The bullets are the same diameter.
My ported S&W 442:
Winchester Silvertip 110 gr. 821 fps = 165# KE
Winchester PDX +P 130 gr. @ 848 fps = 207# KE
Ruger LCP:
Hydra Shok 90 gr. @ 878 fps = 154# KE
IMO: non +p 38 VS 380 the difference isn't much
If you load +p in the 38 the power gap is more
My ported S&W 442:
Winchester Silvertip 110 gr. 821 fps = 165# KE
Winchester PDX +P 130 gr. @ 848 fps = 207# KE
Ruger LCP:
Hydra Shok 90 gr. @ 878 fps = 154# KE
IMO: non +p 38 VS 380 the difference isn't much
If you load +p in the 38 the power gap is more