Gas Block Clearance

[netchemica]

I installed a BCM gas block on my Rainier match barrel. I could not see day light between the block and my CMR rail so I filed it down a few thousandths of an inch at a time until I was able to see daylight between them. However, that gap is tiny, I feel I would have a hard time sliding a piece of paper through there.

Is there a spec I can go by? Will this tiny gap affect my accuracy at all?

[Zspires94]

I don't think having a space between your block and your rail would cause any accuracy problems?

[netchemica]

I don't think having a space between your block and your rail would cause any accuracy problems?

I guess my question sounded a little weird. I was more concerned with how much space is required between the block and the rail. I have a very small gap between the two and I'm not sure if it's enough to not affect the harmonics.

[Hkbeltfed]

Judging by some ar15 barrel whip videos I've seen, you'll need much more clearance.

[aguila327]

I had the same issue with my 300blk build. My MI SS rail left very little clearance over my low pro bloc.

So far I haven't noticed any issurs but in all fairness I haven't shot it enough. Damn ammo shortage ;-)

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[netchemica]

Judging by some ar15 barrel whip videos I've seen, you'll need much more clearance.

That's what I was thinking as well. Is there a "rule of thumb" / clearance specification that I can follow? I have it down to almost the set screws. Seems like I'll have to shave those down also.

[AKDoug]

You have less clearance than this?

I think Stick said he used a Vltor lopro gas block. The Vltor and BCM I have are virtually identical in size. Do you have a picture?

[rvb]

I've been trying to get an answer to this recently myself due to a troy/vtac rail that isn't sitting centered around the barrel. A highpower high-master i spoke with suggested that a folded over dollar bill was enough clearance. Im looking forward to hearing other inputs.

-rvb

[netchemica]

You have less clearance than this?[IMG]http://farm6.staticflickr.com/5460/8908323074_38859c97e6_o.jpg[/IG]

I think Stick said he used a Vltor lopro gas block. The Vltor and BCM I have are virtually identical in size. Do you have a picture?

That's after I ground it down a bit.

The barrel doesn't seem to align properly. When I installed the gas block set screw into the dimple, the gas block made contact with the rail near the gas tube. I disassembled it, used a ruler to make alignment marks and saw that the dimple wasn't aligning the gas block properly. When I align it with the marks, it sits right, but it still droops a little. Looks like the gas block has a lot of room on top, next to no room on the bottom.

[AKDoug]

Any end view shots? How tight is the gas block when you slide it on the barrel? The barrel is .750" at the gas block area, right?