when i search and look at suppressors i see like 5.56 then it jumps to 7.62mm, if you have a 7mm rifle do you get a 7.62 suppressors and then make it fit?
YUP, a 7.62 sized can would be appropriate for a 7mm.
One can and many do shot 5.56 in 7.62 cans, maybe not as effective as can made specificlly for that caliber but it still works well.
I doubt you will find a non-custom made for 7mm.
In closure ,think of the caliber speciffied on the can as "will fit up to #.##mm" .
Also, make sure your can is rated for whatever 7mm cartridge you are using. For example, if a cartridge is rated for .308, it would likely do fine with a .284, but I might be nervous about putting 7mm Ultramag through it.
This discusses a 300 winny through a 308 can. Hope it helps.
BTW, that's assuming you are shooting full bore loads. If you are shooting subsonic ammo through them it's all pretty much good. A subsonic 338 LM round will not over pressure a 308 can (you'll just ruin the thing by putting a 33 caliber bullet through a 30 caliber hole)