Bcm gas block set screws

[aleftwich22]

I know they are set at .460. I have a slr jig but obviously it’s a .450 not a .460. Opinions on does that .01 make that big of a difference or do I just do the one dimple and call it fine

[georgeib]

Do the 1 dimple, use the proper screws, use high temp thread locking compound, and it IS fine. Only reason you'd have to go further, like pinning the gas block for instance, is if the gas block were not going to be covered by the handguard.

[markm]

Shit. I just grab any larger drill bit and put a damned dimple on the barrel. So in my opinion, the difference doesn't matter. As long as the set screw can get a little bite into the circumference of the barrel, fine.

I like to stake the set screw in IF possible. Some seat too deep, so you have to go thread lock of some kind.

[titsonritz]

Put a single dimple opposite the gas port, that way you are not married to a specific gas block. FYI, every barrel I mentioned in your other thread came that way from the manufacturer.

Here is Mike of SOLGW telling you the same thing...

[prepare]

Barrel Dimple & Gas Block Set Screws

A barrel dimple does two things;

1. Ensures proper gas block alignment
2. Ensures the gas block does not move

To dimple your barrel the following tools will help to ensure its done properly:

A Dimple Jig (by SLR)
A 5/32 drill bit
A 5/32 drill bit depth limiting stop collar
A 5/32 transfer punch
A 5/32 washer

Image copy.jpeg


Place the dimple jig on the barrel and align the pointed set screw in the gas port then snug it down. The larger drill bushing screw should be directly opposite of the gas port.

Note:
Only one dimple is recommended.


Next, place the jig and barrel in a vice or drill press.


Image.jpeg


Now set the drill bit depth limiting collar and washer in the drill bushing and tighten the set screw. Then remove the washer.

*The thickness of the washer will be the depth of the dimple.

Before drilling place the 5/32 transfer punch in the drill bushing and give it a couple taps. Now its ready to drill.



Gas Block Set Screws


The correct Gas Block Set Screws are:
Alloy Steel Knurl-Grip Cup-Point Set Screw, Black Oxide, 10-32 Thread, 3/16" Long
McMaster-Carr P/N 90289A337

The proper Torque is 10-15 inch lbs. per BCM with Loctite 272

[the AR-15 Junkie]

Here is a video of the above /\ post.

https://www.youtube.com/watch?v=bRwPFtV4yN0

[prepare]

Here is a video of the above /\ post.

https://www.youtube.com/watch?v=bRwPFtV4yN0

Your video provides the best way to properly do a barrel dimple and is what I based my written instructions off of.

[Buckaroo]

Very helpful gentlemen!

[SteveL]

Here is a video of the above /\ post.

https://www.youtube.com/watch?v=bRwPFtV4yN0

Excellent video! Thanks for posting the link.