Hey Guys,

Just placed an order with Precision Fire arms on a Bartlein bull barrel in 6.5G. Well I got to thinking about it and do not know if the SLR adjustable Sentry 9 GB will fit under the Geissele MK4 13" rail. Barrel has the .936 thick gas section.

I can caliper my rail but SLR's site does not have the dimensions of the set screw style S9 on their site (site error showing the clamp on dimensions for set screw style). It appears the set screw style has a lil more clearance than the clamp on style.

Someone please let me know if you have tucked a SLR adjustable S9 under a Geissele MK4 rail. Pls tell me you have!

Not the Sentry 9 but my 7 fit under the MK4 with plenty of space. I think about .25" all around.

Yeah so I have an S7 under a MK4 now. Got home that night and broke out my caliper. No way a S9 is fitting under. I called Precision back and they let me change to a .750 sized barrel.