Yes you can make a multi caliber can. They're likely not going to approve "MULTI" just like on a form 1 SBR they no longer approve "MULTI" for the caliber even if that's what the receiver is marked. They will approve whatever is the largest dia you want it to be for which will also naturally fit any dia under that. The Silencerco Hybrid 46 is rated diameter wise up to .460". I have one and have used it on 17HMR on up to 450BM. My two Form 1 cans are a .22" for quiet plinking and a .38" that will take at least up to my 375Win or 375FUW. If I was smarter at the time I'd of gone with .46" for the .38" can and never bought a Hybrid (even though I really like it).