Re: V-Tac TRX rails?
it is possible, i have one of the 13" version. its has a medium contour barrel in it. its possible and i have done it, but its pretty difficult to do especially if you have large hands. when i did it, i place a pinky in the hole directly under the hole i would like to place the rails on and then let the piece that secures the rails from within the tube slide into position in front of my pinky which acts as a stop. here's where its somewhat tricky, i then place the rail and screw under the securing piece with the supplied hex wrench. now you turn the screw and hope that it catches the securing piece's hole.
now i pretty much just take the whole tube off to place a rail on. ive read how some of the earlier tubes had problems where taking them off and installing them the second time would ruin the threads that lock the tube on, but ive done it a few times already and the threads on the tube seems fine.