I just finished putting La Rue FF's on my 16in BM. I also installed a LR low profile gas block. My question is when I put the block on, it did not sit over the two slots that are in place for the FSB pins on the barrell. I made sure it could go back no further , then installed the set screws. Sine I also installed an A3 flat top, I made a small line(inside under were the charging handle would be) on the A2. (were the gas tube came from.) When measured the tube(in the A3) is the same distance from the opening of the BCG to the gas tube as the line is from the opening of the BCG on the old recciver. Just wanted to know if its normal for the set screws not to line up with the FSB taper pin slots. Is there any way to check and see if the gas tube hole is properly alligned to the barrell? Took everything out of the BCG and pushed it with my fingers only, back and forth. I did not have any trouble moving it back and forth nor did it have any problem slidding up to the locking lug's.

Hi I have done several with Larue gas block's. Each Mfg. has a slightly diffent placement of the tapper pin holes. Just use a center punch to mark were the center of holes are. I will use a small drill bit. and just indent two small craters in barrel. Then locktight the Larue screws in place. Very secure. Just make sure your gas tube hole and the hole in the gas block allin up. Fine tiped pencel mark work's.