I hunt with "tactical" SBRs. I've taken deer with them. One is a 6.5" barrel .300 AAC AR15, and I took a small buck with a subsonic load at short range in the woods. The other is a 10.5" barrel .458 SOCOM AR15. I used a supersonic 325 gr Hornady FTX a few years back to take a buck at close range. This year, I used a subsonic 500 gr Hornady RN Interlock through a Thompson Machine QMF-CQ .45 suppressor to take a buck at short range. The main reason to use these rifles is that they are very lightweight to carry in thick woods. They're a backup to my Remington 700, which I set up for longer shots in open fields.
The reason I mention that is just to say that an SBR of any sort is a great woods gun. I don't have any experience with a Thompson Contender. However, one of the leading court cases on SBRs and the "once a rifle always a rifle" (no longer true) issue is related to a Thompson Contender kit that was being sold. Thompson supplied a long and short barrel, a frame, and a buttstock. They included warnings to only assemble as either a pistol or legal length rifle, but the ATF said it was constructively an SBR, since it could be assembled as a short-barreled rifle. Thompson won that case--the United States Supreme Court sided with them that the kit, as sold, wasn't an SBR.
In honor of that case, and in light of the fact that SBRs make great woods guns for deer hunting, I say go for it!
Aaron
