I had a 15" evo on a 6.8 build I traded away that I could never get tight and I think I've found out why.
In another thread Andew said:
Quoted:
Hey guys thanks for stepping in here. you are all correct. First double check to make sure the thermal bushings are installed correctly. The full holes should be at the top next to the gas tube and the half holes at the bottom. If this is done correctly slide the rail back on and clock it properly. Then hold pressure downward on the muzzle end of the HG exaggerating it toward the barrel (this makes sure it aligns perfect with the upper receiver when you tighten it). Tighten each screw evenly until the clamp gap is completely closed (It will feel like a lot but the wrench is little). While you are tightening it you will feel the muzzle end push up against your hand. the rail should now be perfectly in line and tight. Now you can tighten the set screw at the 6 o'clock position. Give me a call anytime if you have any questions. 603-355-3903
Thanks,
Andrew Dreher
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I was afraid to tighten mine down enough to close the gap because the ears were bending. But you said above to tighten them until they touch basically, and I've also seen a rifle in the Sig Pro Shop in NH that has them touching as well. I'm assuming the problem with my last rifle was that I was just afraid to break the rail and didn't tighten it enough. Is that right? Have you ever had someone break one of those ears off down below?