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Education / Training Diana 45: Part 3

Diana 45: Part 3

Diana 45
A late Diana 45 from RWS.

Part 1
Part 2

History of airguns

This report covers:

  • The test
  • Sights
  • First group — Hobbys
  • Trigger
  • H&N Baracuda with 4.50 mm heads
  • Baracuda group 2
  • Norma Golden Trophy FT
  • JSB Exact RS
  • Shot cycle
  • Summary

Today I start testing the accuracy of my new/old Diana 45 that I bought (or traded for) at the airgun show in Malvern, Arkansas, last year. Today’s test was strange, and you’ll soon know why.

The test

I shot from 10 meters off a sandbag rest, using the artillery hold. The 45 moves a lot when it fires and I’m pretty sure the artillery hold is the right way to go, but next time I will test the rifle rested directly on the bag as well. In fact I adjusted my hold as the test progressed and I’ll mention that when we get there. I began shooting with the rear of the cocking slot resting on my off hand.

Yes, there will be a second 10-meter accuracy test because of that strangeness I mentioned. I want to test this rifle with more pellets before doing anything else.

I shot 5-shot groups today because this wasn’t supposed to be a test of the rifle’s accuracy — just a test of the pellets it likes. Famous last words!


In part Two I mentioned that reader Mike Melick from Flying Dragon Air Rifles had gifted me with a Chinese-made replacement front sight for this rifle. It is actually made stronger and I think better than the German original, and it held tight to the barrel throughout today’s test. It has a tapered post insert that I used for today’s test.

First group — Hobbys

Since I’m sighting with open sights I expected to be on paper with the first shot, so I started at 10 meters. I first shot two pellets to “warm up” the powerplant. Some springers need that and others don’t. I was pleased to see the first two shots go exactly where I aimed from 10-meters away.

The first official RWS Hobby pellet, which was the third one fired, nicked the 9-ring of the 10-meter rifle target, so I left everything where it was and shot another 4 times. As you will see the other 4 pellets went to the left and landed in a vertical string. I don’t think this rifle likes Hobbys. This first group measures 0.96-inches between centers — almost a one-inch group. That’s no good.

Diana 45 Hobby group
The Diana 45 put five RWS Hobby pellets into a 0.96-inch group at 10 meters. I think it’s obvious the rifle doesn’t like this pellet.


As I mentioned in Part 2, the trigger is two-stage and very nice. I didn’t start feeling stage two until the fourth shot of this string, which is 6 shots from the start. I then felt it off and on for the next 10 shots or so. After that I felt it every time. I think that’s a combination of the trigger needing to be warmed up through use and BB needing to remember how to squeeze it. Once that second stage kicks in this trigger is marvelous!

Stock Up on Shooting Gear

H&N Baracuda with 4.50 mm heads

The next pellet I tested was the H&N Baracuda with a 4.50 mm head. This is where the fun began because my first shot with no sight adjustment and the same artillery hold hit the paper 2-1/2-inches below the aim point. It took me a long time to even find it through my Meopta binoculars. So I now have to sight in my rifle.

Huh? I’m sighting in on the SECOND target of the test? I told you this was a strange report!

I cranked the rear sight up a bunch of clicks (too many to count) and fired again. The second shot rose 1-1/2-inches and went a little to the right, though I called that pull to the right. So, more up elevation until the rear sight started floating, and I had to go down a couple clicks again to put the spring under tension. The Baracudas landed just below the bullseye at which they were aimed.

Then I shot five times and got a group that measures 0.438-inches between centers. That’s looking much better, but the strange things were not over. Two pellets later I shot a different pellet at the bullseye below this target and those shots climbed up alongside this group. Fortunately I had spent some time looking at this group and was able to tell which pellets belonged and which did not. I drew a line around the pellets in this Baracuda group.

Diana 45 Baracuda group 1
I drew a line around the group of five Baracuda pellets. They measure 0.438-inches between centers and are fortunately separate from the pellets that hit next to them. This is the smallest group of the test.

Baracuda group 2

Because of the tightness of the first Baracuda group I shot a second group at a different target. I did adjust the rear sight two clicks to the right for reasons that escape me now when looking at the result. These five are within 0.594-inches, center-to-center.

Diana 45 Baracuda group 2
The second group of Baracudas is sized 0.594 inches between centers.

Norma Golden Trophy FT

Next I shot 5 Norma Golden Trophy FT pellets. They landed in a 1.09-inch group. It is the largest group of the test. I was told these Norma pellets are very much like  RWS pellets, so, like Hobbys, these are pellets to avoid in this rifle.

Diana 45 Norma Golden Trophy group
Five Norma Golden Trophy pellets made this 1.09-inch group at 10 meters. It is the largest group of the test.

After this group I slid the rifle back so my off hand was at the end of the cocking slot. The rifle seemed more stable this way.

JSB Exact RS

Next I shot five JSB Exact RS pellets. These are the pellets that hit the target 2-1/2-inches above the aim point and landed right next to the Baracuda pellets you saw earlier. I did not draw a circle around this group that measures 0.462-inches between centers.

Diana 45JSB RS group 1
This group is the one outside of the line. It is five JSB Exact RS pellets in 0.462-inches.

That group was so nice that I shot a second group with the same pellet, after adjusting the rear sight three clicks to the left and eight clicks down. This time five pellets hit the target I aimed at and went into 0.637-inches at 10 meters.

Diana 45 JSB RS group 2
Five JSB Exact RS pellets went into 0.637-inches at 10 meters.

Shot cycle

Because I was using the artillery hold I felt the rifle pulse with every shot, but I didn’t feel any vibration. I could hear it, but not feel it.

This 45 is roughly equivalent in accuracy to the other 45 I tuned. I would like to quiet the mechanism, but nothing will stop the movement of the rifle when it fires.


I now have a good idea of how accurate  this rifle is I think I will tune it before proceeding with more accuracy testing. I won’t button the piston like I did with the other rifle. I’ll let Tune in a Tube do its job and I think I may replace the mainspring. We shall see.

author avatar
B.B. Pelletier
Tom Gaylord is known as The Godfather of Airguns™ and has been an airgunner for over a half-century, but it was the Beeman company in the 1970s that awoke a serious interest in airguns. Until then, all he knew were the inexpensive American airguns. Through the pages of the Beeman catalog, he learned about adult airguns for the first time. In 1994, Tom started The Airgun Letter with his wife, Edith. This monthly newsletter was designed to bring serious reports about airguns to the American public. The newsletter and Airgun Revue, a sister magazine about collectible airguns, was published from 1994 until 2002, when Tom started Airgun Illustrated -- the first American newsstand magazine about airguns. Tom worked for three years as technical director at AirForce Airguns, the makers of the Talon, Condor, and Escape precharged air rifles. Today, he writes about airguns and firearms for various publications and websites. He also makes videos, and you'll find short clips embedded in some of his artices on Pyramyd AIR's website. Tom is a consultant to Pyramyd AIR and writes under the name of B.B. Pelletier.

25 thoughts on “Diana 45: Part 3”

  1. BB,

    Why do you feel that you have to replace the mainspring of this rifle? You didn’t mention anything hinting that the spring might be canted or broken. Seems to be a hold sensitive rifle.


  2. BB,

    I personally like tapered and perlkorn front sights. The perlkorn on the 1906 BSA is shaped like a tear drop with the point upward. For rear notched sights, I like a V rather than a squared off notch. The V helps to center the front sight and the taper or perlkorn helps to make the aimpoint obvious.

    I have never liked the squared off front sight and rear notch. There is too much inherent error, most especially when you push out to 25 yards or so. I guess they work pretty good for combat pistols, as they are easier to find and line up, but…

    I do prefer a rear aperture sight though. They are so easy to use. Do you have one that will fit that Diana rail?

  3. B.B., in your prior report, Superdomes gave you the smallest velocity spread, but you didn’t test them for accurracy. Otherwise, this is not a very auspicious performance. I look forward to seeing what you can do to improve her.

  4. I love these old girls. Such a classic rifle. In other news: PA reached out to me and discussed my issues with Dragonfly 2. They immediately offered a replacement or refund and sent me a prepaid return label. They flagged my return for testing/inspection to see what went wrong with it as it seems my experience is quite the aberration. They are even throwing in a free 10 shot test to make sure my replacement is a good one. I just love the customer service I get from them.

  5. BB
    After having survived a week of So Cal blistering heat in a drought, turning 75 and having to evacuate for Border Fire 32 where the fire department cut open an unlocked gate and now going through 60mph winds with Hurricane Kay without much more damage than a few missing garage roof shingles, I celebrated the cool night air tonight with a few MGD’s.
    I realize this is not a new airgun and optimizing its performance will be somewhat of a challenge. But it reinforces my belief that airgun manufactures should make it clear that at the time of manufacture the airgun at hand will perform the best “With the following Pellets” . If not at least issue a statement that “This airgun has no guarantee of accuracy and needs to be shot with every pellet known to mankind to determine which one will perform the best in each and every shooting category “. “Caveat Emptor”

    • Bob M,

      LOL! If the marketeers were to tell the truth, they would not sell ANY airguns and would be immediately fired. Very, very few airguns, if any, come with a recommendation of which pellet to use, much less one for accuracy. If one should recommend a pellet, it will be of the same brand as the airgun, increasing that company’s profit with another sale.

      • RR
        Good point. Airgun manufacturers could rebrand pellets that work well in their specific airguns. Everybody wins.
        If I remember correctly FX made it clear they designed the smooth twist barrel around a certain well known pellet and recommended it for use. Thumbs up for FX.

  6. Well, today I tried unsuccessfully to replace the sear in my Webley Junior. It would not work. On close examination it turns out the new sear is different than the old sear. Now I am going to have to do some filing and rehardening. Yeah.

  7. BB,

    I have to admit that I am just a little bit confused. If the spring was broken as many Diana springs end up being, I could understand the lower velocities, but would that not lower the cocking effort also? I could also see where too much grease in the action can slow the shot cycle down, but your picture of the spring through the slot does not appear to be overly lubricated.

    It will be quite interesting to see just what is causing such a high cocking effort and low pellet velocity. Could it be due to a leaky breech seal or a bad leather piston seal?

    Funny thing, that. When I think about it, most of my sproingers have leather piston seals. I know there are kits out there to replace these seals with modern synthetic seals. Maybe, since you are planning on tearing this one down, perhaps you could get one of these kits to fit this 45 and see if it makes a real difference when compared to the leather seal?

    • RidgeRunner,

      Looking at the force required to cock it and the relatively low power despite the effort exerted I think we may find that the spring is longer than it needs to be bordering on coil bind with excessive preload. Tom might experiment with spring cutting to the minimum preload with the current spring before replacing it with a new one.


      • Siraniko,

        I would, but I seriously doubt BB will. He is more likely to contact someone and have them send the correct spring.

        There is some reason for the high cocking effort and low power output. I impatiently await his internal inspection.

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