The Beretta Nano has a height slightly over 4" like the Kahr CM9, which I also own. It is barely noticeable, even when you are carrying it. I will say that I feel like Beretta could have made the magazine fit flush with the grip like the PX4 pistols have. It would make just enough difference to advance it into the realm of being one of the smallest pocket pistols, I think.
You notice that it has no slide stop, which allows no criticism for added thickness. The gun is blocky in general, but with very well rounded lines and sexy contours that try to give it a mini-PX4 appearance. I think the Nano could definitely have been thinner. But we must remember that the pistol was built to facilitate the .40 caliber cartridge, which would naturally demand that the slide be built a little stronger, or thicker in this case.
As I mentioned before, the pistol is missing a slide stop which leaves the profile nice and slim. But I think there was going to be one initially. If you look at the left side of the frame, you will notice a silohette where you could have a cutout for a slide stop to be installed, but the pivot point is taken up by the disassembly pin. Personally, I think a very low profile one would work just fine to calm the nerves of people worried about malfunction corrections. Something with a profile like the stealth decockers for the PX4 pistol may be a good example of what could work well. Place that right behind the cutout silohette and they would be golden and forgiven for most transgressions I think.
The only control that the pistol has is a reversible mag release that heavily resembles the mag release of the PX4 pistols. This button is a bit stiff out of the box and needs some work to get the tension down to a reasonable level for reliable ejection. But this isn't really a deal breaker, just a note to make about this control.
The grip on the Nano is definitely a unique one. The pistol feels very weird in your hand at first, even though it points naturally. I will note that you better not cant your wrist forward or you will suffer with low shots. This grip allows you to point the pistol very naturally. Believe it or not, a pistol with a high slide is actually going to lend itself to being shot more naturally than a pistol with a low slide. Low profile slides and low bore axis' on a pistol will require a more unnatural lifting of your shooting hand(s) in order to look down the sights. Also, I never notice that low bore axis helps in recoil, no matter the caliber I was using. It is a lame duck excuse that is about as irrelevent as dismissal of a pistol for the trigger reset. But we will get to that.
The texturing pattern of the Nano is almost a direct copy of the pattern found on the PX4 pistols. They are nice and aggressive, but you don't see it until your hands are sweaty. By then you start to see the genious of the texturing pattern and why the grip is shaped the way it is. It is designed to keep your hand high on the grip under all conditions by way of grip pattern and the effective clustered pyramids used as texturing.
The sights on the Beretta Nano are also unique. They are one of the lowest profile set of stock sights I have ever come across. They sit so low on the slide that you could almost miss the three dot sight picture for glare. The main objective is to prevent snagging and being a nuisance, which I can respect.
The sights are also designs so that you can chang them out and adjust them yourself with a small hex wrench. This is a nice feature, but I would say that it is a bit overkill for a pistol of this size. But options are money in the gun market, so you can't really fault them too much for that.
The trigger on the Beretta Nano is of the standard DAO category, commonly found on pocket pistols. This doesn't require a manual safety, and really isn't hard to get used to. Many people have complained about the trigger weight on the Nano, but I happen to have a 5.5lb trigger pull. Many complain about how the trigger is heavier than they would like it to be. Usually I find that these people have not shot their pistol more than 100 rounds and already judge it without working out the friction points. Through proper lubrication and shooting my pistol over 2500 times, I find the Nano trigger to be one of the best DAO triggers out there.
The Beretta Nano has an amazing way of recoiling. For a single stack pocket pistol, I swear that this pistol has less recoil than my M&P Shield. I shot the two side by side during an early round count and sure enough, the Nano had less recoil and muzzle jump. AMAZING!
Beretta credits the low recoil on their recoil spring system, which they call a "variable compression" spring. In laymans terms, the tension increases as the spring compresses. But that is just a fancy way of saying that they use a dual recoil spring. The pistol is said to have been originally designed around the .40 caliber, which explains the heavy spring. But this spring system is what a lot of manufacturers are finding to be a superior way to control the recoil on a variety of different loads. Not to mention that it also efficiently handles the recoil of the slide, moreso than flat wire springs apparently. But who really knows, right?
It is no secret that the Nano has been plagued with a reputation for having issues with ammo that is in the 115 grain category, and even all loads in general. One guy claimed to have constant issues with his Nano where 15% of all the ammo he fired had a failure of some kind or another. Now this is an interesting thing, because almost every review I have seen, save a few, has said something about having issues one way or another.
I have only had two issues in the 2500 rounds I have shot through the Nano, and it was caused by aluminum cased ammo from federal. Keep in mind that I also used mostly 115 grain ammo to get to this round count. I will say that the pistol seemed to have smoother recoil with 124 grain NATO ammo. If you do have issues with ammo, I would recommend keeping track of it and start shooting it faster and harder with hot ammo. This should help break in the spring a bit. But if you still have issues, you should contact Beretta. They have great customer service and will take care of you. In the few instances that I have had to send my guns back, Beretta has always been very quick, detailed, and professional in getting my gun back to me and getting me parts.