Ok, I have a DPMS AP4 in .308

Having 1 rail for a vertical grip seems attractive.

Since the FF tube is Alum, and some rails available are Alum, is there an issue with simply drilling and tapping 2 holes in the FF Tube?

Sure would be cheaper and simpler than buying a new quadrail for 1 rail.

Has anybdy done this?

thanks.

I'd have it done professionally, it seems just too easy to screw up and do wrong.

But otherwise it seems like a fine idea, as long as you can find a peice of rail that fits flush.

I did this with the round rail on my AR-15 pistol which had a DPMS forend.  I got 3 rails and Accra Glassed them in position on the rail.  This allowed for time to get everything aligned perfectly.  Of course, let it cure over night.  Next day, leaving the rails in place, I used the holes in the rail to act as a guide for the clearance bit.  Once dimpled I used the tap bit to complete the hole and then tapped them out.  Not a big deal at all.  If you want the rails removeable, put some heat on the handguard and the bond will break and the rails will come off.  Then screw them on and Lock-Tite them in place.  Worked fine until I retired the handguard for a locking YHM 4 rail just last week.

I have done a few. but i would drill the handguard and back it with a nut. rather than tapping it. I have tapped them as will but aluminum threads are fragile. If you going to leave in no for good that may not  be a problem but you don't want your rail coming loose. hope this helps

Craig

thanks guys