrel nut need replacing? just curious. it's steel. the upper is of course aluminum. i would assume grossly over torquing the barrel nut will destroy the upper threads long before the barrel nut threads are destroyed since Steel is typically much tougher/stronger than Aluminum. i was assuming when i get this apart that if something needs replacing it would be the upper before the barrel nut. hopefully a little heat will work wonders tonight.
thanks,
-tdbru

When you get it off. Try to put it back in the handguard. Very likely the high torque eggshapped the barrel nut.

I use to use the matrix arms handguards and their barrel nut is made just like the one you have. After installing and removing it a few times it eggshapped and no longer would fit the handguard without a ton of force used to get it back on.

[Lemonaid]

On my BCA it was the same as the o.p's, had to use a propane torch for the thread locker to break free, suspect Red loctite and on replacement it would need much more than 60 ft lbs, more like 80-100 for it the index properly. I would suggest getting barrel shims for indexing at a more reasonable torque setting.

[tdbru]

Thanks A5B and Lemonaid,
thanks for letting me know they use thread locker. the propane torch will come out tonight.

i will have some barrel shims on hand before re-installing.

wish me luck.
-tdbru

[Bobjones]

If you have access to an inrared thermometer, 500F should be adequate to break the bond on locktite red.

[tdbru]

well, propane torch didn't crack it loose. so it's in the freezer overnight and tomorrow i'll propane torch the nut again, and use a cheater bar on the wrench. i'll either get the nut lose of destroy something. quite unhappy with how hard BCA put that barrel nut on. no need for that. live and learn.
-ex BCA customer.
-tdbru

[tdbru]

got it. an hour in the deep freeze (aluminum has a higher TCE than steel, so should shrink faster than the steel) and it loosened right up. forgot how cold -40F is. made my hands hurt just carrying it from the freezer to the bench vise. barrel nut still round. handguard slides right on the barrel nut, no problem.

i'll let everthing defrost under a fan tonight and this weekend lap the upper receiver face.

thanks for your support guys. not sure why BCA put that nut on so frickin tight. but browsing the web it looks like lots of manufacturers do that.

whew.

now on to the next steps

-tdbru

[PVBoom]

Congrats

Was there evidence of any loctite or any other substance?

I was gonna post something different, I still will, for loctite.

There was a discussion about barrel bedding with loctite on the inside of the receiver.
It mentioned the difficulties/needing to use heat to loosen it for barrel removal.
Someone else said that loctite red/green? was susceptible to lateral shearing. So he would put the upper in a vice, muzzle down and use a 5/8 dowel and smack it with a hammer a few times and the barrel would slide out.

So I was going to propose (post freezing) using a hammer and tapping the barrel nut on the outside and front at different points (3,6,9,12) to try and fracture the loctite.

Anyways, congrats.

[Les Staley]

congrats on your disassembly success. Looking to change out a BCA barrel and re-use the other stuff, so this post has been informative. Did you use a home type freezer or something else, like a laboratory deep freeze? I think a regular freezer goes to around zero Fahrenheit. Thanks for clearing this up. Les

[tdbru]

PVBoom,
no evidence of loctite. just some oil/lube. once the barrel nut was off, the barrel slid out of the upper easily.

Les,
just a chest type deep freeze. set at -40F. not a big one. barrel + upper was almost as long as the deep freezer was wide.

because of the humidity here, when it came out of the deep freezer it instantly got covered in frost. so after i got everything apart, i put the barrel, barrel nut, and upper in front of a fan to dry off quickly to prevent rust from forming on the inside of the barrel. even though the bore was put away cleaned and oiled, i didn't want to risk water sitting in the bore for an extended period of time and causing rust in the bore.

thanks guys for the support.
-tdbru

[Les Staley]

tdbru, thanks! Ordered two barrels, a Faxon 18” with mid length gas tube, and a 16” Monster. They should be here next week. I’ll submit a full report on my projects ASAP!

[sqeezeatrigger]

What kind of freezer do you have??!!----- minus 40 degrees!

[sqeezeatrigger]

-40 degrees must be a misprint or you have one heck of a freezer!! Thats 72 degrees below freezing.

[tdbru]

nope, that's the recommendation for long term freezer storage. and most chest type freezers can get there. incidently -40F = -40C. yep, it's cold. made my hands hurt just getting the upper over to the bench vise. i should have thought about gloves. refrigerators/freezers will normally not be able to get the freezer part to -40F. usually 0F is about as cold as they go. but a true chest freezer can get very cold. meant for long term food storage. commercial meat locker storage freezers are set to -40 typically, or at least the ones i was familiar with growing up. try going into the freezer on a hot summer day to get some meat out for someone. you go from 95F to -40F. quite a shock. the reason they sent us kids in and didn't let the grandmas and grandpas go fetch their meat. and by the way, Jan nights in Nebr. where i grew up sometimes hit -40. North Dakota hits that temp in the winter regularly over night in Jan. makes one say darn, it's cold out tonight. probably why the population of Nodak is so huge.
-tdbru

[LRRPF52]

A heat gun is all you need for most thread lockers.

I’ve never had Red Loc-tite give me problems with a heat gun.

Rocksett is the one that will give you problems if you try to heat it. It requires submersion for extended time before it will release.

[SDW]

I dunno. I once used Permatex's green "Penetrating Grade" thread locker on a gas block. The kind of locker that's super runny and designed to be applied to parts after assembly. I figured, if it's not drilled for taper pins then this stuff will help. (Was a set-screw type attachment.) Boy was I right. A couple of year later I needed to get the barrel nut off so I could change out the hand guard. And I did remove the set screws before starting. Heat gun and tapping with a hammer would not get that gas block to move. It eventually took my MAP gas torch plus some POUNDING with that claw hammer to get it moving. Petty horrible. Ruined my gas block. I may as a well add that the gas block, a Troy Industries basic lo-pro, went on originally with a nice slip fit.

Learned a lesson. No more locking compounds under gas blocks. I've told this story to people and it's come back, "That's not possible. Everything melts at 400 degrees" or similar. Doesn't change the fact that mine needed to get effin' hot. And even then it was a mm by mm process.

[FLshooter]

I’ve changed barrels on close to a dozen of BCA uppers. Never had a problem loosening the barrel nut.I believe none of them were tighter than 60 pounds. The only AR15 barrel nut I ever had a problem removing was on my Colt 6920.That one had to be heated.

[Les Staley]

I ordered a reaction/torque rod from Brownells. Clamped the barrel nut between two parallels in a big vice, cracked her loose with a 1/2” breaker bar. No problem at all. Now if I knew the difference between a “mid” length gas tube and an “intermediate” length, I’d be golden..got the wrong one! Durn it!! Waiting again!