So I have a charging handle with loose roll pins. they can be easily pushed out with a punch.

What would you recommend to fix them? would Loctite work? need to find bigger pins? can I enlarge the pins to be a tighter fit?

Lay the pin on the benchtop, seam side up.

Place a sharp chisel into the seam.

Give it a tap.

Not too much. Better to do too little and have to tap it again, than to make it too big in one fell swoop.

That should make the pin last a while longer.

If it gets loose again soon, buy replacement pins.

New roll pin-cheap might be large enough to stay in place.

Drop of loc-tite, you probably already have that at home. Would it impede any pivoting movement?

Enlarge the pin-do you have a steel punch with a slightly larger outer diameter?

I've used Selador's method with good results. Be careful with the chisel though, one slip and the pin can vanish into hyperspace..

If it's only a little loose, not falling out loose, you can try a very small drop of Loctite 290.
290 will actually wick into the pin/housing joint and keep it from losening up in most cases. It can still be removed with the punch.

I tried the enlarge it try, seemed tight to install and normal pressure didn't push it through. so it might work for a spare

IIRC, you can get a plastic tub of various roll pins at Harbor Freight. I would either enlarge the hole and replace with a larger pin, or expand the pin as described above.