Made a quick range trip this morning. The rifle still shot 357 mag and 38 Spec ammo as well as it ever did. Shot 3 different loads of 357 max: 125 gr Win JHP's, 180 grn XTP's, 200 gr FTX's all over a medium helping of H110 with a small rifle primer. The 125 grn load was sort of eratic, I only loaded them because I have a bunch and I figured if they shot OK they may do for coyotes. I'll just say that that won't be my go to load for yotes just yet. These grouped 4" at 50 yards and 8"+ at 100 yards. The 200 gr FTX's did well presenting a 1.5" group at 50 and 3.5" group at 100 this will probably make a decent big game load. The best load of all was the 180 gr XTP's. This load presented nearly clover leafs at 50 yards and 1.5" at 100 yards. Looks like this will make a good hunting load as well. I wanted to throw together a 158 gr XTP load as well but ran out of time.
Had a good time, it was a brief trip (under an hour) and I was shooting off a bipod as I didn't feel like dragging the sled along today. Quite impressed with the new chambering. Definitely a bit more stout of a report than the 357 mag but still not a lot of felt recoil.
Not sure how much hotter I want to go on my loading as the jury seems to still be out on the pressures that the SB1 can with stand. For now, I'll stay with loads that are south of the pressures that the 44 mag makes as it is factory chambered on the SB1 frame as well.
I'd recommend this re-chamber to anyone with the 357 mag handi.

Lazermule