I have the 338 thunderbeast ultra for my Lapua. I thread it over the break. I'm very pleased with it.
I also have a thunderbeast 6.5 ultra 7. The 338 break threads are larger than the 30 cal thunderbeast threads so you will need the 338 break for any rifle you want to put it on.
For example I have a 30 cal thunderbeast break on my 6mm and I can screw my 6.5 untra 7 on it but would need to exchange the break to a 338 if I want to put the 338 thunderbeast on my 6mm.
Another thing you need to consider is the length your gun will be after adding suppressor. 31" barrel plus about 9" for suppressor will make your barrel 40". A 40" barrel is not really practical for some hunting situations.
I also have a thunderbeast 6.5 ultra 7. The 338 break threads are larger than the 30 cal thunderbeast threads so you will need the 338 break for any rifle you want to put it on.
For example I have a 30 cal thunderbeast break on my 6mm and I can screw my 6.5 untra 7 on it but would need to exchange the break to a 338 if I want to put the 338 thunderbeast on my 6mm.
Another thing you need to consider is the length your gun will be after adding suppressor. 31" barrel plus about 9" for suppressor will make your barrel 40". A 40" barrel is not really practical for some hunting situations.