I have two projects I'd like to complete. First I'd like to build a 5.56 pistol utilizing a piston system along with a foldable KAC blade if that's possible? I've seen attachments that allow an ar stock to fold to the side. I'm not sure how an AR can cycle like that unless they use a special bolt as well. Secondly, I'd like to build a similar setup for a pistol caliber, that utilizes a Glock magazines - probably in 9mm, 40S&W, or 45acp. I live in VA so I'm not restricted beyond what the Fed's would allow less an SBR setup. That's why I want to use the KAC blade. Id like to know for certain, that by making the KAC blade foldable (if thats even possible) on a registered pistol lower would that still be legal to own without an SBR stamp. Any tips or suggestions on the build and parts needed would be very helpful also. I really like Seekins billeted uppers & lowers for the 5.56 pistol build, however I'm not as informed when it comes to knowing what pistol caliber AR upper & lower manufacturers are best. I've already read a few suggestions on which piston system works best for the 5.56 build, which would also end up as a host lower for a 300AAC upper from time to time. The trigger I'm looking at is the Tac Con, of course the FosTech Echo trigger is very interesting as well.

With the Law Tactical Folding Stock Adapter, firing more than one round from concealment with the stock folded is impossible, so other than an emergency shot, you’ll have to fold the stock back out to finish engaging a target..

I am guessing you are talking about the Shockwave blade? The one that KAK seels? KAC is short for Knights Armament Corperation. KAK industry is complete  different.  Now as far as a folding stock the Law Tactical Folder is about the best option for a folding stock, but due to the ARs design it can't be shot folded,  i guess you could shoot one shot, but then you would basically have a club. If you want to shoot a rifle with the stock folded your going to have to look at a different platform.

Thanks for the advice. After father research I came to that conclusion as well. A few options are out there based on an AR platform but with differing bolt/gas systems such as the Sig MCX and the RRA AR pistol. The later of which comes with a warning not to be used with a suppressor. With that information I'm strongly considering the Sig MCX or MPX. I do not have a suppressor as of yet but I'd like the option to do so in the future should full ds allow.