Got a DPMS float tube, have some extra sling studs but wondering about proper way to install.

Are they self threading?  Could I drill a hole an JB weld it?

Before I install the stud, I will shoot the rifle for a few hundred rounds, then re-tighten the tube to make sure it's tight.  The last thing you want is to index the stud, then have the tube turn.

On placement, I use the bipod for location of the hole, drill the hole to tap for the threads, then back it up with a nut(with beveled washer) on the inside of the tube.  Just remember to use a press to prevent the hole from being canted when drilled.  Also, the use of loctite is a must to keep if from turning is you use the stud for a sling when the bipod is off the rifle.

Hope this helps.

What equipment is needed to tap the hole?

Quoted: On placement, I use the bipod for location of the hole, drill the hole to tap for the threads, then back it up with a nut(with beveled washer) on the inside of the tube.  Just remember to use a press to prevent the hole from being canted when drilled.  Also, the use of loctite is a must to keep if from turning is you use the stud for a sling when the bipod is off the rifle. Hope this helps.

Quoted:
What equipment is needed to tap the hole?

A tap the same thread as your stud.

Why bother tapping the hole in the thin aluminum tube at all? Just drill it out to clear the stud and use a nut and a cup or lock washer. If you have a three piece tube, you needn't worry about the index.