I want to mount a sling adapter to my M4LE, but the locking ring on the buffer tube was staked
at the factory. I have the lower in a mag well vice block, but I can't seem to budge the locking ring
with a wrench. I considered tapping the wrench with a hammer, but I'm afraid it will put too much
presure on the mag well and screw it up. So, what do I do?

Thanks

Try harder.

It should shear off that little piece of steel without damaging anything else.

WIZZO

I managed to get it loose. DAYUM, that was hard!

I had the same problem with my Bushmaster.  I used a hammer on the wrench to try to break it loose and ended up breaking the wrench tooth off.   I finally was able to lossen the nut with a hammer and punch.    It did  ruin the buffer tube by messing up a couple of treads on it.    Once the nut was loose I just backed it off and it came right off.  I was replaceing the tube anyway as it was not mil spec and would not work with my new Vltor stock.