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View Full Version : Anyone have issues with set screws on the BCM ELW barrels?


ABNAK
10-11-14, 09:46
Was reading where the ELW barrels have the gas block held in place by set screws. That is usually universally poo-poo'd on here, and quite frankly something I'd never considered using on a gas block (prefer it pinned). I like the idea of the ELW profile and it's constant taper but am hesitant to trust screws > pins.

Any feedback or thoughts on securing the gas block with set screws?
mikejg
10-11-14, 09:57
All BCM barrels with low pro gas block are set screwed, not just ELW. I've never heard of anyone having an issue with a BCM gas block coming loose.
ABNAK
10-11-14, 10:04
All BCM barrels with low pro gas block are set screwed, not just ELW. I've never heard of anyone having an issue with a BCM gas block coming loose.

I thought the lo-pro blocks on standard profile BCM barrels were pinned?
SpeedRacer
10-11-14, 10:06
I've never had a set screw gas block come loose on a properly dimpled barrel, BCM included. You'll be fine.
six8
10-11-14, 10:06
They're damn near impossible to remove too
scoutfsu99
10-11-14, 10:29
All BCM barrels with low pro gas block are set screwed, not just ELW. I've never heard of anyone having an issue with a BCM gas block coming loose.

I recently fixed one on my BIL's rifle. It was a 16" midlength factory BFH upper.
thopkins22
10-11-14, 10:30
I thought the lo-pro blocks on standard profile BCM barrels were pinned?

Nope. I think the general consensus is that if it's installed properly AND covered by the rail, you're unlikely to ever have a problem. But their low-profile gas blocks are definitely not pinned.
ABNAK
10-11-14, 10:50
I recently fixed one on my BIL's rifle. It was a 16" midlength factory BFH upper.


Had it come loose ?
Jwknutson17
10-11-14, 10:54
The only low pro BCM gas block that I have thats pinned is from my Kino upper. It does also have a screw set with the barrel dimpled. All the other uppers I have that are BCM are all screw set. Never had an issue. Ive bent a few allens trying to get those suckers off. Heat and some snap-on allens are usually the only efficient way to get em off.
markm
10-11-14, 18:20
They're damn near impossible to remove too

This is the only problem I'd suggest with the BCM set screws.
308sako
10-11-14, 19:11
I have a 14.5 Enhanced LW BCM due here Monday and have chosen the Viltor clamp on .625 gas block. I prefer the even pressure of that style to the pin point pressure of the set screws on a thin barrel. Properly done they all work very well however.

Can't wait to carbon up the works and see how this profile shoots.
Robb Jensen
10-11-14, 20:31
If you can get Loc-Tited BCM gas block set screws to loosen by just shooting the gun then you're one bad MF'r. I have to use a MAP gas torch to get them REALLY hot to loosen them.
Press Check
10-11-14, 23:40
I broke two hex wrenches removing the set screws, and these were quality tools.
scoutfsu99
10-12-14, 00:15
Had it come loose ?

Roger. His AR turned into a single shot rifle. Initially we tried different mags then a different BCG just to eliminate things. It would load fine, fire, but not eject the expended round. I tried this multiple times. I pulled off his Troy rail and moved the low pro gas block forward by hand. He had no problems shooting prior to this day.

He bought (I bought it for him) second hand but to our knowledge, it is a factory upper. Factory BCM upper marked BFH & BCM stamped barrel. Since it was bought used, it could have been a home build but I don't think it is. I can't find the ad but I bought it either here or Arfcom. I brought it to the house, set it back up and loctited the set screw. I took it back to the range and put 2 mags through it just fine.

I chalked it up to one of those things that happens. I don't blame BCM or doubt their products. Nothing is perfect and things can/will fail.
cd228
10-12-14, 03:12
I asked Phreakish about this about a month or so ago. he said that he had not seen one come back the BCM due to a loose gas block..

Is staking those screws an option?
krichbaum
10-12-14, 06:43
As was mentioned, if the block is covered by the rail and installed properly I don't see a need to pin it...and I actually prefer that they not be pinned. Set screws with dimples and the right threadlocker work fine.
BufordTJustice
10-12-14, 09:40
If you can get Loc-Tited BCM gas block set screws to loosen by just shooting the gun then you're one bad MF'r. I have to use a MAP gas torch to get them REALLY hot to loosen them.
I usually pin mine just because OCD. However, I just removed one I installed for a friend using high temp (450 degree) red Loctite (permatex brand). I used a butane torch and ended up giving up and drilling the screws out after I broke my second hex wrench.

If the surfaces of the threads are clean and prepped with alcohol prior to application, and the threadlocker is allowed to cure for at least 24 hours, it's ON THERE.

To the OP, I would wager their upper was not assembled by BCM. They use Loctite 271 IIRC and that stuff is very difficult to remove.

EDIT: You have to maintain steady heat exceeding 500 degrees to get it to yield. Even then, it will still have a percentage of its original strength to retain the fastener.

Further, I use McMaster-Carr knurled cup tip set screws to put some gravy on top. For light use, I bet those screws would hold without any threadlocker at all.
teutonicpolymer
10-12-14, 18:51
Set screw versus pinned? How about none of the above- I am a fan of the Vltor clamping gas block
Singlestack Wonder
10-12-14, 18:55
BCM SPR Uppers have the gas blocks pinned. I wish BCM would offer pinning on other uppers.
BufordTJustice
10-12-14, 19:12
Set screw versus pinned? How about none of the above- I am a fan of the Vltor clamping gas block
The screws used in a clamp on GB are placed under a bending force in addition to the normal forces a screw experiences upon being torqued down. Also, the screws typically swage out the threads in the gas block if tightened too much. They have not had a strong track record during hard use here on the board.
teutonicpolymer
10-12-14, 19:27
The screws used in a clamp on GB are placed under a bending force in addition to the normal forces a screw experiences upon being torqued down. Also, the screws typically swage out the threads in the gas block if tightened too much. They have not had a strong track record during hard use here on the board.

Wasn't there a thread on this where a number of people observed that clamping is better than set screw? The bending force would act to ensure the bolts don't back out and I don't think people remove these enough to worry about runining the threads.
C4IGrant
10-12-14, 21:12
Was reading where the ELW barrels have the gas block held in place by set screws. That is usually universally poo-poo'd on here, and quite frankly something I'd never considered using on a gas block (prefer it pinned). I like the idea of the ELW profile and it's constant taper but am hesitant to trust screws > pins.

Any feedback or thoughts on securing the gas block with set screws?

I have the ELW-F barrel and have run it through D4 and Mac training classes with zero issues.

C4

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C4IGrant
10-12-14, 21:15
BCM SPR Uppers have the gas blocks pinned. I wish BCM would offer pinning on other uppers.

No need.



C4

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Iraqgunz
10-13-14, 02:33
1. A simple search would have revealed numerous discussions about this. Since BCM and many others use set screws with dimpled barrels should it be an issue it would revealed itself many times over.

2. Not sure why you think people poo-poo this set up. It's clamp on type blocks that have issues.

3. When done properly, it's virtually impossible for set screws loosen during use. When it happens, it's usually from companies that don't dimple barrels, don't use Loctite and use crappy materials.