DF, listen to MSH, he is well versed in the different platforms...well versed, ok extremely well versed....ok god like...LOL
If I were you, take a deep breath and just make some calls.....
Check JP, PRI, and the other one posted....one question to boot, did you by change call ArmaLite and ask them if theirs will fit other rifles....it may, but don't quote me on that....and one last thing...On the links I posted,,,,,the one for DPMS has the PRI and JP adjustable gas blocks....so that in it self should tell you that they will work....OH I am going to catch crap for this from MSH.....lol
On the KAC and the SUPER SASS they both have the
"gas buster" charging handle as well, to divert the excess gas out the side of the receiver as far as the excess blow-back and to help regulate the pressure, now the S-SASS has the adjustable gas block where as the M-110 SASS (KAC) does not....so it can go either way....MSH will probably be on me for this one....LOL
I think the reason they are telling you that it can't be that way, I may be wrong on this- unless there is a mechanical reason, which I doubt, is that these days certain companies do not want to promote the use of a can ability....I think you can understand that one.....hope this is some help..
BMS