.30 TSS MODS

So, I’m going to build a TSS, and want to drop a 12″ .30 barrel into it. Since it’s a new version (fuck you AF… just. Fuck You), I would need the endcap/baffles, bushings and breech opened up to fit the barrel… problem is: since the breech is now larger, to fit the barrel, how do I seal against the tophat?? Who would be willing to do these mods for me somewhat cheap? I’ll pay shipping both ways…