I used the stainless barrel and did not like it. Heating fast and groups started looking like shotgun pattern after the first couple of rounds. Heard that the stainless is much harder to harden than regular steel but I am no expert. Got an FN M4 and its very reliable, accurate and does not heat...
I would use a remote controlled aiming device on these...as the aircraft guided missiles are much more accurate than they used to be. A stationary target like that will be FUBAR on the first engagement from farther that a 50 can ring a bell with any precise effect.