I appreciate the feed back on the use of a pistol vs SBR when practicing on the range, but as I said, there's never any hallelujahs of praise when the stock goes on and how much the accuracy has improved. It's more a defensive justification for the cost of the tax stamp, and until I see targets posted I'm not convinced. Further, we are talking ranges measured in feet, not yards, especially indoors. If the weapon was degraded from 2 to 4 MOA, that is still an opening up of the dispersion of a group from 1" at 50 meters to 2". At 15 feet I don't see any effective reduction, bullet placement by practice, and sight offset by the elevated sightline on the AR15 are going to be much more dominant than the extra fraction of an inch the bullet might deviate.
The fact that you keep talking merely of accuracy alone is telling. As to the mechanical accuracy, no it will not change at all. It comes down to how usable the gun is. Standing on a square range taking one's time one can do okay with an AR pistol. It will be easier to be consistent in mounting the gun, which affects accuracy with a real stock. However, accuracy of groups is not really the issue. Defensive shooting tends to occur in dramatically different circumstances than a stagnant square range. According to Ken Hackathorn it most often happens in low light, there are multiple bad guys, and everyone is moving. It also tends to happen quickly. The accuracy one is capable of achieving is important in that almost everyone suffers a degradation in low light and when he/she is moving, and when the target is moving. Add to that the effect of a two way range and a time is life situation. As big a factor as accuracy is time with an SBR vs an AR pistol. When talking about defensive shooting we cannot just talk about accuracy we also have to talk about time. This is why defensive drills have accuracy and time standards and often link them together. For example an El prez, you have a par time to make and (at least in the versions I have learned from some good trainers) you then add significant time penalties for putting rounds outside the A zone. Time and accuracy both matter in defensive shooting. Also for learning defensive shooting all these drills are done moving as well.
If you do not think that having a stock makes a world of difference over just a buffer tube, I would ask how much shooting you have done on a shot timer with one? Seriously have you ever used one against an SBR comparing performance with a shot timer? Take your AR pistol to a carbine course. Take it to a practical shooting competition. Or like I said before shoot an assortment of the standard drills with each say:
1. a bill drill
2. an el prez
3. a 1-5 drill
4. 2x2x2 drill
5. 9 hole drill
Then do the above moving and other movement drills such as:
1. Box drill
2. zig zag drill
3. horizontal and vertical figure 8s
Record times with a shot timer. Make sure you add time penalties for poor shots. That is to say if you pull a shot out of the A-zone it is a 1 sec penalty (C zone), if you make a hit in the D zone it is a 3 sec penalty, if you miss completely either consider it a fail or add a 5 second penalty.
Don't ask for pictures of targets on the internet. That isn't going to teach you a darn thing. Furthermore they are meaningless with out consideration for the conditions and time in which they were shot.
Since the advent of the SIG Brace, the number of AR pistol builds has increased a lot, and it can also be noted that the return time on SBR applications has dramatically reduced.
I would posit that has much more to do with the fact the ATF hired a number of additional full time examiners and has now allowed all examiners unlimited overtime.
f the combat shooter has one universal quality, it's a strict mindset that only accepts long proven and established doctrine.
Interesting, the trainers I have been exposed to take a very different approach. Rather than preach dogma they strive to develop what works in the real world. I do think with in some institutions you get inertia that prevents the quick adaption of better techniques and advancements.
The problem with the sig braces, at least for me is they are too dang short. The LOP is off and affects how well I can use that weapon. There are folks working around that. Its also just not a great stock.
Another notable issue with them IMHO is that the ATF could change their opinion of them tomorrow. There are instances of the ATF changing their opinion about what is legal and what is not. A couple examples include the parts count on S12 shotguns and whether SBRs are subject to 922r. If that occurs with the brace as an owner I'm stuck with a expensive crappy stock.
Another draw back, although not fatal is the fact that one cannot mount a VFG. Some people don't mount them anyways. However for positional shooting they can bee a big benefit if one knows how to make use of them.
Until the facts come out, we have opinion, and that is always laced with personal bias.
No offense but it seems you have opinion based on no experience and reading second hand accounts on the internet and furthermore they may or may not be accounts of things that are even pertinent to defensive shooting.
Same problem the AR based SBR's faced in the 90's when the HK MP5 was the dominant weapon, they aren't so much in evidence any more. There is the professional answer to "pistol caliber carbines," and the answer is "no thanks."
Short M4 style guns are taking over many roles traditionally filled by SMGs. PDWs have also taken a chunk of it. However, I would not yet talk about the MP5 like it is not out there at all though or has been completely replaced by other weapons. It is in decline but it is far from dead based on what I have seen. At a job I had only a few years ago I got to see what a lot of foreign dignitary protection guys were using. I saw a lot of MP5s. I saw a lot of MP5s in Europe in use by various police, I do know some of them have been replaced with MP7s. I also know of a number of SWAT units still using the MP5 or using it in conjunction with other options. Some of the insider chatter surround Sig developing the MPX is that there are a lot of MP5s coming to the end of their service life and HK is trying to push their end users to other products. However, those end users want a 9x19 sub gun for various reasons. Like I say the SMG, has definitely lost a lot of ground (I think I raised that point myself earlier in this thread) and is being subsumed, for good reason IMHO, but to be frank I think your comment overstates the situation a bit.
In sum, if you want to know how useful an AR pistol is versus an SBR (or heck even a 16" gun). Do yourself a favor and go out and shoot. Why sit on the internet and ask people to prove it to you. If you don't have the hardware, facilities, or knowledge base to do so just say. And if you are relegated to asking then at least ask for relevant matrices.
