Have had a little search around but have not actually found anything that answers my question so here goes.
I have a slot for a .243 sound moderator, am I only allowed to buy a 243 mod or am I allowed to buy any mod as long as it is more than 243 as it seems there are a lot of people using 30cal mods on 243's.
I was looking at the ASE Jet Z Compact and on their website it says it is suitable from 243-308 so when they are proofed are they proofed up to the maximum calibre.
sorry if this is a silly question or a bit hard to understand , I would have asked in my local gun shop but not planning on going in anytime soon. Many thanks Pete.