I had a couple of 12-gauge doubles I wasn’t interested in anymore and stopped by Pinto’s to see what they’d give me for them and… well, Pinto’s. I spotted something in the case, then Linda looked at it and thought it was adorable and that’s all she wrote.

In the first half of the 20th C. the .25 ACP cartridge was very popular for tiny semi-auto pistols for self-defense. Designed by John Browning as a center-fire, more reliable cartridge than .22 Rimfire for pocket autos the .25 ACP is now largely obsolete. It was always frankly pretty marginal as a defensive cartridge, but the guns were so small and convenient people seemed to think the trade-off was worth it.

Frantisek Dusek was a Czech gunmaker and importer. Initially he imported Spanish pistols, mainly copies of the Colt 1908 Vest Pocket like the Ydeal. In 1938 he began production of his own pistol, the Duo. This was a near-copy of the Colt, but lacked that pistol’s grip safety.

When the Nazis invaded Czechoslovakia in 1938 Dusek refused to cooperate with them, and the Germans took over management of the factory. The small pistol was popular with Nazi officers (though they had to purchase them for themselves) and to select civilians under their rule. The pistols could be purchased with a leather flap holster that held the pistol and a spare magazine for wearing on a uniform belt. By the end of the war the factory had produced 110,000 of these guns.

After the war production continued, and in 1948 the factory was nationalized. At that point these became CZ Duos. All told these pistols were made for around 50 years before being discontinued.

The pistol is a single-action striker-fired blowback pistol. It has a six-shot magazine and a manual thumb-safety that is also used to disassemble the gun. The hard-rubber grips have a basket-weave pattern and a molded medallion with the word Duo in the center.

To disassemble the pistol you remove the magazine, set the safety, rotating it 180 degrees to the rear, then you withdraw the slide until safety clicks up into a recess and locks the slide about 1/2 from being in battery. You can then rotate the barrel 90 degrees to the side, release the safety and move the slide forward off the pistol. Care should be taken to insure the springs for the striker and main recoil spring don’t depart for places unknown.

Last evening I popped out in the shop and loaded some ammo for it. I used a 55gr. LFP bullet over 1.1gr. of Red Dot with a Federal small pistol primer. This afternoon I set out for the range to have a go.

Shooting the Duo

First impression is that this is a very well made little pistol; it gives up nothing in quality to the Colt and FN pistols it was copied from. The magazine has witness holes and is pretty easy to load. The sight, if it can be dignified with that term, is a simple groove running down the top of the slide to the muzzle so aimed fire isn’t really this gun’s forte.

This gun was designed to be used at an arms-length, so to start I ran a target out to 3 yards. I loaded the gun and blazed away one-handed, as fast as I could pull the trigger without aiming.

Accuracy was, um… OK, it was non-existent. Sure, you wouldn’t want to be on the receiving end, but yeah, it works about as well as you’d expect. Next I tried aiming using the groove and that went rather better.

Even though it’s not really intended for it I ran a target out to seven yards and fired one shot per second, again trying to aim.

It’s not going to win any bullseye matches, but it’s seriously not too bad. If it had proper sights I suspect it would be pretty accurate. Recoil was basically non-existent, as you might guess, and the trigger pull isn’t bad at all. Even though I have large, meaty hands the gun did not pinch or bite anywhere. It’s really very pleasant to fire. Over the course of fifty rounds there was not so much as a bobble; the gun seems quite reliable.

This is a nice little gun. It’s cute, it’s fun and I am very happy we got it. No, it ain’t gonna drop a bull elephant (or even a really big squirrel) in it’s tracks but I like it.

Stay safe and take care.

Michael Tinker Pearce, 19 December 2021

If you like what you see here please consider clicking the link above and supporting me on Patreon.

This might be the fastest ‘next post’ in a series ever. In the last post I mentioned the keyholing issue, which first made itself known firing Aardvark Bullets cast 124gr. RNL. I briefly considered that it might be these bullets, as I have had other Aadvark bullets with an inexplicable tendency to key-hole. Nah, I thought, what are the odds?

In response to my previous post today a couple people suggested that opening the sides of the weight might relieve the shockwave in the tube and keep the bullets from destabilizing. What the hell, it can’t get more broken, right? I locked the weight down on the drill-press and punched me some holes, then headed back to the range to see what would happen.

What happened was interesting. With the 124gr JHPs over 5.8gr of Unique groups were tighter and fewer bullets Key-holed. The tighter group indicates that the bullets were yawing less; the more they yaw the bigger the spread. There seems to have genuinely been a positive effect on the Jacketed bullets.

OK, not perfect but it’s a step in the right direction. Let’s see how the 124gr. cast bullets fare.

Poorly, as it happens. Every single bullet key-holed. Hmmm… my Spidey sense was tingling. I loaded an eight-round magazine for my Sig-Sauer P6 and took a few shots.

Every bullet key-holed. Against expectations the Aardvark 124 gr RNL lead appear to be crap. I couldn’t test the jacketed bullets through the Sig because I’d fired them all, but it looks like I need some new bullets to try, and this time I need to make sure that damn things fly straight before I test them in the project gun!

A bit of a roller-coaster day, but it appears this project is not dead yet. Stay tuned for further developments!

Stay safe and take care,

Michael Tinker Pearce, still 16 December 2021

My 9mm project was a pretty cool idea, and it sort of works… but it very much doesn’t also. Once I got it working reliably enough to pay attention to accuracy I noticed there was an issue. Bullets are keyholing at seven yards. This is not conducive to accuracy…

This did not happen before the dust cover was extended and the weight added, which narrows down the search for the cause. It turned out that while I had been careful to insure the hole in the weight was well-centered on the barrel I had not accounted for the fact that the barrel points slightly downward when locked up. After exiting the barrel the bullets were coming quite close to the lower edge of the opening in the front of the weight. It seemed likely that the muzzle-blast within the confined interior of the weight was exerting asymmetric force on the bullets, causing them to tumble.

OK, I can fix that. I honed out the inside of the weight so that the bullet will remain centered in the ‘tunnel’ until it exits the weight. Time to test fire…

No-go. Bullets are still not flying true. Something is awry, and it’s something to do with the weight. Bugger.

There are several options at this point, and some question about where I go from here. The issue isn’t that I wanted a fast ‘race gun.’ I wanted to see if a specific concept, a short slide and barrel with an extended fixed weight, would work. It looks very much like it doesn’t. From that perspective the gun is a complete success; it answered the question. It wasn’t the answer I wanted, but that’s really not the point, is it?

I invested over $800 in this gun so far (if one includes magazines) and I am not going to let that go to waste. It will become a useful, functional gun. The question is what kind of useful, functional gun? The options for using a fixed weight with a full-length barrel have pretty much been explored and compensators proved to be a better mousetrap, so there’s not really any new ground to break there.

Not sure what’s next for this project, but whatever it is will I’ll have fun doing it.

Stay safe and take care.

Michael Tinker Pearce, 16 December 2021