Adjustible gas block does not fully clear the inside of the free float handguard for this build.

The contact is about as minimal as possible and the clearance is almost there to the extent that canting the handguard by an almost imperceptible amount would make it contact one side of the gas block or the other but not both.  

How much clearance should I be looking for to ensure the barrel is fully free floated and won't make contact with the inside of a rail in terms of ensuring accuracy?  

It is a 20" medium profile stainless steel barrel, with a .75 profile at the gas block, rifle length gas if that matters.  Current rail is about 13" and as you can see in the pic doesn't quite extend fully over the gas block.

I'm curious if I can remove a small amount of material along the top inner edge of the end of the handguard to provide enough clearance to ensure the barrel stays free floated and doesn't contact when fired assuming the current contact is so minimal its hard to tell if the handguard is actually making contact when the rifle is at rest, and how much material I would have to remove.  I like this rail and am hoping not to have to replace either it or the gas block if I can modify it slightly.

Thoughts?

IMHO it hurts nothing. I for sure know clearance the handguard will hurt nothing but resale value.

That's way too close for me. Did you buy the block and tube without first checking compatibility with the two different sizes to allow for flexing without the two hitting each other and disturbing harmonics??

Too close for my comfort too. Disturbance of harmonics via contact between the gas block and handguard causing is exactly what I'm worried about.  

And yes I got the parts without knowing whether they might hit each other causing this issue. First time I've had a "low profile" gas block come anywhere close to this issue so this possibility slipped by me. Seems to have more to do with the irregular shape of the gas block and the gas tube channel dimensions in the handguard in conjunction with each other. The handguard I had on hand from a previous build.

I've made that first mistake too, it's how I learned to research before buying


Try a Centurion or a SLR GB7, as they're both very small. Badger makes a very small one too called the TDX gas manifold, but has to be brought to smith machinist because of how it secures to the barrel. Criterion swears by the Badger blocks though. Both Centurion and SLR have pin holes too if you'd like to secure it to the barrel from any possible reliability concerns with torqueing

Edit: I think the centurion pin is a custom option if you buy one of their barrels.

Thank you for the helpful suggestions - I was leaning toward new handguard but this gives me another route to explore.  I will probably remove material from the handguard in the specific area on the inside end of the top of the channel with a dremel first to see if I can get sufficient clearance with minimal modification and see if that satisfies me.

Any recommendations on minimum clearance measurement I should go for whatever route I end up settling on?

My rule of thumb, is that I try to create flex by pushing the barrel to he top of the tube. If they touch or looks still too close for comfort, then it's still no bueno to me personally.

And you're welcome, I was trying to help you save that handguard and save some money, unless you're looking for a reason to get a newer tube. If so, Geissele, CMT, or KAC would work with enough clearance.