18in with 55 Grain will it be peak?

Hey everyone, we all know the (true) meme of 20in making 55 ball into duty ammo, but can the same bed said with an 18in? If Im not mistaken its a 50-100fps loss. Would 18in still be able to do what 20in can do or am I just better off with a 20in. I have different barrel sizes anyway but I was just curious would 18 achieve the same results.