I've got a 20-ga fully rifled barrel for a TCR-87 and was looking into loading some 300-grain .45-caliber SST's into custom turned brass cases. I bought some Ballistic Products sabots and found that I could not force the sabots with bullets into the cases. The neck areas of the cases would have to have the thickness reduced. I was planning on using 5744 and hoping I could get a velocity of about 2200 fps with OK pressure and good accuracy. There is a lot of room for powder in those cases. Also the barrels outside dimensions are the same as the 10-ga barrells for that gun so it would stand well over 10,000 psi. Would the H&R slug guns be similarly strong? If so, it may be possible to get slug loads good for 250-yards for a fairly low cost.