I had a little extra cash at Christmastime after selling some of my guns and saw this Heckler & Koch Mark 23 for sale at Wanstalls. It was used—2800 rounds worth—but fairly priced so I picked it up. I’ve been a little up and down on H&Ks over the years…I’ve owned six I think…but right now I’ve got none, and the Mark 23 has always intrigued me. I received it last week and hoped to shoot it but the 30cm of snow we had this week put those plans on hold, so I thought I’d take a deeper look at the pistol.
Background
The Mark 23 was originally designed in the early 1990s as an “offensive” handgun for the USSOCOM, as compared to the defensive role a handgun usually plays. High accuracy, durability, and the ability to accept suppressors and Laser Aiming Modules (LAMs) were all specified. Production started in 1996. From what I’ve read, the pistol was not met with universal acclaim with the intended users, mostly due to its large size and weight; it’s hard to argue that this pistol does the job better than newer, more compact models.
Size
The first things you often hear about the Mark 23 is how big it is—how it’s a “crew-served weapon”. For sure it’s big…but not that big. It’s 9.7” (24.5 cm) long and weighs 43 ounces (1.2 kg). That’s big, but a Smith & Wesson 686 .357 Magnum revolver with a 4” barrel is 9.6” (24.3 cm) long and weighs 40 ounces (1.1 kg), and you don't hear how unmanageable they are. No question, though, it’s large compared to similar semi-auto pistols. Here’s how it looks compared to a Glock 21SF and Beretta 92SF.
and here’s how they compare from the back—not a whole lot of difference other than overall height.
I checked a few dimensions on all three pistols and came up with the following:
Grip Circumference (measured immediately below the trigger guard):
Trigger Reach:
Bottom line: big, yes. But, if you can handle a typical large-frame semi auto you’ll have no issue. I’ve got small hands and can manage—although the DA reach is about as long as I can accommodate.
Overview
The Mark 23 is a traditional tilting barrel locked-breech semi-auto pistol—nothing earth-shattering there. Here’s the barrel and recoil spring:
You can see the green rubber O-ring near the muzzle end of the barrel. This supposedly helps tighten up barrel lock-up to improve accuracy. H&K also has this feature in the HK45 and some of the USP models.
And here they are compared with the barrel and recoil spring from a Glock 21—the Mark 23’s recoil spring is certainly stout!
Here’s the insides of the frame—I was impressed and how there’s almost no wear on the parts:
The steel cable part is actually the trigger bar return spring.
Sights
Sights are typical three-dot sights.
The sights are raised up from the top of the slide—I’m guessing to allow for their use with a suppressor. The rear sight is windage adjustable. I am not super-crazy about three-dot sights—I generally find the rear dots too distracting. I may black them out—I’ll see how these fare at the range.
Controls
The controls are a little unusual.
The magazine release is H&K’s typical ambidextrous paddle release. I like these a lot—with my short fingers I can reach the release easily with my trigger finger without having to change my grip.
There’s a 1911-style safety at the rear of the frame, and also a separate decocker immediately in front of the safety. The safety is easy and positive to operate in either direction, but smaller than a typical 1911 safety, while the decocker is quite thin and not that easy to manipulate. I would not want to have to use it quickly under stress!
I think the combination safety-decocker that USPs and the HK45 have would be a better bet. I’ve read that the separate controls were part of the original specification for the pistol (it does have a reputation of being “designed by committee”).
There’s a threaded hole in the front of the trigger guard to accommodate the LAM.
The trigger is nicely grooved—I really like it.
I’ve dry-fired the pistol a bit—the SA trigger is very reminiscent of the USP Expert trigger. It’s very crisp with just a wee bit of creep at the start of the pull. The reset is short and positive, and the break point is right at the reset point, too. I much prefer this trigger over the HK45’s. The DA pull is heavy, but pretty smooth, and only has a slight stacking at the end of the pull.
Preliminary Conclusions
It’s big but manageable, and balances very nicely in the hand—it’s very neutral without any real tendency towards muzzle-heaviness. There’s more steel in then frame than many polymer-framed handguns and that helps minimize the top-heaviness some. It is a noticeably tall handgun, with the sights quite high…but still less than on a double-action revolver. The grip is less ergonomic than it's spiritual successor, the HK45, but feels more positive to me; the HK45 grip has always had a "slippery" feel to me despite its texturing.
I’ll update the thread once I've had some range time.


Background
The Mark 23 was originally designed in the early 1990s as an “offensive” handgun for the USSOCOM, as compared to the defensive role a handgun usually plays. High accuracy, durability, and the ability to accept suppressors and Laser Aiming Modules (LAMs) were all specified. Production started in 1996. From what I’ve read, the pistol was not met with universal acclaim with the intended users, mostly due to its large size and weight; it’s hard to argue that this pistol does the job better than newer, more compact models.
Size
The first things you often hear about the Mark 23 is how big it is—how it’s a “crew-served weapon”. For sure it’s big…but not that big. It’s 9.7” (24.5 cm) long and weighs 43 ounces (1.2 kg). That’s big, but a Smith & Wesson 686 .357 Magnum revolver with a 4” barrel is 9.6” (24.3 cm) long and weighs 40 ounces (1.1 kg), and you don't hear how unmanageable they are. No question, though, it’s large compared to similar semi-auto pistols. Here’s how it looks compared to a Glock 21SF and Beretta 92SF.

and here’s how they compare from the back—not a whole lot of difference other than overall height.

I checked a few dimensions on all three pistols and came up with the following:
Grip Circumference (measured immediately below the trigger guard):
- Mark 23: 14.6 cm
- Beretta 92FS: 14 cm
- Glock 21 SF:1 4.4 cm
Trigger Reach:
- Mark 23: 7.4 cm
- Beretta 92FS: 7.3 cm
- Glock 21 SF: 7.3 cm
Bottom line: big, yes. But, if you can handle a typical large-frame semi auto you’ll have no issue. I’ve got small hands and can manage—although the DA reach is about as long as I can accommodate.
Overview
The Mark 23 is a traditional tilting barrel locked-breech semi-auto pistol—nothing earth-shattering there. Here’s the barrel and recoil spring:

You can see the green rubber O-ring near the muzzle end of the barrel. This supposedly helps tighten up barrel lock-up to improve accuracy. H&K also has this feature in the HK45 and some of the USP models.
And here they are compared with the barrel and recoil spring from a Glock 21—the Mark 23’s recoil spring is certainly stout!


Here’s the insides of the frame—I was impressed and how there’s almost no wear on the parts:


The steel cable part is actually the trigger bar return spring.
Sights
Sights are typical three-dot sights.



The sights are raised up from the top of the slide—I’m guessing to allow for their use with a suppressor. The rear sight is windage adjustable. I am not super-crazy about three-dot sights—I generally find the rear dots too distracting. I may black them out—I’ll see how these fare at the range.
Controls
The controls are a little unusual.

The magazine release is H&K’s typical ambidextrous paddle release. I like these a lot—with my short fingers I can reach the release easily with my trigger finger without having to change my grip.
There’s a 1911-style safety at the rear of the frame, and also a separate decocker immediately in front of the safety. The safety is easy and positive to operate in either direction, but smaller than a typical 1911 safety, while the decocker is quite thin and not that easy to manipulate. I would not want to have to use it quickly under stress!
I think the combination safety-decocker that USPs and the HK45 have would be a better bet. I’ve read that the separate controls were part of the original specification for the pistol (it does have a reputation of being “designed by committee”).
There’s a threaded hole in the front of the trigger guard to accommodate the LAM.

The trigger is nicely grooved—I really like it.

I’ve dry-fired the pistol a bit—the SA trigger is very reminiscent of the USP Expert trigger. It’s very crisp with just a wee bit of creep at the start of the pull. The reset is short and positive, and the break point is right at the reset point, too. I much prefer this trigger over the HK45’s. The DA pull is heavy, but pretty smooth, and only has a slight stacking at the end of the pull.
Preliminary Conclusions
It’s big but manageable, and balances very nicely in the hand—it’s very neutral without any real tendency towards muzzle-heaviness. There’s more steel in then frame than many polymer-framed handguns and that helps minimize the top-heaviness some. It is a noticeably tall handgun, with the sights quite high…but still less than on a double-action revolver. The grip is less ergonomic than it's spiritual successor, the HK45, but feels more positive to me; the HK45 grip has always had a "slippery" feel to me despite its texturing.
I’ll update the thread once I've had some range time.
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