On the other hand, add a single point sling, and might make a good RV gun or such, something where tight manuevering is the norm, and can't use/afford an SBR, but still want the punch of a rifle round. Not to mention, just a fun range toy, too. Can't add a forward grip without ATFE involvement, unfortuntely, that would help a lot.
That had to have been a custom build.