Gents:
The recoil issue is from the high velocities. If you throw the shot at moderate velocities, then , using m1v1=m2v2, solving for v2, and then subbing back into Ke = 1/2 Mv^2, you will not have any more recoil than if you shoot lead.
I have handled on 3 different occasions 870 barrels with deep parallel scores in them. Someone was either shooting rocks in them, or steel. Which one is anybody's guess, but I bet it was steel shot.
I have in my closet, as we speak, and as I type, a very nice Le Shootsgun Belgique, a J. Saive Armes, Liege, 3-1/2" 10 gauge mag. The gun bears the date code of a lower case Greek lamda, meaning proof date of 1958. It is meaty, massive, heavy, and modern.
The barrels are gently bulged at the choke, and the barrels exhibit faint parallel scoring for about 20 inches. I am going to have them polished by Orlen to remove the scoring ( I hope) and intend to reduce the bulges with some judicious peening , as I have in the past.
To the meat of the matter, though - the bulge and scoring came from somewhere. I would hazard the guess that it came from firing steel shot.
Maybe steel 7-1/2 's will work just fine in a damascus barrel. If Keith Kearcher uses steel in damascus he must feel at least somewhat comfortable with it. More power to him- he has the skills to fix the damage, if any should occur. I would question either the wisdom or ballistic efficiency of steel 2's and larger in a damascus gun.
I guess thats 'nuff said.
Regards
GKT