For a 45acp your suppressor will need to be able to have a piston installed to reliably cycle a semi automatic. Assuming it's a handgun and not a fixed barrel 45 carbine. A great candidate for this is the Silencerco Hybrid. I have one that I've used on .223-45 acp and a lot in between. It's a 46 cal can and can be used on just about everything including 45-70. It is definitely a RIFLE can that works on handguns too, but is bulky for handgun. Ideally a good 30 cal can and a dedicated 45cal pistol can would be better suited but for a do it all, the hybrid is tough to beat. I can go from my short barrel 5.56 to my 6.5 creed to my 1911 in a matter of minutes.