SPEER doesn’t recommend ANY jacketed bullet over 125gr for .38spl or +P.
They more recently came out with a 135gr Short Barrel Gold Dot HP bullet (plated bullet with punched hp). But No JHP or JSP data.
The XTP is a slightly different animal in that Hornady claims it will expand at 700fps. IMHO, MAYBE... The 158 FP-XTP 1,150fps-1,800.
I suggest if planning to load self defense loads in .38spl with an eye to getting expansion, use a 158gr lead SWC-HP. They are proven to work.
I’ve got the remnant of 2,000 Remington 158gr JSP’s I bought in ‘03 for about $5/100. They’ve been superlative in heavy .357mag and full velocity .35Rem (2,500fps!) 17.8gr of Hodgdons Lil’Gun will give 2,100fps from a M94 Winchester 20” .357mag. (It’ll eat out the throat/forcing cone of a revolver however). That’s where those 158gr Speers would excell!
Though I recommend the 180gr XTP at starting levels if interested in shooting edible game (smallish pigs, deer). -.35Rem).