Quoted:
Thanks hahrk-9 for replying intelligently, you understand my topic.
Oh by the way, the ACE installation instructions for installing the ACE Pistol Kit states, "Note: It may be unlawful to be in possession of an ACE AR-UL butt stock when an ARP recoil system is installed on your AR pistol." That warning is because the buffer tube supplied with the ARP is the same end threaded tube that is supplied with the AR-UL. It would be nice to have some sort of end cap that could be bolted on to reduce the possiblity of questions by LEOs.
As long as you don't own that stock, or if you do, have other rifles that the stock would fit, then there is no problem. The only possible problem is if you own the stock that fits the pistol tube, but do not own a rifle that the stock would also fit. Then one could make an argument against you because the ONLY way it could be assembled is into an illegal SBR. If you don't own the stock, no worries.
I run the ACE kit (actually, when I got my two kits it was before ACE made the kit and they put it together for me sans stock (yes it was in September 2004) and it has run perfectly on a 7.5 and 10.5 inch 5.56, an 11.5 inch 6.8, and a 12.5 inch .458.
Now, for kicks and giggles and as a sling attachment point, I drilled and tapped the buffer tube hole to accommodate the YHM rotating sling swivel stud. I think is 5/16 x 24 but don't hold me to that. It makes for a very convenient single point sling attachment point plus, I suppose you could argue, since the hole is drilled out then the stock that does fit the tube would no longer attach properly with the standard stock screw.
YHM-9469