DGHQ, I have reloaded steel for both 12 and 10 ga. for a number of years.I do this in order to keep the pressures at approx. 8000 psi.so they can be used in several of my older doubles,some with damascus barrels.I load 1 oz. loads in 2 3/4" 12ga. and 1 3/8 oz. loads in 3 1/2"10 ga. The velocities are in the 1400 ft/sec. range. The max. size I load in 12 ga. are #2's and in the 10's #1's. I have shot several hundred rounds through a Scott 12 ga.SLE circa 1890 with damascus barrels and 15 and 20 thou of choke. These loads are deadly to 40 yds and there has been no scoring of barrels or any visible or measurable bulging of choke. I have shot a similar number of rounds through a heavy Greener single 10 with a 38 1/2" barrel and 20 thou of choke and observe the same result.I have also observed the demise of several dozen snow geese and a few Canadas at ranges to 50 plus yds. I would not shoot factory loads through these guns because of the excessive pressure,nor use steel in guns with more than 20 thou of choke,nor use the larger sizes of steel,ie. BB and up.plus I would recommend long forcing cones when shooting steel. BTW, the Scott SLE is 2 3/4" recent nitro re-proof and the Greener has a massive action and serious barrel wall etc.I'm not suggesting you do what I do, just relating my experiences in this area.which I believe is the info you were inquiring about.
