TRX rail backing plate almost touches the gas block

[dennisuello]

I have a Troy low profile gas block (on a middy barrel) and TRX extreme 11" rail. I installed the 4" rail underneath the gas block, so the backing plate of the rail almost touches the gas block. There's probably 1/64" or less of clearance. I can see the light, but with slight pressure applied I can close that gap.

Should I be worried of occasional contact affecting accuracy, or should I clearance a bit off the backing plate to clear the gas block?

[ra2bach]

I have a Troy low profile gas block (on a middy barrel) and TRX extreme 11" rail. I installed the 4" rail underneath the gas block, so the backing plate of the rail almost touches the gas block. There's probably 1/64" or less of clearance. I can see the light, but with slight pressure applied I can close that gap.

Should I be worried of occasional contact affecting accuracy, or should I clearance a bit off the backing plate to clear the gas block?

how slight pressure? can it make contact just by resting the rail or holding it in your hand? or do you have to push up on it with some force. do you use a tight sling?

fwiw, anything that touches the barrel, even slightly, from the time of ignition till the bullet leaves the barrel will have "some" effect on barrel harmonics and consequently the bullet path. the question is, how great of an affect and will that hurt or help the situation?

in some cases, "consistent" pressure can actually help the rifle's ability to group better, however, the POI will be changed and the sights need to be rezeroed. keyword here is "consistent" pressure. in your case, if the rail contacts the barrel occasionally, there could be loss of accuracy as well as POI shift.

secondary to all this is, is it "really" going to make a difference? first of all, how accurate is the gun to start with? how about from field positions? if you can't hold 5 minutes of accuracy from field positions, having a 1.5 minute gun won't mean squat.

the only way you're going to know if this actually means anything is to take the gun and shoot it from all positions and see what it does. if it shoots fine offhand or from sitting but starts throwing patterns 8" to the right from the bench, I'd say you got a problem. if, however, the only difference between your field position groups and rested groups is their size, while POI remains the same, then I'd work more on your skillz than worry about your rail.

hope this helped...