Does anyone know if the Colt side sling swivel will fit the Bushy heavy bbl? How about RRA's swivel? Correct me if I am wrong, but isn't the M4 bbl 0.750" under the FSB? Are these sling mounts the same as the Bushmaster sold double sided adapter?

Also, do these swivel mounts clamp down tighly once you get the pins inserted or do they move around? Any advantages/disadvantages to this system? Do they put too much stress on the bbl and adversely effect accuracy?

I have one of the military issue side sling swivel adapters (with the gubment acquisition # on it) and I don't like it.  It doesn't fit tight on the Bushmaster or RRA barrels I had it on (which ARE .750" ) they do allow for some movement, but they're tight enough that they'll wear the finish off the barrel over time.

I will be sticking with the GG&G or KAC swivel products exclusively from now on.  If I didn't have a DD forend, I'd use the GG&G QD front sling thing to go with my Rear one.  As it is, I use the KAC QD for rails.  MUCH better product, although it's another $10 more.  No rattle, no finish wear, no worries, and QD to boot.

Onslaugt: good info, thanks.

I have one on my NIB colt m4 HB, BM m4, BM heavy fluted, fits the same on all/

Thanks for the info, guys.
Just ordered RRA version from Adco.

Thanks again, Steve!