Faith, Family, Friends and Firearms

Diana Model 25

There is not much information on the internet about the Diana Model 25 air rifle. It is a youth model, low powered and the originals were made prior to and perhaps during the initial years of World War II. I’m documenting the attempted resurrection of one of these rifles. Perhaps this information will be of use to someone out there.

The rifle came to me with a bent barrel. It’s not the typical upward bend resulting from the barrel being allowed to snap close under the power of the main spring. It is bent heavily to the right, to the point where the owner tells me that a pellet would get stuck in the barrel.

Barrel against the wall, showing decided bend to the right.
Other side of the barrel against the wall, showing the bend.

From the breech end of the barrel, you can see how crooked it is inside.
The breech seal is the old leather type, it appears to be in fairly good shape. We’ll have to hydrate it with silicone oil and see if it leaks when fired after reassembly.
Here are the major components of the rifle. The only thing left to disassemble would be to remove the sights and the piston seal. The sear will be left in the trigger assembly. There was quite a bit of precompression in the spring. The full length of the trigger block was under compression. The spring is 0.110 wire with 30 coils and 0.500 inside diameter. But it appears to be in great condition, no need to replace it at this point.
Left side of the receiver. This picture and the following ones detail the effects of long term neglect in a humid climate. There’s a lot of rust and someone took some coarse sand paper to it some time back. “Rode hard and put away wet” is the way some folks describe this condition.
One can barely make out “Made in Germany” on the left of the receiver.
A lot of corrosion, you can see the scratches from the coarse sand paper. Diana is there, but not easy to make out. The writing is more legible in the pic than it was in person.
It was difficult to remove the piston seal. The screw was held in place by a drift pin. It took nearly 40 inch pounds of force to get it loose – there appears to be a flat on the side of the screw threads that was either filed or merely deformed by the force of seating the pin. Don’t know if I’ll be able to find a replacement or if we’ll appeal to thread locker upon reinstalling. The piston seal is in excellent shape, now soaking in silicone oil to rehydrate and prepare it for reassembly.

A Few Days Later

The compression tube/receiver after being polished to remove most of the rust. There’s still some light pitting and discoloration from the years of neglect. I rubbed it down with some Brownell’s Oxphobluing (I THINK that’s what it’s called) and the resulting finish is splotchy (as expected) but not too horrid – much better than the rust and such.
You can see the “Made In Germany” stamp fairly clearly now.
The piston reassembled. The leather seal sat in silicone oil for a few days to rehydrate after years of being stored. It all went together smoothly.
One thing that “popped out at me” almost literally – the pin that locked the screw in place from the factory got cammed out a bit when I forced the screw loose. Of course, the piston would NOT slide into the tube that way. Used a tool to set the pin back against the screw, it should be good to go now.
The trigger after being sanded to remove the rust.
It blued up nicely.

After a bit of proper lubing of the spring and other parts, the rifle was reassembled. I’d had some doubts about the process, but over on the Gateway To Airguns forum Jon “eeler1” posted a link to a video about a similar rifle. This one is a Winchester 422, and looks like a dead ringer for the Model 25. It’s actually a Diana Model 22, but I don’t know what the differences are between the two models. I’d not checked out the NorthWest Airgun channel in a while. He’s got some other good stuff over there. Worth taking a look if you’re interested in airguns. Anyway, he did three videos on his grandson’s rifle – and that was a big help as when he reassembled he showed me how to do the trigger. I’d been over thinking it and was planning to make a slave pin for the trigger. That would NOT have worked. When I saw him put it together things clicked in my brain and sure enough, it’s not as hard as I thought it was. There was some kind of hangup, but eventually I got it together properly and voilá! The rifle shoots!

I took the first five shots from a free standing position. The light little rifle is easy to cock and shoulder and the trigger isn’t too horrible either. But the sights. Oh, brother! The sights are not very compatible with a tan background, low light and my aging eyes (that were never that good to start with). Still, it seemed like the rifle was shooting to the right still. The center hit on the “bullseye” was a called flier. Pellets are some old RWS pistol wadcutters.
So I ran another 10 shots for a total of 15 and sure enough, it was hitting to the right fairly consistently, and a bit low as well. So out came the precision sight adjuster (tack hammer and brass rod) and the front sight was moved right and the rear sight was moved left and at 7 meters (give or take) the following target resulted.
Five shots at around 7 meters. Not too shabby if I do say so myself. Considering that this rifle wouldn’t even let a pellet through the barrel, I’m pretty tickled with results so far.
Aim small, miss small. I broke out a small black bullseye printed target and proceeded to shoot from 10 meters. Not very good. Hmmm. Moved back to 7 meters and the point of impact raised a bit, but it’s still not a target rifle. Still, I’m tickled to have it shooting.
The Diana Model 25
And the other side.

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11 Comments

  1. Roadworthy

    Thanks for sharing. I found the differences between that gun and my 1969 Model 35 noteworthy. I haven’t gotten the cap off the rear of the compression tube to disassemble my gun yet. It was in a wet climate, too, and I suspect rust is holding it together.

    • paul

      Well, I updated the post today. The rifle’s together and functional. We’ll see how it develops from here. 🙂

  2. TF89

    Jumped here from the GTA site. Great pictures, looking forward to the rest of the story as it unfolds.

    Good luck on your mission.

    • paul

      Thank you! Take another look at it, I updated the post this afternoon.

  3. gary christy

    I have inherited a Diana model 27 British made post war. 50’s or 60’s. It does not hold
    the cocked position. I would like to get it into shooting condition. I need a source for
    parts and a good schematic. Please email me
    Gary J. Christy
    bootsm1@aol.com

    Thanks

    • shahta

      Hi
      The triger had a griper which could be round after too many shots .it,s mechanism is very simple if you open it you can fix it by rasping

  4. Garry Brischke

    Very informative. My Gecado 25 is possibly a clone. I am having trouble removing the drift pin that secures the piston washer screw. Any hints would be appreciated.
    gbrischke@gmail.com

  5. Dennis

    Hi,
    My name is Dennis from Indonesia. I’ve just found the same product but the original mainspring is not available here. Please let me know the length of the mainspring since I’ll make an attempt tp find its alternative.

    Best,
    DI

    • Hi, Dennis. I do not know the length of the spring. The information I have is as follows:

      The spring is 0.110 wire with 30 coils and 0.500 inside diameter.

      Those 30 coils include the two collapsed coils at the ends of the spring. The critical dimensions in recreating such a spring are the wire diameter and the inside diameter. If you get those two right then the rest should work out OK. Take a look at the picture of the spring and inside components. With your rifle apart you can calculate the length approximately by comparing the length of the spring guide to the spring in the picture. It appears (at first glance) that the spring in its uncompressed state is roughly two and a half times the length of the spring guide.

      If you have a spring made, you’ll want it to be snug but not TOO tight on the spring guide. This will reduce the sound of the spring and will give it the best guidance to provide longevity of the spring.

  6. Amit

    Hello Paul,

    Thank you for this informational article, I also have similar model 25 airgun gifted to me by my Grandpa, it was in state of neglect for 2 decades and I am trying to restore this gun, I need a new stock for my gun however I am very confused with the wood type. by any chance do you know about the type of wood used for stock.

    Thanks again for this wonderful article.

    • I’m glad the article was of service to you, Amit. Unless you can find a used stock somewhere you will need to have one made from scratch. I BELIEVE the original stock is some kind of European walnut, but am not sure. That being said, a number of different kinds of lumber will work, depending on what you have available. Over the years I’ve made stocks from Brazilian Mahogany, Jatobá (another Brazilian hardwood) and have a piece of abarco (I THINK that’s what it’s called) drying for future use. You need a type of wood that is tough and not too hard to work. The Diana 25 isn’t a hard kicking rifle so you don’t have to worry like with some guns about the possibility of the wood splitting on you when cocking and firing the rifle – as long as you select a good grade of timber and are careful about stock layout.

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