Cannot loosen set screws on BCM gas block

[LittleLebowski]

I've tried heat and penetrating oils. I've rounded a few hex or Allen keys. I'm not sure exactly what size of hex/Allen key to use. I've got an Easy Out kit en route but would prefer to get the screws out, would appreciate knowing exactly what size of wrench to use.

[blues]

LL, I don't know if this applies but I see this listing for their low profile gas block:


Set Screws are Steel 10-32 x 3/16 Knurled Cup Point

http://www.bravocompanyusa.com/BCM-Low-Profile-Gas-Block-p/bcm-lgb-750.htm


http://brdengineering.com/products/gas-block-set-screw

[WobblyPossum]

I've heard BCM really douses the screws in red loctite. Have you tried Bob Smith Un-cure? I've had good luck with it when it comes to loctite.
https://smile.amazon.com/gp/aw/d/B00...236_SY340_QL65 (https://smile.amazon.com/Bob-Smith-Industries-161-UN-CURE/dp/B0000DD1QS/ref=as_li_ss_tl?_encoding=UTF8&pi=AC_SX236_SY340_QL65&qid=1487006059&ref_=sxts1&sr=1&linkCode=ll1&tag=pistolforum-20&linkId=b0001a5f0dd449c412eb86f0ab643ee2)


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[orionz06]

LL, I don't know if this applies but I see this listing for their low profile gas block:



http://www.bravocompanyusa.com/BCM-Low-Profile-Gas-Block-p/bcm-lgb-750.htm


http://brdengineering.com/products/gas-block-set-screw

Typical wrench will be 3/32

[LittleLebowski]

I've heard BCM really douses the screws in red loctite. Have you tried Bob Smith Un-cure? I've had good luck with it when it comes to loctite.
https://smile.amazon.com/gp/aw/d/B00...236_SY340_QL65 (https://smile.amazon.com/Bob-Smith-Industries-161-UN-CURE/dp/B0000DD1QS/ref=as_li_ss_tl?_encoding=UTF8&pi=AC_SX236_SY340_QL65&qid=1487006059&ref_=sxts1&sr=1&linkCode=ll1&tag=pistolforum-20&linkId=b0001a5f0dd449c412eb86f0ab643ee2)


Not yet, but I ordered some yesterday.

[Lost River]

Try freezing it.

Then using a punch and hammer, give it a couple good hard taps.

Then try your Hex/Allen wrench.

[hiro]

Typical wrench will be 3/32

Being so small, there's a good chance the screws are deformed with the effort to remove. You might try the next size up or a metric key, maybe a 2.5mm will get some purchase but it's likely no key that small will loosen the screw without deforming.

If the top of the set screw is exposed try cutting a slot across it with a Dremel to enable the use of a flat blade driver.

Soak it with the nastiest penetrant and leave it soaking for days, topping up every few hours.

I think the easy out is likely your best bet but if the screw is a hard enough steel, it's not a guaranteed method.

[orionz06]

Being so small, there's a good chance the screws are deformed with the effort to remove. You might try the next size up or a metric key, maybe a 2.5mm will get some purchase but it's likely no key that small will loosen the screw without deforming.

If the top of the set screw is exposed try cutting a slot across it with a Dremel to enable the use of a flat blade driver.

Soak it with the nastiest penetrant and leave it soaking for days, topping up every few hours.

I think the easy out is likely your best bet but if the screw is a hard enough steel, it's not a guaranteed method.

The screws in question aren't that large in diameter so by the time you slot them with a dremel you're left with nothing to engage with a tool.

[hiro]

The screws in question aren't that large in diameter so by the time you slot them with a dremel you're left with nothing to engage with a tool.

Makes sense. Which also means no amount of torque from an allen key that size will remove them, has to be a chemical/temperature/drill solution. Might be easiest to just drill the set screws out, stopping just short of the barrel. There's a pretty good chance that either drilling or the easy out will damage the gas block.

[orionz06]

The amount of material engaged with a good extractor allows them to be rather successful. The manner in which they apply force to the fastener also helps. I'd bet the price of a gas block on them working.


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[breakingtime91]

Buddy had to drill his out. Bcm told him they douse in red loc tite, it took him awhile

[hiro]

The amount of material engaged with a good extractor allows them to be rather successful. The manner in which they apply force to the fastener also helps. I'd bet the price of a gas block on them working.
Yeah, I think you're right. That there's a socket in the top of the set screw is really gonna help, most of the time I've used easy outs is removing M5 bolts that have had the heads snapped off!

[SeriousStudent]

My understand is that BCM uses these:

Alloy Steel Knurl-Grip Cup Point Set Screw, 10-32 Thread, 3/16" Long; which is McMaster-Carr part number 90289A337

From their website: "Made from alloy steel, these set screws dig into hard surfaces for a secure hold. They have serrations on the cup edge that grip the material surface to resist loosening."

The little boogers have no-fooling teeth on the bottom to dig into the dimple in the barrel.

I have successfully used this to dissolve red Loctite: Bob Smith Industries Un-Cure.

https://www.amazon.com/Bob-Smith-Industries-161-UN-CURE/dp/B0000DD1QS/ref=pd_sim_328_7?_encoding=UTF8&pd_rd_i=B0000DD1QS&pd_rd_r=36RQRGT81Y2285S3WVF0&pd_rd_w=azElf&pd_rd_wg=H4xUl&psc=1&refRID=36RQRGT81Y2285S3WVF0

It's designed to dissolved super glue (CA) bonds.

Hope that helps.

[LittleLebowski]

No luck so far. I'm doing this in order to install an adjustable gas block to correct issues whilst shooting suppressed. I've already ran the gamut of different buffer weights, but a friend recommend changing out the extractor and/or bolt and seeing if that corrects the problem. I tried the factory size (3/32) and then a 2.5mm, both stripped or got smoothed by the screw.

[Rich@CCC]

LL,
You need the Marvel, BCM Buster hex key set made from Vibranium. A good tap with Thor's hammer will help as well.

[LittleLebowski]

My understand is that BCM uses these:

Alloy Steel Knurl-Grip Cup Point Set Screw, 10-32 Thread, 3/16" Long; which is McMaster-Carr part number 90289A337

From their website: "Made from alloy steel, these set screws dig into hard surfaces for a secure hold. They have serrations on the cup edge that grip the material surface to resist loosening."

The little boogers have no-fooling teeth on the bottom to dig into the dimple in the barrel.

I have successfully used this to dissolve red Loctite: Bob Smith Industries Un-Cure.

https://www.amazon.com/Bob-Smith-Industries-161-UN-CURE/dp/B0000DD1QS/ref=pd_sim_328_7?_encoding=UTF8&pd_rd_i=B0000DD1QS&pd_rd_r=36RQRGT81Y2285S3WVF0&pd_rd_w=azElf&pd_rd_wg=H4xUl&psc=1&refRID=36RQRGT81Y2285S3WVF0

It's designed to dissolved super glue (CA) bonds.

Hope that helps.

https://www.mcmaster.com/#90289a337/=16coi4k

[SeriousStudent]

Yup, that's them. Let me know if you want me to send you some for replacements.

[LittleLebowski]

Yup, that's them. Let me know if you want me to send you some for replacements.

Thank you, my friend. No luck so far, pursuing the "hopefully I don't have to replace them" route :cool:

[Andy T]

Had the same issue. Ended up giving my upper to a local smith who cut the gas block off.

[Clusterfrack]

If it's glued with Rocksett, you need to soak it in boiling water

[tsalagi88]

Buddy had to drill his out. Bcm told him they douse in red loc tite, it took him awhile
I'm the buddy. Can confirm. I left a jetboil stove under the gasblock til that dude was stupid hot and after breaking a couple nice allen wrenches I was able to get one out. Gave up on the last one. Took it to a smith and he was able to drill out the screw and save the gas block. After that experience if I ever want to make changes to my uppers that require gas block removal, I might use it as an excuse to buy a new upper. Good luck.

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[MistWolf]

I have successfully used this to dissolve red Loctite: Bob Smith Industries Un-Cure.

https://www.amazon.com/Bob-Smith-Industries-161-UN-CURE/dp/B0000DD1QS/ref=pd_sim_328_7?_encoding=UTF8&pd_rd_i=B0000DD1QS&pd_rd_r=36RQRGT81Y2285S3WVF0&pd_rd_w=azElf&pd_rd_wg=H4xUl&psc=1&refRID=36RQRGT81Y2285S3WVF0

It's designed to dissolved super glue (CA) bonds.

Hope that helps.

If it dissolves Super Glue, it's nothing more than acetone.

Get a hex Apex bit set and an Apex driver, which is is a screw driver that uses Apex bits. Clamp the gas block in a vise. Tap the Apex bit into the socket with a hammer. to help set the bit and loosen up the threads. You can hold the bit with a pair of Vise Grips if you don't want to whack on your bit driver. Put a quarter inch combo wrench over the bit. Lean hard on the bit driver while applying torque with the combo wrench. Start off slow. If it rounds off the socket of the screws, it's time for the EZ Out

[hiro]

LL, how's this one going?

[LittleLebowski]

LL, how's this one going?

On the back burner due to home improvements :D

[hiro]

A noble cause!

[cheshire_cat]

I was having difficulty getting a small set screw with a stripped head out of the TTI rear sight. The only thing that finally worked for me was to pound a small flat head screw driver into the head of the set screw. Then I was able to twist it out. Of course it ruined the set screw, but I had a replacement screw ready.

[tsalagi88]

Side question for this thread, but still relevant I think:

Any tips out there for correctly aligning the gas block once it's time to reinstall?

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[LittleLebowski]

Last night, the UnCure and heat didn't cut it, but I cut it :cool: Didn't harm the barrel either.

[LittleLebowski]

Side question for this thread, but still relevant I think:

Any tips out there for correctly aligning the gas block once it's time to reinstall?


Really check the gas key and gas tube alignment and feel.

[shane45]

You can try these. I know some people that use them.
http://www.brownells.com/gunsmith-tools-supplies/rifle-tools/gas-system-tools/ar-15-gas-block-aligner-prod68371.aspx


As for switching to an adjustable gas block, just did that on my .260 and had the same issue with one of the two set screws. But fortunately I have a mill.

[LittleLebowski]

You can try these. I know some people that use them.
http://www.brownells.com/gunsmith-tools-supplies/rifle-tools/gas-system-tools/ar-15-gas-block-aligner-prod68371.aspx


As for switching to an adjustable gas block, just did that on my .260 and had the same issue with one of the two set screws. But fortunately I have a mill.

Edit: never mind, posted too fast.

[LittleLebowski]

Really check the gas key and gas tube alignment and feel.

FYI, followed my own advice, and it worked great, hammered the shit out of that rifle suppressed today whilst tuning my new adjustable gas block. Nothing to it.

[shane45]

Which adjustable did you go with?

[LittleLebowski]

Which adjustable did you go with?

The Superlative Arms bleed off one (http://www.brownells.com/rifle-parts/gas-system-parts/gas-blocks/ar-15-adjustable-gas-block-625-solid-prod86813.aspx). It's my first adjustable gas block, all I know is that it fixed my BCM 11.5" SBR's malfunctioning with my SIG SRD 556 Ti can.

[LittleLebowski]

The Superlative Arms bleed off one (http://www.brownells.com/rifle-parts/gas-system-parts/gas-blocks/ar-15-adjustable-gas-block-625-solid-prod86813.aspx). It's my first adjustable gas block, all I know is that it fixed my BCM 11.5" SBR's malfunctioning with my SIG SRD 556 Ti can.

After running it hard and without issues, using M855, Tula, and reloads:


https://www.youtube.com/watch?v=4tntboO5qLY

[CuradoKid]

I know this is an old post, however, I just want to share my experience. I have a BCM low profile gas block and I used Loctite red (#271) on the set screws and DID NOT pin the gas block to the barrel. That was 2 years ago and now I wanted to change the handguard, so I had to remove the gas block. The loctite label says to heat the threads to 500 degrees to remove. I used a Wagner heat gun on high for about 6 minutes until my gas block started to turn a gray/white color. The sets screws easily came right off. Originally, I tightened them to 25/inch lbs, and never had any gas leaks or cycling issues. I hope this helps somebody one day.

[PensFan]

I know this is an old post, however, I just want to share my experience. I have a BCM low profile gas block and I used Loctite red (#271) on the set screws and DID NOT pin the gas block to the barrel. That was 2 years ago and now I wanted to change the handguard, so I had to remove the gas block. The loctite label says to heat the threads to 500 degrees to remove. I used a Wagner heat gun on high for about 6 minutes until my gas block started to turn a gray/white color. The sets screws easily came right off. Originally, I tightened them to 25/inch lbs, and never had any gas leaks or cycling issues. I hope this helps somebody one day.

My experience also. Heat gun did the trick.