I believe that the SP101 was designed as a concealable revolver, rather than a revolver for firing heavy loads. With the factory grip it can be hidden where most revolvers could not be. A practical cartridge for CCW with this gun is the .38+P. I carry the "FBI Load" (.38+P lead SWC hollowpoint) in both the SP101 and the Ruger LCR-357. Both of these revolvers can be rapid fired with .38+P, but I can't shoot the magnums fast.
For something like bear or hog defense (we're being overrun in TX with feral hogs, and they're dangerous), the SP101 can be carried with magnums. I like the Hogue rubber grips for the heavier loads. They aren't fun, though. For CCW, I favor the nylon Hogue grip. It doesn't grab clothes and print the way rubber can, but it is great for the recoil level of +P carry loads.
I see the small-frame .357s as heavy-duty .38s that can take a steady diet of +P ammo and can be used with magnums if that's needed. For the record, I haven't shot .357s out of the LCR-357 and I have no plans to do so. For shooting full-power .357 loads, I recommend a Ruger GP100 or S&W 686. The Ruger Blackhawk and Vaquero (especially the original Vaquero) are also great for .357. The most fun I've had shooting heavy .357 Mags was in a T/C Contender. Accurate, powerful, and fun.
All my best,
Dirty Bob