Gas Block Clearance

[Rogue111]

I'm putting together a SPRish rifle & am in the planning phase of the upper. I have ordered a WOA SPR 18" barrel & I would like to use the Syrac adjustable block with the YHM diamond FF rail over it. Based on the specs the clearance from the top to the gas block & the inner diameter of the handguard is 0.015" (if everything put together is concentric). I called YHM they said that's not enough space, I called Syrac they said its fine. What do you think, is 15 thou enough to allow barrel whip from a SPR profile?

Thanks

 

[Oleshep]

that is pretty tight.. If they touch during firing then you are going to have some big accuracy problems..

 

[wareagle700]

I would not be satisfied with that. I would want at least .100" of clearance from the handguard. Not sure how much the barrel moves but the clearances can change with different shooting positions.

 

[ORD]

Most mfgs call for a minimum of 0.05" clearance between the block and rails. Like wareagle...I'd still prefer a little more "wiggle room" personally, but 0.05" will get it done just fine. On the other hand...0.015" is cutting it DAMNED close and too close for my own personal comfort level. YMMV!!

 

[BobinNC]

Most mfgs call for a minimum of 0.05" clearance between the block and rails. Like wareagle...I'd still prefer a little more "wiggle room" personally, but 0.05" will get it done just fine. On the other hand...0.015" is cutting it DAMNED close and too close for my own personal comfort level. YMMV!!

+1

 

[Spiff034]

Handguards are pretty flexy. That's not enough.

 

[B.A.C.]

I'm in the same boat as you. I just bought a WOA 18" w/ rifle length gas system. I also have the Syrac gas block. For some reason it's really tight going on and I managed to scratch the barrel trying to put it on. I couldn't get it so I just gave up to prevent further damage. I plan on painting the barrel so it might just get covered up. They aren't very deep scratches, but nevertheless look like shit.

 

[Shanerbanner10]

Can anyone tell me what the clearance is like with a noveske recee 14.5" barrel, noveske low-pro gas block, and NSR rail? I am about to cut off the delta ring and the front sight post to install the low pro gas block.

 

[wareagle700]

Can anyone tell me what the clearance is like with a noveske recee 14.5" barrel, noveske low-pro gas block, and NSR rail? I am about to cut off the delta ring and the front sight post to install the low pro gas block.

Its plenty. I just set up my Noveske 18" SPR barrel with a 13.5 NSR rail and it had plenty of clearance. Same with my 16" RECCE with 11" NSR rail.

 

[Shanerbanner10]

Good deal, Thanks! I'll be running the 13.5" on a 14.5 upper. Shall be interesting.

 

[ORD]

Its plenty. I just set up my Noveske 18" SPR barrel with a 13.5 NSR rail and it had plenty of clearance. Same with my 16" RECCE with 11" NSR rail.

+1!!

The NSR was built to allow heavier, 0.875" gas block barrels to clear the rail with lo-pro gas blocks installed. I've yet to see ANY combo of lo-pro, SET SCREW gas blocks/0.750" barrels (like your SPR) that wouldn't clear with plenty of room to spare. The problem I HAVE seen (and it won't be an issue with the Noveske block) is clamp-on style blocks that have an addt'l amount on material on the BOTTOM portion of the block for the clamp screws. Additionally, some blocks, because of their unusual shape, can cause issues width-wise as the NSR has limited width room at <1.5" total. Again...you should be fine with the Noveske block and barrel combo you are going to be running.

 

[Oleshep]

I'm in the same boat as you. I just bought a WOA 18" w/ rifle length gas system. I also have the Syrac gas block. For some reason it's really tight going on and I managed to scratch the barrel trying to put it on. I couldn't get it so I just gave up to prevent further damage. I plan on painting the barrel so it might just get covered up. They aren't very deep scratches, but nevertheless look like shit.

If you heat the block up some with a heat gun or in the oven on a low temp setting it shoudl slide on easier...

 

[Rogue111]

Help me out here... the specs of the .750 Syrac adjustable block states from the center of the bore to the top of the block measures .860". The inner RADIUS of the YHM diamond FF handguard is .875, leaving .015" clearance, right? The YHM rail has one of the biggest inner diameters on the market, yet some reviews on Midways website and threads on other forums state users have had success running the gas block under rails with a smaller ID than the YHM, am I missing something?

 

[smokebomb]

The only point of contact could be on the very top, the way the YHM diamond rail is designed has no recess under the rail portion. Assemble it. If the block is closer to the rail than you desire, slightly recess the inside of the rail portion. You will have no ill effects on the tube taking 0.04" off the underside of the rail. A needle file or dremel bit #952 is ideal for this purpose.

 

[427Cobra]

A Syrac set screw gasblock fits just fine with plenty of room with my 15inch NSR, I don't think the clamp style will work