Gas Block Instal Help

grimnar15 · Jun 9, 2020

I removed the A2 Sight Block that was pinned in place to replace it with a low profile double banded gas block.

As it turns out, both set screws line up almost perfectly with the grooves in the barrel that were taper drilled by colt.

Conventional thinking is that dimpling the barrel prior to set screwing the new gas block is in place is the right thing to do.

I am worried that because they almost nearly line up perfectly that dimpling (with a jig of course) will not guarantee a super tight fit.

Please let me know your thoughts.

outrider58 · Jun 9, 2020

The easy answer is try a different GB

How do you know when your block is lined up with the gas port?

grimnar15 · Jun 9, 2020

outrider58 said:
The easy answer is try a different GB

How do you know when your block is lined up with the gas port?

I used an SLR dimple jig.

atblis · Jun 9, 2020

Get a clamp on gas block. There are some arguments for them in general.

ETA: Have you considered just shaving down the FSB? Done right, it looks just fine.

outrider58 · Jun 9, 2020

grimnar15 said:
I used an SLR dimple jig.

Are you using an SLR block?

Do you have clearance for a clamp on?
They're actually better, precision wise. Less barrel stress.

grimnar15 · Jun 9, 2020

outrider58 said:
Are you using an SLR block?

Do you have clearance for a clamp on?
They're actually better, precision wise. Less barrel stress.

Couple of pictures.
-

John from MD · Jun 9, 2020

After a couple hundred rounds, the carbon will fill the gaps and it won't go anywhere. Just dimple it and locktite the screws.

clandestine · Jun 9, 2020

Use a clamp on instead. Use rocksett on set screws or clamping bolts. Not loctite.

DutchV · Jun 9, 2020

Do you still have the original FSB and pins? You could shave that down and reinstall it.

grimnar15 · Jun 9, 2020

clandestine said:
Use a clamp on instead. Use rocksett on set screws or clamping bolts. Not loctite.

Thank you.

grimnar15 · Jun 9, 2020

DutchV said:
Do you still have the original FSB and pins? You could shave that down and reinstall it.

I do, will give that a try as well.

outrider58 · Jun 9, 2020

clandestine said:
Use a clamp on instead. Use rocksett on set screws or clamping bolts. Not loctite.

DutchV said:
Do you still have the original FSB and pins? You could shave that down and reinstall it.

I would do either of these. I'm not digging what I'm seeing in those set screw holes.

atblis · Jun 9, 2020

If you must, using a mill and end-mill may work better. A drill bit will just walk on you. I am not a machinist, so take it for what it's worth.

grimnar15 · Jun 9, 2020

Thanks everyone for the recommendations. Decided to hack the original FSB with a dremmel and some elbow grease. Ugly as hell but no one will see it.

grimnar15 · Jun 10, 2020

It all went back together nicely as well. Will post pics later ...

Gas Block Instal Help

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