I’ve got a G45 and a G19x, both fitted with PMM 2 ports and Acros. Both had issues running anything less than 124+p with the factory recoil spring, with failures to feed due to the slide not going fully to the rear. This manifested as nose-up feedway jams where the feed ledge (bottom of breech face) was engaging in the rim instead of behind it. 15lb recoil springs fixed both and will run very very reliably with everything I’ve put through them. I think the lightest loadings I’ve run were either PMC 115gr or a few rounds of unknown weight syntech and probably 2k rds of Wolf. With the OEM spring I’ve run a few (maybe 5-6) rounds of 9major and it surprisingly did not feel like it was beating the gun up too badly.