Lancer Custom Ammo will make reduced power .45ACP that is reduced power factor. We tested the ammo in a number of .45 including all of the Glock models, the HK fullsize, Sig 220, Sig 220ST, Sig GSR, and a Springfield. The slide cycled fine in all of the pistols.
I have not checked his website - last I checked he still did not list the .45 comptition ammo. But I have shot it and in fact I had another 500 rounds delivered on Friday. If it is not on the web, then just call and ask for Mike. He's the owner and he'll take care of you.
The stuff is soft! Lancer is a big outfit - supplies many police departments for practice and competition ammo. Their ammo is sold in many retailers and by MidwayUSA.
Give it a try - you will not be sorry.