OK, this isn’t a shoot off or anything like that. I just heard somebody state that a Glock 43 with a magazine extension is the same as having a Glock 19 when it comes to concealability.
Yeah… no.
I happen to have a Glock 43 with a +3 mag extension from Taran Tactical, and a Glock 19 with a stock magazine, we can easily compare the two guns side by side.
Concealing a carry gun involves several factors.
- Height is the distance from the top of the slide to the bottom of the magazine.
- Length is the distance from the end plate of the slide to the muzzle, and will also include the rear of the grip if it extends past the end plate.
- Weight – well, all of us understand gravity and its impact on everything.
- Capacity of each gun will differ, and capacity will impact concealment by adding weight and size. It is, absolutely, a trade off.
- Capability of each gun differs, but only very slightly, and it really doesn’t impact concealment.
Let’s look at each of these factors.
Height – With the extended +3 mag, which is pretty much one of the larger 
ones out there, the measurements are pretty interesting. The Glock 43 from top of the slide to bottom of the extended mag is just under 5 1/8”, not including the sights. The Glock 19 is just under 4 7/8”, not including the sights. So, with the super big extended mag the Glock 43 is about 1/4” taller. Pretty negligible.
Length – Obviously, the Glock 43 will have no change from stock with the 
extended magazine. The length of the Glock 43 is a touch over 6 1/4″. The Glock 19 is a bit over 7 1/3”. So, well over an inch in length difference. It is pretty clear that the Glock 43 is much smaller.
Weight – I don’t have a scale nearby to measure the Glock 43 with the extended mag, but I am certain that it is safe to say that it is less than the Glock 19. I doubt anyone would argue that, but if they leave a response, I will make sure I verify. The local grocery store is starting to get used to me weight hand guns by using the fruit and vegetable scales.
Capacity – There is a big difference here. The Glock 43, with the extended +3 mag, puts it at 9+1. The Glock 19 is 15+1. Obviously, concealability is very important, so we see single stack guns like Glock 43 holding fewer rounds than double stack guns like the Glock 19.
Capability – There is a difference in sight radius (thus, accuracy at distance) and bullet velocity. The Glock 43 is on the short end of each of those measures. However, as a defensive gun used in close quarters, those measures don’t mean anything at all.
Summary
The difference in concealability is really measured by the eye of the beholder.
Which of the two guns will print more and which impacts the lengths that we have to go to as a concealed carrier? I can speak from experience, I have to go with my extra baggy jeans to carry my Glock 19, but I really don’t have to change my clothing style to carry the Glock 43. Yes, I have to give up capacity, but that is really all I lose. So, maybe I should carry one more mag when carrying the Glock 43. 