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

Part 1
Part 2
Part 3

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

On Friday, I tested the Chinese Fast Deer sidelever rifle at 25 yards, and in doing so I started the juices flowing again for the vintage airguns. One remark I made in the report was that I thought the Fast Deer might be more accurate if I fitted a peep sight in place of the open sights that are on it now. That got me thinking about other low-powered spring guns I’ve recently tested — including the Winchester 425, which is a Diana 25 by another name.

I tested the 425 at 10 meters because it has open sights and also because of the low power level. It’s a .22-caliber spring rifle that shoots in the low- to mid-400s, and long-range accuracy is not its strong suit. But after seeing the Fast Deer perform, I began to wonder how the 425 might do if I tried it with a peep sight. Kevin recommended trying it, and I was happy to take his suggestion. We always talk about how peep sights improve the aiming situation, so a peep sight ought to have some impact on even a rifle like this one.

As it happens, I have a peep sight that attaches to the rear sight base on many vintage Diana air rifles, including this 425, so it was easy to remove the open rear sight and attach the peep. I left the open sight in place until the peep was firmly anchored to the base, then I looked through the peep and adjusted it until the open sight picture looked perfect through the peephole. That told me the peep was looking at the same place as the open sight, so no special sight-in procedure was required.

Diana 25 peep sight
The Diana peep sight fits the model 25 as well as many of the larger models. It looks simple but delivers on target!

The Diana peep sight is vintage and appears less sophisticated than the target peeps we see today; but when you use it, you soon learn that it’s as nice as any of them. It has crisp detents with very visible scales for both adjustments plus the directions are also on the adjustment knobs. They’re in German, though, so they’re the reverse of American adjustments. The sight sits low on the spring tube and is shaped to conform to the contours of all Diana rifles, so there’s very little clearance between the sight and the gun. The sight does extend back, which is helpful, but as small as the 425 is, I still found it difficult to get as close to the eyepiece as I would have liked. That’s because the stock’s pull is a sporting length instead of a target length that would be several inches shorter.

JSB Exact RS
Since JSB Exact RS domes had proved to be very good at 10 meters, they were the first pellet I tried at 25 yards. I trusted that the pellet would go to the point of aim and it did. The first shot was right on target, but there was a small problem because I was trying to use 10-meter rifle targets and the bull is too small for me at 25 yards. So, I replaced the target with a 10-meter pistol target and afterward everything was fine.

The first group of 10 pellets measures 1.059 inches between centers. Now, that sounds like a big group; but if you look at the target, I think you’ll see that it really isn’t so bad. Seven of the 10 pellets landed in 0.545 inches and that’s good.

Diana 25 RS target
The JSB Exact RS pellet made a large group, but there’s a much smaller group within. This shows promise.

RWS Superdomes
Another pellet that did relatively well in the 10-meter test was the RWS Superdome. And this is where the difference between 10 meters (11 yards) and 25 yards really shows! Ten Superdomes went into 1.349 inches, and the group appears scattered left and right. This is not a pellet I’d use in this rifle at this distance.

Diana 25 Superdome target
RWS Superdomes were generally scattered left and right. Not a pellet to pursue.

Here is another example of why a 10-shot group is so much more valuable than several 5-shot groups. You could get lucky with several 5-shot groups and never know how well the rifle really shoots, but a single 10-shot group tells the tale very clearly. In the end, it saves time and pellets.

Notice that Superdomes struck the target lower than the JSB RS that preceeded them. So, I adjusted the rear sight to hit higher on the target following this test.

JSB Exact 14.3-grain domes
Next, I tried some JSB Exact Jumbo Express 14.3-grain domes. Since the RS pellets had done so well, I thought these might do well, too, even thought this pellet has disappointed me very often in the past. For some reason, the RS and 15.9-grain pellets shoot rings around this one, and I don’t quite know why.

The Diana 25 doesn’t like them, either. Though the group is well-rounded, the shots seem scattered within it. The group measures 1.288inches between centers and there is nothing to give much hope of any better performance.

Diana 25 JSB Jumbo Express target
JSB Jumbo Express group is even more scattered than the one made by the Superdomes. Another pellet to remove from the list.

At this point in the test, I was starting to lose confidence in the rifle. True, the RS pellets had shown some promise and deserved another chance, but instead I had a thought. What about Crosman Premiers? I normally don’t shoot Premiers in vintage Dianas because I like to use only pure lead pellets, but it sounded like it was worth a try.

The pellets loaded snugly into the breech, but they weren’t quite what I would call tight. The firing behavior, though, was quite different from all the other pellets I’d shot in the gun. It was harsh and a bit buzzy, which tells me the powerplant isn’t being cushioned sufficiently by this pellet.

Down at the target, though, the story was quite different. Premiers made the second-tightest group of the test and were so good that they looked like they warranted a test all their own. The vertical dispersion was 1.09 inches between centers, which is slightly larger than the group made by the JSB RS pellets. The lateral dispersion was only 0.491 inches! And the group was way below the bull, meaning that this pellet dropped many inches from the impact point of all the others. In fact, I’m not certain that all 10 shots landed on the paper because the ragged hole they tore doesn’t tell me how many pellets passed through. It just looks like they all went there.

Diana 25 Crosman Premier target
Crosman Premiers also made a large group, but they were tight side-to-side. This is a pellet to consider further! Sideways dispersion is the gun’s fault. Vertical error is more of an aiming issue or perhaps a wild velocity variation.

Premiers struck the target much lower than the JSB pellets before them, so the feeling upon firing is also evidenced in the velocity. Remember, I’d already adjusted the rear sight higher to compensate for the Superdomes, so this second adjustment jacked it up a lot from where we started.

Observation thus far
The addition of a peep sight to the Winchester 425 was a great idea. It took an accurate and easy-shooting rifle and stretched the useful range many times. I don’t know that a scope would give results that are any better, though it might be fun to try!