They "AR" The Problem

Not in this sense of course.....

Absolutely, in this sense of it,..... that of an infinitely flexible system where the parts are different, yet interchangeable as well as just complex enough so that it's sort of challenging. A couple of months ago, I finished my AR as an "M4" or "carbine" (16" barrel) version. What that means is that, as long as it has an upper receiver with a barrel of 16" or longer attached, we're in good shape, legally speaking. 

....but let that barrel drop under 16", just one hair......, that completely changes the definition of what it is and you may have some issues. So, lets back up to where we started: I built a carbine. What makes it a "carbine" is that the barrel is less than 18" and that the gas port is either carbine length or "mid-length" as mine is known as. 

In the image above, you have the actual definitions. The original AR15/M16 as designed by Gene Stoner while at Armalite/Fairchild, had a "rifle" length gas port, meaning 12" forward of the chamber. And the .223/5.56 cartridge was designed to function within those parameters to have the gun's action work properly. Recoil-wise, this was a very mild feeling gun. Then the shorter versions came along which were designed with shorter gas port system and they weren't nearly as smooth in function or feel. For simplicity sake, we'll make the generalization that the shorter systems tend to be more difficult to get running properly. In the current generation of almost across-the-board carbine/16" length barrels, that's become the norm, so the mid-length (what I have) are generally perceived as being smoother and more reliable guns. 

However, the rage these days, is the pistol. This is mostly due to people skirting a federal mandate that arbitrarilly uses that 16" length as a "continental divide" of guns. So, if you want a gun to have less than a 16" barrel, you have to file papers to have a "Short Barrel Rifle", pay a $200 tax to get a stamp, and wait..... somewhere between 6 months to a year to legally possess such a thing (or even the parts to build such a thing)! That is unless you buy/build a "pistol", which is essentially the same thing, but without a "stock"! You can have a pistol brace, and even ocassionally shoulder said brace, but it can't be a stock! So, now, these are the hottest thing in the world of ARs! All the convenience of the SBR without the complexity and/or costs.

My intention is to take a 10" barrel and make a pistol upper for myself. These tend to be not nearly as difficult to get running properly as the shorter pistols, as they often have the 7" "carbine" gas port. Then last night, I was seduced by a Christmas sale!

A sales notice arrived in an email advertising that Combat Armory had a fully assembled 7.5" pistol upper for $110! It was too much to resist. Now, one of these is on it's way to my house. Granted, it'll spend the vast majority of it's life as a 22LR surrogate where my CMMG conversion bolt will live, but, it still is a fully functioning .223/5.56. When it arrives, it'll go right on top of my already finished Aero Precision pistol lower and will be ready to spread some holiday cheer.

So yeah, the whole thing is rapidly headed in this direction.... and there-in lies the problem!