The 38 special case can go way overboard with higher fps and
still not show high pressures.

I tested full 38 loads in my "L" frame 686 357 magnum and
logged the fps . I then added more powder to three bullets.

A 158 XTP went from 832 to 979 fps. ( fast powder )
A 158 lead went from 909 to 1024 fps. ( med. fast )
A 110 XTP went from 1080 to 1305 fps. ( med powder )

These had pressure signs in the Magnum.............
I would hate to see what would happen if they ended up in even
a STEEL J frame with a mag frame, if someone let it happen.

I never load a 38 special more than a "Standard Pressure" loading
if the case does not have a +P stamp on it.

Too many standard 38's in my family ..... and any +P loads are well marked
and kept separated from the standard ammo.

Full loads are fun now and then but 98% of our shooting is with
target or standard loads, which lets us shoot more without hitting the asprin bottle.

Good shooting.