I am looking to get an A3 stock for a Z5 RS, and like the looks of the original style A3 stocks, but in reading up on the differences, I read that the A3-F stock is an improvement in comfort over the older style, and made it sound as if the rails or arms are contoured differently... Has anyone compared the newer and older styles? Are there any difference other than the butt and  the buffer?

I like the look of the A3 stock, but the F style is a bit longer and yeah probably a bit more comfortable. I'm rocking the classic old school A3 and like it a lot though. If you're a lefty I'd go F stock, there's ambi sling mounts. Some F stocks are cut out for the bolt catch on the 40S&W/10mm Mp5's. 

I prefer the A3 stock to the F version because the F stock is too long in my opinion. There is a version of the F stock with multiple positions that I would like to get eventually but I can't justify the $500 price tag since my regular A3 is doing fine now. I generally tend to prefer shorter stocks though YMMV.

The F stock has two things going for it, it has a longer LOP than the older A3 and when closed it sticks out further allowing you more "wrist room" than the older A3 has. A gun with an F stock is much easier to handle and shoot with the stock closed than a gun with an A3 stock. Is it more "comfortable"? That is a matter of opinion... the buttplate is a different contour than an A3 but they both have the sliding rails that your face rests on, and a lot of folks dislike the cheek to rail cheekweld.

On the flipside the older A3 closes up smaller (sometimes that extra inch and a half or so can make a difference when storing or transporting) and it's buttplate has that older aggressive checkered texture buttpad that really grips your shirt or jacket (unlike the smooth buttpad of the F).

I myself prefer the classic A3... I've owned F stocks before and I just don't like how much they stick out when collapsed, and the longer LOP feels weird to me. But in truth my A3 stocks spend more time off the guns and in the parts box than they do in use. HK A3 stocks are for show, A2 fixed stocks are for go.

I like the A3 F stock, and I've tried different A3 stocks that have different rails. Some are curved and comfortable, some are thin and sharp. I'm not sure what the difference in talks corresponds to, but if it's F vs. non-F, I'd get the F just for the curved rails.

If you're serious about shooting it and compactness isn't an issue, get an A2 stock.

If both are an issue, get a B&T stock. There's stocks for every preference...

I really like the A3 stock on a full-size, the A2 stock on an SD, and the Choate non-adjustable on a K. The B&Ts are easily the best stock with regards to weight and comfort (and rock-solid lockup, unlike the A3 and Choate), but they don't have the purist look, feel, and idiosyncrasies of the original stocks.

I now have B&Ts, an A2, an A3, and a Choate. I've decided just to keep all of them and change it up as I feel like it, but I plan on using the A3 exclusively on a full-size...once I buy a full-size.

I would go with a B&T as well. The A3 looks cool, but it's definitely the last one I would choose having tried A2, A3 and B&T. They just came out with an adjustable version last year. Definitely not "purist" but way better than the A2/A3.



http://www.thefirearmblog.com/blog/2016/11/22/bt-4-position-folding/

From what I understand, one big reason for the extension on the "F" stock is for comfort when shooting with the stock collapsed. The older A3 slams the wrist if the gun is fired in this manner. If you plan on doing some John Woo style dual-wield shooting, then the F stock is the better one.

I own an A3 and two A2s and for my uses, the old A3 is the better stock in almost every way. Despite what people will tell you, they are in no way uncomfortable to shoot, and that goes for both 9mm and 5.56 roller locked guns. On the .308s, they can begin to get annoying, but unless you're the cozy type who demands the soft cheek weld of the A2, they are excellent on the MP5. I've had new shooters use them all day long and never complain once. I also prefer the LOP of the A3 over the A2, but I shoot my MP5 in the long-taught squared up subgun stance.

The B&T folders are nice, lightweight and comfortable, but to me the UMP look is completely out of place on a 9mm. They look good when combined with a modern, modular handguard like the DT, but otherwise they look like new Ferarri wheels on an old 'Vette stingray. There's also the added width that you have to contend with when the stock is folded, which means you have to take that into consideration for storage, carrying cases, etc.