[RAT76]

I'd recommend federal premium law enforcement 165 grain HST 40 S&W.

FWIW, The sweet spot for my P40 conversion was Fed 135 gr JHPs. 180 gr beat up both me & the gun. The 135s actually felt better than 115 gr 9mm. Somewhat more of a push than a slap.

Honking big hole in the end as well as much easier on an out of production gun.