Our rough country in these parts is prone to critters like mountain lions, black bears and cartel smugglers. Under those circumstances, it seems like a good idea to have a bit more gun than a 9mm pocket pistol, doesn’t it? Enter the Glock 20 in 10mm. The Glock 20 is a very large pistol that forces its carriers who wear less than winter coats into some degree of open carry. (I describe my G20 OWB-under-an-untucked-shirt as “85% concealed.”) This is a gun-friendly state with a long history of open carry, and only more so outside the metro areas that contain state universities. So typically when I’m out in the boonies, I’ve got my Glock 20 with me.

Well, on a shooting trip with John Tuttle a little while back, we noticed that the old Glock was shooting left. On a later trip, I printed out the official HexSite sighting-in target and found that, indeed, the Glock was shooting about 2 inches to the left of point of aim at 10 yards. Well, a little amateur gunsmithing later, and the pistol is now… well, let’s look at the pictures.

First the “before” pictures:

Before: sight in target 1

Before: sight in target 1

Before: sight in target 2 (now with math!)

Before: sight in target 2 (now with math!)

There’s no doubt that the gun is shooting left. The results showed it was about 2″ left. After shooting, I came home and did the math on how far the rear sight needed to move. Per the formula, I drifted the sight .036 inches to the right. Or thereabouts, anyway.

Next came another trip to the range to see where the gun was now shooting:

After: sight in target 1

After: sight in target 1

After: sight in target 2

After: sight in target 2

Well! That’s a big improvement, wouldn’t you say? I did some measuring after I got home, and it looks like the gun is shooting about half an inch to the right now. I’ll probably adjust the sight base back to the left just a hair to try to dial it in better, but I’ll call that “close enough for government work” for now.

Say, while I was out, I shot some Bill Drills with the Glock 20.

Bill Drill String 1: 4/6 in 11.3 sec

Bill Drill String 1: 4/6 in 11.3 sec

I had a malfunction on this string. Partway through the string, the pistol locked open on a loaded magazine. The chamber was clear, so I slingshotted the slide and went back to work.

In the course of shooting the sight-in targets, it happened twice more, including with a different magazine and a different load of ammunition. Eventually I figured out that it was my modified form that was doing it. My higher thumb position was pushing the slide stop up and locking the slide open on recoil sometimes. I didn’t notice this problem on my Nano because the Nano has no external slide stop.

Strong-side thumb "just right"

Note the absence of an external slide stop on the Nano.

I was able to tweak the way my thumbs were riding on the pistol and avert the problem. However, at one point the pistol failed to lock back on an empty magazine, so I think that thumb positioning rode the slide stop down. Given the choice of the two, I’ll take “sometimes won’t lock open on an empty magazine” over “sometimes locks open during live fire,” but I’d prefer to have neither, so I’ll look around for a standard slide release for the pistol. (The one that came with it is an aftermarket extended slide release.)

My second Bill Drill, which I neglected to get pictures of, was a 6/6 in 5.08 seconds. 5.08 is better than I usually do from the ready position with the Nano, which I think mostly shows how much easier big guns are to shoot than small ones.

I also shot some head shots, mostly just to see how well-adjusted the sights were on a less-precise target:

Head Shots

Head shots

Say, does that bullet hole over the target’s right ear look a little odd to you? Let’s take a closer look.

Is that a keyhole?

Is that a keyhole?

That looks an awful lot like a keyhole. Commenter Jan Brink chimed in on a recent post about how large the holes are in my targets. He wondered if my bullets were going through the target sideways, or in common parlance, “keyholing.” I’m pretty sure the ones he was looking at weren’t keyholes, but rather artifacts of how the bullets move through the loosely-hanging paper. But that one? That sure looks like the outline of a bullet that went sideways through the target. Well, I’m not sure what to do about this other than just keep an eye on it. The 10mm load I was shooting isn’t terribly high quality and I’m almost out of it anyway.

Have fun and safe shooting, everyone!