I was on TheFirearmBlog website and there was a video about BOE suppressors.  One of the statements made was BOE was working w/ the ATF to allow consumers to buy a silencer AND additional mono-cores for different calibers.   Unless there is a secret out there I don't know about, I was under the impression that additional parts (baffles for example) are not allowed to be possessed.  How are they accomplishing this?

That's my understanding too, I would think the separate Monocores would be treated as suppressors themselves with additional tax stamps.

so I guess that would be why they are working with the ATF on the issue.

Maybe it's like the modular suppressors where you can take parts on and off.

OK, here's my great idea for sale,  I'll give VaFish 10% of the Million Dollars that I am charging for the use of this super, duper, innovative, cost effective, ultra quiet silencer.

Produce a modular silencer with (4), full length sections, yes, it will be about 24 to 32 inches long.  The first module is for 8.6, second for 308, third for 9mm, 4th for 556 (or whatever, you get the idea).  Effectively what you have is a 4 section, modular, AR silencer (4 endcaps please).

Pick you gun, choose your module, add endcap and mount and Bob's your Uncle!  Sure it's going to cost 2x to 3x what a normal can would, but you're getting 4 cans!  $1 Million Dollars please.