Oh, I have one of those, and a full sized AR. I am more talking about either being stuck four miles from home, or just to have in the truck, in case.
If it is a bug out situation, I have that covered (probably more than I could ever use—someone picking over my stupid corpse would be happy!)
You may want to consider a conversion kit for a 45 cal. that does not require a stamp. See the link.
http://www.outdoorhub.com/pr/2014/03/27/kpos-g2p-pathfinder-pdw-conversion-kit/