Monthly Archives: May 2021

A Tale of Two Inches

In our last episode we discussed the Mauser 6.35mm and the effect of it’s three inch barrel on performance, which prompted a reader to ask about the performance of factory ammunition in a two-inch barrel .25 auto. As it happens Linda has a Colt Junior with a 2″ barrel, and I happened to have some factory… Oh. No, I don’t. But I did have some just-arrived 50gr FMC-RN bullets from PPU, so I consulted the reloading data and came up with a load I thought would approximate factory ammo.

Our test guns- Linda’s Colt Junior and my Mauser 6.35mm, and a little something extra…

As it happened I also had some Speer 35Gr Gold Dot hollow-points, so I thought I might try those as well.

Put Not Your Faith In Reloading Manuals!

Lee Precision’s reloading data suggested a 50gr. FMC-RN Loaded over 1.1gr of Red Dot would yield a velocity of 740 fps. and 61 ft./lbs. of energy. This nearly duplicates the performance of American Eagle 50gr. TMJ ammunition fired from a 2″ barrel, so that ought to do for the ‘factory ammo’ equivalent. Or so you would expect…

I set up the Caldwell chronograph and had a go. It seems Lee was a tad optimistic. From the Colt Jr.’s 2-inch barrel this gave 619 fps. and 43 ft./lbs. That’s, uh, interesting. Just for giggles I tried it from the Mauser’s 3″ barrel. Huh. 712 fps. and 56 ft.lbs. Gotta wonder what sort of gun Lee was testing this load out of…

So what was performance like in Clear Ballistics 10% ordinance gel? From the 2″ gun it was uninspiring.

Low energy, shallow penetration and the bullet tumbled and ended base-first.

9″ of penetration. The bullet did tumble and maintained a relatively straight wound track, so that’s in it’s favor. The load fared somewhat better out of the Mauser, and is reasonably close to the performance listed in the manual so it gives us a better idea how factory ammo might behave in a 2-inch gun.

The bullet didn’t tumble when fired from the Mauser, but the wound track did curve upward.

A bit over 13″ of penetration in the gel, with a slightly curved wound track. The bullet did not tumble. I think this gives a decent idea of how factory ammo would perform from a 2″ gun.

It has been noted that the FMC-RN bullet is an uneven performer in this caliber, with the round nose sometimes causing the bullet to be diverted by bones such as the ribs or skull if it does not strike squarely.

Let’s Rev It Up Some

So, about those Gold Dots… Looking over the available data I found a load tested in a 2″ Beretta, and thought that would be a good place to start. This had the 35gr GDHP loaded over 1.7gr. of Red Dot with a CCI500 small pistol primer, yielding a velocity of 946 fps. and 70 ft./lbs. of energy.

From the Colt Junior this actually gave 994 fps. and 77 ft./lbs. The bullet even mushroomed a bit.

The bullet actually expanded to approx. .337″

But there’s trouble in paradise; with low-energy bullets generally you can have expansion or penetration, pick one. This load was no exception.

Shallow penetration and a sharply curved wound-track. Not a recipe for success!

The bullet penetrated about 8″ of gel, which is generally considered far too little for reliably damaging critical structures in the human body. This does closely approximate the results of tests I’ve seen of factory Gold Dot ammo, so no real surprises here.

The Mauser’s extra inch imparted a significant improvement in velocity and energy. 1067 fps. and 89 ft./lbs., and three recovered bullets showed excellent, uniform expansion.

Bullets expanded in a range from .340 to .359″

That’s the good news. The bad news is that while penetration was better it still wasn’t good. The most expanded bullet stopped at around 7-3/8″. The other two made about 8-1/2″ and 9″. Given that 12″ is the FBI’s specified minimum penetration this must be considered, inadequate, or marginal at best.

I think I should test this load against FBI-standard and fire it through four layers of denim; I think it would actually perform better if the hollow-point was plugged and expansion was limited or prevented.

The Take-Away

Energy doesn’t tell the whole tale. The most powerful of these loads also offered the worst performance as it’s expansion limited penetration.

.25 ACP was one an extremely popular caliber for small pocked pistols, but since the GCA1968 made it problematic to import the tiny pistols that chamber it the caliber’s popularity has waned and it’s market-share has diminished. Today very few companies offer guns in this caliber. This means that ammunition companies have little incentive to improve on it, and by-and-large haven’t.

From left to right: Rimrock’s 55gr (actually 58gr.) hard-cast lead RNFP, the 35gr GDHP, and PPU’s 50gr. FMC-RN

The venerable .25 is considered inadequate for self defense these days, and not without reason. It could be useful for jobs like pest control or small game, but at it’s best it duplicates the performance of .22 LR, which is offered in guns more suited to such roles, is notably less expensive to shoot and (in normal times) more readily obtainable.

Of the rounds I’ve tested my handload using the Rimrock 55gr (actually 58gr. in the box I purchased) shows the most promise; it tracks straight in gel and penetrates consistently to about 12.5″ when fired through four layers of denim from a 2″ barrel. I also feel the hard-cast flat-point is less likely to be defected by bones in self-defense scenario.

I think a FMC flat-point, or even a a slightly concave point (to provide an edge to catch on bone and prevent deflection) weighing 55-60gr. might be the best one could reasonably do in this cartridge, but again there is little incentive to go to the difficulty and expense of developing new bullets.

A few folks have suggested that perhaps I should look into the idea of a .25 Super Auto, perhaps driving that 58gr. LFP bullet at 1150 fps. but that would require building an entire new gun to fire it, which might be a bit much. Hmmm…

Stay safe and take care.

Michael Tinker Pearce, 8 May 2021

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Mini Maus(er)

In 1896 Mauser introduced what was to become (arguably) the first commercially successful semi-automatic pistol, the C96. It was initially offered in the powerful, high-velocity 7.63x25mm Mauser cartridge, and it was a potent, flat-shooting pistol. With the addition of it’s holster/shoulder stock it could easily ‘reach out and touch someone’ at a hundred yards or more. The success of this gun helped usher in the age of semi-auto pistols.

Mauser C96, commonly known as the ‘Broomhandle’ for it’s odd grip-shape. Which frankly doesn’t look like the handle of any broom I’ve ever seen.

The gun was widely used even though it failed to land a major military contract, though many nations made relatively small purchases for military use. It continued to be produced until 1937 and large numbers were exported across the world, notably to China.

Despite quickly becoming an Icon the gun was far from perfect. It had a fixed ten-round magazine located in front of the trigger guard and reloaded from stripper-clips. It was in some ways ungainly and quirky, and by the beginning of the 20thC. sleeker, more efficient and handier guns were coming along by the bucket-load. While Mauser was happy to keep making the C96 as long as there were buyers, they felt that to be truly competitive they needed something more in-line with the emerging civilian and military markets.

They decided they should launch a family of guns, each with a common appearance, features and manual-of-arms covering everything from pocket pistols to full-sized service arms. Not at all a bad idea, and they started with a locked breech gun chambered in 9x19mm… which turned out to not be a good idea, but that’s a whole ‘nuther story. They never did get the bugs worked out of the service-caliber gun, but they kept on with the idea of the family of guns and in 1910 they introduced the first of the new line, imaginatively named the 6.35mm (the European designation for .25 ACP.) These guns are now referred to as the Model 1910, but this was never official Mauser nomenclature.

The Model 1910 .25 ACP

This was a small (but not tiny) straight-blowback pistol chambered in .25 ACP/6.35mm Auto, Jon Browning’s answer to the .22 LR for automatics. The diminutive gun featured a removable 9-round magazine carried in the pistol’s grip, a unique safety, a 3″ barrel and a wrap-around wood or plastic grip.

One of the afore-mentioned interesting features is the safety, which is identical to the Model 1914’s that we discussed in an earlier post. To engage the safety you push down on the lever behind the trigger guard on the left side of the gun. To release it you press the button just below the lever. It’s not hard to learn and is kind of neat.

The slide locks open after the last shot… and it’s stays locked open until you insert a fresh magazine.

Another feature it shares with the Model 1814 is the slide lock, somewhat unusual on a .25 auto. It locks open after the last round in the magazine is fired. In fact it will lock back if you rack the slide when there is no magazine in the gun. The only way to get the slide to drop back into battery is to insert a new magazine, whether the magazine is loaded or not. Of course if it is loaded the gun will chamber a round when the slide closes. This was intended to facilitate rapid magazine changes, but some people find this irksome, though I don’t mind it. Even though Mauser continued this system in their later HSC it never really caught on with other manufacturers.

Even in the early days of semi-automatic pistols this was a bit of an odd duck; not as compact as most other .25 ACP pistols, not as potent as slightly larger .32 and .380 autos. This did not seem to dissuade buyers, however; over the next few decades they sold almost half a million across all variations.

There were several of these, making aspects of the pistol easier to produce or more efficient, but it remained unchanged in essentials throughout its run. Production ceased at the outset of WW2, and the now rather antiquated design did not resume production after the war.

So how do you like it, Tinker?

Very well indeed, actually. It’s small and flat enough to conceal easily, but the grip allows me a solid two-finger hold that is much more comfortable and secure than most .25s. The trigger has a lot of take-up, but is light and crisp when you eventually get there; both Linda and I were quite impressed. It’s quirky, interesting, comfortable to hold and easy to manipulate. It even has surprisingly decent sights for a pistol of its era. What’s not to like?

Here’s the Mauser compared to a more typically-sized .25 auto, Linda’s Colt Junior.

Well, it’s rather heavy for it’s size; it is solid steel after all. Still, 14.6 ounces unloaded isn’t what anyone would call a heavyweight; certainly not a person such as me, who was raised when Men were Men, guns were steel and sheep were nervous. Still, there are snub-nosed .38 revolvers this light or lighter, and in these 21st century days of polymer uber alles it’s hefty for a pocket pistol.

This particular example is in excellent condition, with all of it’s original finish, though this is marred in some places with minor speckling. The bore is very good, with only a slight ‘frosting’ of the grooves.

So then, how’s it shoot?

I haven’t much ammo on hand; not enough for a proper test, certainly. Reloading components are on the way, so a full range-report will have to wait until they arrive and I have a chance to load more. I did test hand-cycling from the magazine, which is fine, and I fired eight rounds for testing purposes, again with perfect results. The gun is just large enough to sit well in my hand in a two-fingered grip, the sights are decent and the trigger is truly excellent- so much so that it will catch you out if you aren’t careful.

Accuracy remains to be seen, though at three yards the bullets hit exactly where I aimed them. Recoil was, as you’d expect, negligible, and the gun didn’t shift in my hand even slightly when firing. I expect this pistol will be very accurate in rapid-fire.


Typically pistols chambered in .25 auto have a 2″ barrel, but the Mauser has a 3″. You’d expect that extending the barrel by 50% would have an effect on ballistics, and you’d be correct.

My standard .25 ACP load is a 58gr hard-cast lead flat-nose bullet over 1.1gr. of Red Dot with a CCI 500 Small Pistol primer. When I tested it in ‘The Battle of the Mouse Guns’ this gave an average of 646 fps. and 54 ft./lbs. of energy; this is not at all a ‘hot’ load for this caliber. The same load from the Mauser did an average of 729 fps. and 68 ft./lbs. This is a 26% increase in power; not a huge difference, but at these low levels of energy every little bit helps. Alright then, how much does it help? The answer is rather surprising.

Bullets were fired from the left end to the right end.

From the 2″ barrel of the Colt Junior penetration was 12.5″ in Clear Ballistics 10% ordinance gel. In contrast they penetrated considerably further when fired from the Mauser. One bullet exited the top of the block at 8″ and struck the steel backstop hard enough to significantly deform the bullet. One bullet stopped nose-forward at 15″. The remaining six rounds all passed entirely through the 16″ long block.

After it became apparent the bullets were exiting the block I added another, placed a small block behind it, which rested at an angle owing to it’s shape. One bullet embedded itself an inch deep in this after exiting the main block. Three other bullets passed through the smaller angled block on paths that traversed 2-3″ of gel before striking the back-stop. I was surprised to say the least!

Recovered bullets showed little distortion, except for the bullet on the right, which exited the top of the block at 8″ and struck the steel backstop. I have been unable to account for the bullet fragment next to it, which was sticking in the back of the block.

The bullet is 16% heavier than the standard 50gr FMC-RN normally used in this caliber giving it significantly higher sectional density, which enhances penetration out of proportion to the increase in energy.

I think further testing is needed when I have more ammo reloaded, and I’ll perhaps try a variety of bullet types. I’ll have 35gr. XTP hollow-points and 50gr. FMC to try then.


This is a delightful little pistol, and I can see why it sold well. It’s much easier to manage and fire accurately than typical, smaller .25s, especially for someone like me with rather large hands, and the negligible recoil would have been much in it’s favor for inexperienced or occasional shooters.

Would I carry it? Around the property, where rats have occasionally showed their pointy little noses, sure. As a self-defense weapon? I reckon if you find an 8-shot J-frame .22 adequate this would serve you as well or better, but let’s be realistic. This is a century-old gun in an anemic caliber; you’d be better off not.

On the other hand as a fun little plinker with a bit of history you could do a lot worse, and with ammo prices and availability they way they have been I can reload .25 ACP cheaper than I can buy .22LR… if I can find any.

Take care and stay safe.

Michael Tinker Pearce, 3 May 2021

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