I suspect this might be a bit of a pipe dream but if you don't ask you don't know...
I see on some muzzle brakes that there is what looks like a nut (like a nut and bolt) without a thread, sat in the front of the brake.
If this nut weren't in there the hole at the end of the brake would obviously be far too big for the calibre of rifle it's attached too.
Is this nut interchangeable for different ones to match different calibres?
What I'm picturing is having a couple of the same rifle in different calibres which all have the same barrel, and a clamp on brake with changeable 'nuts' for each calibre, so you can use the same brake on a couple of different rifles.
Couldn't find anything after round on Google. Does such a thing exist?