You probably won't be able to duplicate their load and might not want to try. I'd either buy a box and try them or load yours to your comfortable max. Or just load the MAXIE. They probably have a powder we can't get. I just started shooting some old 357s I had and am loading a couple test loads right now. Mostly only have lead from the old pistol days. I have to pick up some 158s and like to get some 170-180 soft nosed bullets hopefully this weekend. Don't want to push the old lead and only have jacketed hollow points in 110 and 125 on hand. Wondering how 110 or 125s will fly, Fast
I have a few left out of 500 cute little pointed 105 gr lead that I might load in some 38+P carts. for short range backyard critters
I don't know if the XTPs are the best choice for speed and deer. I had a little piece of paper that used to come with the XTPs, still might that showed the low and high vel. that they recommend. Think that was for people hunting though. Not sure how well they'd hold up. I had that paper, I never throw anything away, probably why I can't find it
I think the Speer SP @ 1800 should be a good load. Distance probably matters the most.
Added: I knew I put it where I could find it
I don't know if they still put the paper in with the XTPs, they did when they first came out. It says vels. for max Pen. & Exp.
38-158 HP/XTP 700-1400 fps
38-158 FP XTP 1175-1800+ fps
I've never found the FP XTPs yet but I think you can order them. I WILL