If you want a 16, I'd shop for an upper with a 16 or just assemble from scratch. The 18 is a good length too though. As for the specific question, if both barrels take the same diameter gas block, and both are mid length, you would have good odds. As long as one of them doesn't have a funky length on the gas tube dimension. I have not reviewed the links to verify the data of each, but with that ammo you should be able to research the two a little.