by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1
Part 2

Diana 25
The Diana 25 (this one says Winchester 425) was made for decades. It’s at the top of the youth line of air rifles from the ’50s through the ’70s.

Today, we’ll learn how accurate a vintage Diana model 25 breakbarrel air rifle, in the form of a Winchester model 425, can be. I have to tell you, days like this are pure candy to me! Shooting a smooth vintage air rifle is so relaxing. Since they’re no longer sold, I don’t have to scramble to shoot my best, because only a collector will ever buy one. On the other hand, these lower-powered spring guns mostly out-shoot the modern guns anyway, at least at short distances, so even shooting relaxed I do pretty well.

We all agreed that the model 25 is a close-range plinker, so I shot from 10 meters. I used a 10-meter pistol bull since I was using the open sights that come with the rifle. By strongly lighting the target and keeping the room I’m shooting in dark, the sights appear sharp against the target. I normally don’t like the German Dachkorn-type front sight, which is a V-shaped post; but under these circumstances, it worked very well. Incidentally, I’ve always referred to this as a Perlkorn; but while researching this report I discovered that the Perlkorn has a bead on top of the tapered post.

Sitting down at the bench to shoot reminded me of just how easy this little rifle is to cock. The barrel goes down butter-smooth, and it takes onlyΒ about 14 lbs. of force to do it. But when I brought it back up after loading, I discovered that the pivot bolt was a little loose. The barrel wouldn’t stay in one position after the rifle was cocked. It flopped back down again. That’s a sign that the pivot is too loose, which leads to a loss of air at the breech. I decided to tighten it, and that lead me to another wonderful feature of the Diana 25 — the pivot bolt has a locking screw!

Diana 25 barrel pivot bolt locking screw
The head of the barrel pivot bolt (larger slotted head in the photo) is cut out around its edge to receive the smaller head of the locking screw. Once set, this bolt will not get out of adjustment.

The pivot bolt has cutouts around its edge to accept the head of a smaller locking screw. Once you set the bolt where you want it, put the locking screw in and the setting will never move. This is one of those seemingly insignificant features that we overlooked when rifles like this were new, yet Β today even the most expensive pellet rifles don’t have it! In fact, a good number of the current guns don’t even have a pivot bolt — they use a plain pin that can never be tightened.

RWS Superpoints
The first pellet I shot was the .22-caliber RWS Superpoint. I mentioned in an earlier report that I like the Superpoint for its thin skirt that gets blown out into the sides of the bore when the rifle fires. Other pellets are either too hard, or their skirts are too thick to deform with the relatively light puff of air from the model 25’s piston. The Superpoint, though, should work well in a gun like this.

The distance was 10 meters and I shot from a rest, so this report is about the rifle’s capability and not the shooter’s. That crisp ball-bearing sear was a real pleasure to use, and I didn’t waste a lot of time setting up each shot.

I used the sights exactly as they were set when I got the rifle. Remember that my friend Mac was the former owner, so it came as no surprise when the pellet landed exactly at the aim point — a 6 o’clock hold on the bullseye. After seeing the first pellet was where it needed to be, I didn’t look at the target again until the 10th shot had been fired. What I saw then was a surprise — even when I had been expecting good results. Ten RWS Superpoints went into a group that measures 0.613 inches between centers. It’s a one-hole group that looks smaller than it really is because the pointed pellets allowed the paper to return to its normal dimensions after they pass through. This is the same kind of accuracy I used to get from the Hakim trainers at the same 10 meters.

Diana 25 breakbarrel spring-piston rifle--RWS Superpoint pellets

Ten RWS Superpoints made this 0.613-inch group at 10 meters. It’s larger than it looks because the paper flapped back after the pellet passed through.

The next pellet I tried was the RWS Hobby. This is another pellet that’s often very good in rifles that shoot at lower power. And by being fairly light, at 11.9 grains, it has the advantage of traveling faster than most other pellets. Ten Hobbys grouped in 0.538 inches between centers. It was another one-hole group. Nothing to do but to smile and hope the rifle continues to shoot like this!

Diana 25 TWS Hobby target
Ten RWS Hobbys are even tighter, making this 0.538-inch group.

The last pellet I tried was the JSB Exact RS dome that weighs 13.4 grains. I hoped that this pellet might shine in the little 25 in the same way the .177 version does in my Beeman R8. Well, shine it did, putting 10 of them into a group that only measures 0.38 inches between centers. Does that explain why I like shooting these little vintage spring guns so much?

Diana 25 JSB Exact RS target
The JSB Exact RS dome was the best pellet of all. Ten made this 0.38-inch group at 10 meters.

Deformed pellets?
The Diana breakbarrels all have slanted breech faces; and when the barrel is closed, if the pellet isn’t seated flush all the way around the skirt, it can catch on the action and slightly bend the rim of the skirt when the barrel’s closed. This was happening with all three pellets used in this test. So I shot a fourth group of 10 with the most accurate pellets (JSB Exact RS) seated deep in the breech. I wanted to see what effect this would have, if any.

Diana 25 pellet in breech
Because the breech face is slanted, the tip of the pellet skirt sticks out like this when the pellet is seated.

Diana 25 deformed pellet
When the breech is closed, this is what happens to the pellet. It doesn’t seem to hurt accuracy.

Diana 25 JSB Exact RS target pellet seated deep
Seating pellets deep in the breech (JSB Exact RS used) opened the group up and also dropped the point of impact about one inch at 10 meters.

Deep-seating didn’t work this time. The group of 10 JSB Exact RS pellets opened to 0.615 inches. It also dropped the point of impact about one inch at 10 meters. Doesn’t seem like it’s worthwhile.

The end?
I sure hope this isn’t the last report I get to do on this air rifle. What a joy it is to shoot something that’s accurate, has a great trigger, is quiet and is easy to cock. I know you have to buy these used, but it’s worth the effort, in my opinion. It doesn’t replace your modern magnum air rifles, but it gives you something to do when you just want to shoot without a lot of fuss. If you’ve enjoyed reading this report, remember that there are three different models of the Diana 25. Only two of them have the ball bearing sear, so be careful when you look for one.