Part 1: Triggers

History of airguns

This report covers:

  • Background
  • Big difference
  • Not the only difference
  • Triggers
  • Other differences?
  • BB learned, too

This report is my second attempt to answer reader Roamin Greco’s question about the difference between the Diana 35 and 45. After I published the first report on their triggers I received this comment from Roamin, “Thank you, again, B.B. My question was a bit more general. Are there other differences like tube diameter or piston stroke, in addition to the trigger adjustments that would really allow a buyer to compare and contrast the two guns?

They both seem to be full-sized rifles. I was a bit surprised when I got my Winchester 435. It was bigger than I imagined, even after reading your previous reports on the 35. But I really like it and I look forward to replacing the spring (or at least removing any broken pieces) It may crunch a bit when cocking, but it is a really easy cocking gun right now and a pleasure to shoot offhand. And best of all, it turns out to be not pellet picky at all!”

Background

To answer this question I first need to explain that there are, in fact, two Diana 35s. One is older and slightly smaller and easier to cock. No doubt the barreled actions are the same but the older version’s stock is slimmer and sleeker. I reported on that one in 2019. I bought that one from reader Carel in the Netherlands and it is the first of its type that I had ever seen. Until that time I thought all 35s were like the Winchester 435 that Roamin Greco describes.

I have also owned at least one of the newer versions of the Diana 35 that’s like Roamin’s Winchester 435. I described it in 2008 as a powerhouse in its day but weak by the end of its life.

old Diana 35
The older version of the Diana isn’t so much smaller as it is slimmer.

Winchester 435
The later Diana 35, like this Winchester 435, has a larger, thicker stock.

Here is what I said in 2008, “When the design was new in 1953, the 11 foot-pounds it generated in .22 caliber was considered stupendous, but by 1977 it had become mediocre. Rifles like the BSF 55 and the Diana 45 had longer-stroke pistons that were capable of much higher velocities, and the long-stroke FWB 124 that started it all, of course, was one of the most potentially powerful spring guns of the era. Unfortunately for Diana, nothing could be done to remedy the situation, so in the late 1980s, it faded away – replaced by the models 34, 36 and 38 that came out in 1984. These long-stroke spring guns represented modern technology at its best, taking velocity in .177 caliber up to 1,000 f.p.s., where guns like the 35 could no longer compete.”

Over thirty years have passed since the Diana 35 left the world stage, and the airgun world is now in a renaissance period. Lower-powered spring guns are once again embraced. The Diana 35 is a larger, more adult version of the extremely popular Diana model 27, and many now find it to be an appealing spring rifle to add to their collections. If the spring twang is eliminated and the trigger is tuned to break crisply, the 35 becomes a classic airgun – the kind everyone wishes they still made. If you can ignore the chronograph, the Diana 35 can be a wonderful companion. Viewed that way, instead of as the powerful spring gun it tried to be, you can be very content with this fine old classic.”

Big difference

If you read that quote you caught the major significant difference between the 35 and 45 — the length of the piston stroke. It’s not the only difference, but it’s one of the two big ones.

Roamin asked me about the diameter of the pistons of both air rifles. The model 35 piston is 21mm in diameter. The model 45 piston has a 21 mm piston as well. So, what’s the deal? Why is the 45 more powerful (right at 800 f.p.s. with light .177 pellets, while the 35 is in the mid to high 600s)?

The deal is swept volume and the 45’s longer piston stroke gives it the edge. But here is the real deal — I think. A longer piston stroke does more to boost power than a larger piston diameter. Yes, both will increase the swept volume, but the longer stroke increases the amount of compression, while the larger diameter piston only increases the volume of air that is compressed. In spring-piston guns I believe it is the pressure that boosts velocity more than air volume. I say that for a good reason. We have gotten to the limits of both piston size and stroke length. The Beeman R1/Weihrauch HW 80 have 30 mm pistons. But their piston strokes are not maxed out. On the other hand we see lots of Spanish, Turkish and Chinese breakbarrels whose strokes are about as long as can be. And those rifles exceed the former ones by several hundred f.p.s.

And you can add mainsprings to the discussion. Stronger mainsprings do very little to add power to a spring gun. I have been saying that for 28 years but people still think the spring is the thing.

Yogi, this is why we see so many breakbarrels with their barrels broken open so far. It’s also how Diana got their sidelevers to shoot so fast with a sliding compression chamber that reduces the diameter of the piston. The Diana 48 and 52, for instance have 28 mm pistons yet they surpass the R1/HW 80 whose pistons are 30 mm.

Not the only difference

Roamin, there is more and I showed it to you in the report I did on the rebuild of the Diana 45. Diana put a sheet metal sleeve inside the piston to tighten the clearance between the mainspring and the piston body in an attempt to reduce vibration, among other things. The “other things” I think are to keep more lubrication on the mainspring. Either they didn’t have Almagard 3752 (Tune in a Tube) or Red N Sticky grease in those days (the late 1970s through the ’80s) or they didn’t know about it.

Diana 45 piston sleeve outside piston
The Diana 45 has a sheet metal liner inside the piston to tighten the tolerances.

Unfortunately the Diana 45 was a notorious buzzer. And the 35 could be, as well. But we have TIAT, so we don’t have to put up with it.

Triggers

I have already addressed the differences in the triggers of both rifles and that is another major difference. The ball bearing trigger of the 35 is certainly complex, but Diana didn’t go the simple route for the 45 trigger. It’s complex, too. The principal difference is that the 45 trigger is modular while the 35 trigger is a set of parts that must be inside the gun to be held together. Outside the gun that trigger is just parts.

Modular triggers were the future for Diana. We now see the T06, which is the 6th iteration (?) of a modular trigger. When engineers design a new air rifle of a certain price range (and coiled steel mainspring) they design around the envelope of that trigger. Yes, that does limit the design possibilities somewhat, but if it works why change it?

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Other differences?

No doubt there are other differences between the 35 and the 45, but they are minor and probably relate to the two big differences we just discussed. Roamin Greco, I hope that clears it up for you.

BB learned, too

In these two reports BB has done some considerin’. His new/old 45 cocks at 39 pounds which is way too much for the velocity it’s putting out (an average of 681 with Hobbys). I don’t need velocity. What I need is smooth shooting and lighter cocking. And I’m gonna get it! So, Roamin Greco, you influenced BB Pelletier — the Great Enabler! Good on you, mate!