If you look around Instagram very much you’ll assume that everybody who owns a Glock has put an aftermarket barrel in it. I’ve seen random posts in various places decrying the accuracy of the stock Glock barrel and how you “need to replace the barrel” as soon as you buy it. I have tested the accuracy of several stock Glocks as well as several aftermarket barrels, and my experiences are different than internet lore. I can’t claim that my experiences are comprehensive, but after trying out a lot of different things, I’ve come to several conclusions.
Firstly, the stock barrel in a Glock is pretty darn accurate. I’ve found the barrels in all the generations I’ve tried to be quite capable. I can’t say the same for other brands of guns, but this posting isn’t about that. What I have seen is that the stock Glock barrel in most Glocks is capable of 2”-3” groups at 25 yards, provided you use decent ammunition. In my experience that level of accuracy isn’t achievable by most shooters, so I will stand by the general observation that the gun is more accurate than 99% of the shooters owning them. I have found that the generation 5 barrels are slightly more accurate, although quantifying it really depends on the gun. My gen 5 Glock 19 was capable of hitting a 3x5 card at 50 yards (3 out of 5 shots) when I was checking the zero on the dot a few months ago.
So, with that in mind, there are really only three reasons that I can come up with to change out your barrel in a Glock:
You want a threaded barrel
You have a worn out stock barrel
You want something that looks cool
If you want a suppressor or a compensator on your pistol, you’ll want a threaded barrel. While you can find threaded stock Glock barrels, they aren’t easy to come by. What is much more likely is that you’ll pick up an aftermarket barrel. There are a lot of choices, especially if you want to go with a different finish, fluting, dimples, etc.
Perhaps you’ve worn out your stock barrel. If so, you may wish to either buy another stock barrel or an aftermarket barrel. I will say that it isn’t easy to wear out a barrel. It is doable, but I suspect that you’ll have to shoot somewhere between 40,000 and 60,000 rounds to do that, depending on your rate of fire and the ammunition used. For most shooters, a worn out barrel would be indistinguishable from a new one unless you’re shooting accurate ammo and looking at your groups. My Glock 34 barrel is a bit ragged, but it still shoots a 5-6” group at 25 yards. Based on what I’ve seen at the range, most people wouldn’t be able to tell the difference. That said, I finally replaced that barrel due to the loss of accuracy.
And lastly, the cool factor. If you’re going to post your gun on Instagram, it always looks better with a gold tone TiN coated barrel, especially if it is also fluted, dimpled, threaded, and has cool logos on it. My suspicion is that any given aftermarket barrel is probably not more accurate than the stock one, and may be much less accurate. I will discuss that more in a bit. But like I said, if you want the look, a different color or coating on your barrel will definitely enhance that factor. It looks even cooler if you have a lot of extra windows and ports milled into your slide.
If you care about accuracy then I would advise caution in purchasing an aftermarket barrel. A few years ago I tried several different brands of aftermarket barrels and most of them gave me some entertaining results in terms of accuracy and consistency. I shot several different bullet weights and types from each of them, and I found that they all had preferences in terms of bullet weight. I don’t find that same finicky behavior in the stock barrel. It is definitely true that the stock barrel may perform slightly better or worse depending on bullet weight, but the difference with the stock barrel might be only 1”-2” at 25 yards. With aftermarket barrels I found the variance to be at least double what I find with the stock barrel, and in some cases much worse. The only exception I found to the wild swings was with a KKM barrel. I didn’t exhaustively test every available barrel on the market, but I did test out four different ones. Based on my experiences, the only aftermarket barrel I will put into a Glock at this time is a KKM. I have heard from others that the Lone Wolf barrels work pretty well, but as I haven’t personally tested one of those, I can’t recommend one at this time.
In summary, if you don’t have a pressing need to replace the stock barrel, I would advise against it. If you do fall into one of the use cases I mentioned earlier, be exceptionally picky about which barrel you put in your gun, especially if you care about accuracy and function.