Diana 25 smoothbore pellet gun: Part 5

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

Part 1
Part 2
Part 3
Part 4

Diana 25 smoothbore
This Diana 25 smoothbore was made in World War II.

Today’s blog falls under the heading, “It’s not always a good idea to try everything.” Back when we were exploring the Diana 25 smoothbore airgun, we saw how incredibly accurate it was with certain pellets at 10 meters.

Diana 25 smoothbore JSB Exact RS deep-seated group
This 10-shot group of JSB Exact RS pellets was shot at 10 meters. The extreme spread measures just 0.337 inches between centers! It made us all wonder just how accurate a smoothbore pellet gun can be.

When I backed up to 25 yards, however, the groups opened up to between 2.5 and 3+ inches for the same pellet. Obviously, the pellet needs to be stabilized by both the high drag of its diabolo shape and by the spin introduced by rifling. Drag, alone, is not enough to stabilize the pellet.

One reader then asked me to try shooting round lead balls in the gun. Today, I’ll conduct that test for you.

Beeman Perfect Rounds
I shot Beeman Perfect Rounds, which are H&N Rundkugel but under the Beeman label. They weigh 7.7 grains, which is the weight of a medium-weight diabolo pellet.

The balls fit the Diana’s breech quite well, though one was slightly larger than the others. But the rest would not drop into the breech and had to be seated with the thumb — just as a pellet would. They did seat easily, however, and I noticed the gun’s powerplant seemed harsher than it is with pellets. I suspect the balls had less resistance than a pellet since they only touched the bore at their circumference, and there’s no rifling to engrave them.

Diana 25 smoothbore pellet gun round ball in breech
Except for one, each round ball fit the gun’s breech very well. Most stopped like this and had to be gently pressed into the bore with the thumb.

Testing at 10 meters
I began the test at 10 meters, thinking the gun was accurate at that distance with diabolos, so it should be accurate with round balls. I’m sure the reader who asked me to test round balls must have thought the same thing. But when I fired the first shot and could not find the hole on the target paper, I stopped shooting. Fortunately there were no new holes in the wall!

I then moved up to 12 feet and shot again — this time standing and using the door jamb as a brace. The shots now went to the bull at which I was aiming. But the group is hardly worth celebrating. Ten shots went into 1.166 inches at this distance. I’ve shot many BB guns that could do so much better than this that it’s embarrassing to consider.

Diana 25 smoothbore pellet gun 12 foot group round balls
Ten shots from 12 feet did make a group on the target, but that’s way too close for a gun like this! Group measures 1.166 inches between centers.

I guess the Diana 25 isn’t made to shoot round balls. If there was any doubt before, I hope this clears it up. I didn’t shoot any more groups because of how harsh the powerplant seemed to be. I didn’t see any reason to strees the mechanism more than I already had.

Darts?
Shooting round balls got me thinking about other types of non-pellet projectiles, and of course darts came to mind. I decided not to try them in this gun,as the powerplant is too powerful for them. It would bury a dart deep in wood, causing its destruction upon extraction. But that did give me another idea.

I was recently asked to conduct a retest of a gun I tested some time ago. Apparently, a blog reader felt my results were not typical of the gun I tested, so he called the manufacturer and they contacted me. That gun in question is a smoothbore, as well, and it’s a multi-pump, so the velocity can be controlled. I plan on testing darts when I test that gun for you.

28 Responses to “Diana 25 smoothbore pellet gun: Part 5”

  • Herb Says:

    BB,

    Your test demonstrates why British clubs in 1900′s-1910′s switched to diabolo pellets instead of round balls.

    Regards,
    Herb

  • J. Says:

    BB,

    Which multi-pump are you retesting? The Daisy 35?

    J.

    • B.B. Pelletier Says:

      J.,

      Yes, the Daisy model 35. It will be tomorrow’s test. Look for some surprises!

      B.B.

      • J. Says:

        BB,

        Cool beans! Its no surprise after the comments I made on some of the posts about the Diana 25 that I thought the test on the Daisy 35 didn’t use enough pellets. However I never expected anyone to complain to the company to get you to retest it.

        I’m looking forward to seeing the results you got this time.

        J.

        • B.B. Pelletier Says:

          J.

          It will be worth the read! A very interesting test.

          B.B.

          • jon Says:

            Oh, oh. I’m the guilty one Tom. Here is how it went down. I had decided that I would like a smooth bore BB and pellet shooter, so that I might be able to shoot BBs without having to worry about doing damage to the rifling. Somehow I got interested in the Daisy Model 35. I read the reviews at Amazon and at Pyramidair.com, and they actually were quite good. The gun got quite a few 5 stars even for accuracy. Then I found your 3 part review and read it all. Of course your test gun was a terrible shooter. I consider you to be one of the best air gunners in shooting ability, general knowledge, and working on air guns. I wrote a message to you here at your blog, that your Model 35 must have been a lemon. You replied that, it may be, but you have to test them as you receive them. You wrote it up as you should have being honest to your readers. Then I read this thread on the GTA forum:

            http://www.gatewaytoairguns.org/GTA/index.php?topic=42173.new;topicseen#new

            I decided to order a new Model 35 and take a chance on it. When I got it, I had no scope to put on it, so I had to shoot it with open sights, and I’m 59 with bad eyesight. Even so, at 10 yards from a rest, and I was using 3 pumps as my Remington Airmaster can be a tack driver with 3, I got some literally one hole tiny 3 shot groups while testing pellets. And I got them with Crosman Premier wadcutters and hollow points, Gamo Match wadcutters, and a few with Crosman Destroyers and Hunters. My favorite RWS Hobbys didn’t do so well. And my bad groups were still mostly respectable. I decided that my eyesight was holding this gun back, and that I got these 0.0″ center to center groups with the open sights, that the gun deserved a scope. I didn’t want to spend much, so I got a Tasco 3x7x20mm scope for like $16.50. Well with this low end scope the results are that my percentage of really good groups went up. I’ve onbly tried a few groups with BBs, and got about 3/8″ center to center. Yesterday, I moved my target back to 20 yards, and tried a few of the guns favorite pellets to see how accuracy would degrade. I got groups of about 1/2″, 3/4″, and 5/8″. Nothing to write home about, but not bad for a smooth bore.
            During all this at some point, I went to Daisy’s website and left them a message asking them if they were aware of how badly the Model 35 test gun did in your review. I told them about how mine was shooting and that I was sure your test gun was a lemon. Believe me, if my gun shot like your test rifle, I would have boxed it up and sent it back.

            So, that’s the story. I am shooting my Model 35 almost every day. I love how quiet it is, and it handles well and shoots good. I just started thinking about, if I worked for Daisy, and one of our guns made it out of the factory shooting like your test gun, I would darn sure want to know about it. The gent from Daisy answered my message and said he would like to get that gun back to check out why it was so inaccurate.

            So, it was me that must have got the whole thing rolling. Hope you aren’t mad at me, as I read your blog every day, and even read through your older entries here, as it’s a treasure trove on air gun information. My Model 35 is a good shooter for like $35 plus the scope. Can’t wait to read your follow up test. Hope they sent you another gun though.

            Jon Neet (birdmove at most forums)
            Keaau, Hawaii

            • B.B. Pelletier Says:

              Jon,

              No, I’m not mad. It’s people like you who really care about their airguns, that are helping this sport to grow.

              I normally don’t like to revisit the same gun, just to test it with other pellets, because it usually doesn’t turn out well. If I did it regularly, every airgun maker would be after me for a retest when their guns did poorly in their eyes. But this time it was different.

              The Daisy model 35v is a smoothbore, and my recent testing of the Diana 25 smoothbore showed me some things I hadn’t known about smoothbore before. So when Joe Murfin called me, I was happy to accommodate him on this retest. And seeing how it turned out, I’m glad that I did!

              Thanks,

              B.B.

  • goatboy Says:

    What an awesome idea about darts, i have simply forgotten about them since i lost my old Webley pistol years back. I have an old Mod 16 with a worn spring which the wife has claimed as hers, i think I’ll get her a pack next time i load up on pellets. If I’m lucky she might let me use it again, but she has grown rather fond of it and says i can stick with my big heavy full power air rifles. So hands off! Bless her.

    TTFN

    Best Wishes, Wing Commander Sir Nigel Tetlington-Smythe

    • B.B. Pelletier Says:

      Sir Nigel,

      I spoke too soon. The gun I am testing is a Daisy model 35 that has a breech too small to load a dart. Oh, well. :(

      B.B.

      • J. Says:

        BB,

        Are you using the feathered darts or the ones with the stiff plastic vanes? (Do they even still make the ones with the stiff plastic vanes?) The reason I ask is that the ones with the stiff plastic vanes could probably be muzzle loaded if you really wanted to test them in the Daisy 35.

        J

        • B.B. Pelletier Says:

          J.,

          I was planning on using the darts that have tufted fabric fletching, like a pipe cleaner.

          Muzzle-loading, you say! Well, I have time to try that today and change what I said about the 35 not shooting darts, it it turns out to work.

          Thanks,

          B.B.

      • Matt61 Says:

        I didn’t see much of a future for darts. I was appalled at how easy it was to destroy my expensive arrows at about $5 each. My marksmanship was not helping. Fire and forget is the way to go.

        Matt61

  • Mike Says:

    i remember trying darts in my Marksman pistol years ago. It didn’t have enough power for them. They also were very inaccurate.

    Mike

    • J-F Says:

      Ah! but was it the darts or the pistols fault ?
      I still have 2 or 3 of those, last time I tried one the pellet barely made it out the very short barrel.
      I don’t remember who but someone tried to accurized one with a Daisy 499 tube. It was better but it was no target pistol.

      J-F

  • hankmcrae Says:

    B.B.,
    Great photo of the round ball in the breech. The detail is amazing.
    It might be an illusion, but it looks like the breech seal has a bit missing. In the previous accuracy test flush seating JSB Exact RS pellets shot a very vertical group, then deep seating saved the day. Could deep seating a pellet put less stress on a breech seal?
    -h

  • Bradly Says:

    If I remember correctly, the darts with feathers were for smooth bore and the darts with the hard plastic vanes were for rifled barrels…or so I’ve read

    • J. Says:

      Bradley,

      Yep. That’s correct. They ones with the hard plastic vanes were “supposed” to be used with a rifled barrel. That doesn’t mean you couldn’t shoot them in a smoothbore though. ;)

      For what its worth… I’m not even sure how easy it would be to load the darts with the hard plastic vanes in a modern multi-pump from the breech. It seems to me the breech area is a lot smaller on the modern ones than it was on the old Crosman 664 I used back in the mid 90s.

      J.

  • /Dave Says:

    BB,

    Your breach seal looks pretty torn up in the photo. I don’t know the gun, so I don’t know if that’s a seal that you can just flip or not, but it definitely looks like something you might want to fix.

    /Dave

    • B.B. Pelletier Says:

      /Dave,

      Yes, it does look tired. Seals like that are made from leather belts, and I can certainly make one.

      B.B.

  • Matt61 Says:

    Mike, you must have a giant supply of ammo to be willing to sell in these troubled times.

    Matt61

    • Mike Says:

      I have a fair amount but I also have some that I no longer have guns to shoot it in. Ammo like the 8 mm Mauser I told you about. I also have some 41 Magnum and 6.5 Swedish Mauser I bought at an estate sale at a very good price. I may even sell a few boxes of .22 LR! (But not much!). The .22 ammo will attract folks to my table (It’s called a Leader).

      Mike

  • Mike Says:

    I recently inherited a Diana 23 (Millbro) and it is in serious need of refurbishing. From what I can remember, it was never in assembled condition in my lifetime (30+years). My questions are, how do I compress the spring while inserting and mounting the trigger housing? What is the best finish to apply, and how to best clean and prepare the metal surfaces for refinishing? Is Chambers in England the best source for parts for this gun?

    • B.B. Pelletier Says:

      Mike,

      If you live in the UK, Chamers must be a fine place to shop. I wouldn’t know.

      As for compressing the mainspring, you can probably do it without a compressor, but that is only if you know what you are doing. Because you don’t, and probably want time to figure things out, I recommend you build a mainspring compressor.

      Here are some reports to look at:

      http://www.pyramydair.com/blog/2006/07/spring-gun-tuning-part-2building.html

      http://airguns.itgo.com/custom2.html

      For tuning tips, I suggest you read all 13 parts of this report:

      http://www.pyramydair.com/blog/2006/08/spring-gun-tune-part-13-range-testing.html

      B.B.

    • CCserX Says:

      Your [milbro]mod.23 is the rarest junior gun made by the millard bros;motherwell,scotland concern (operating 1946-1982)-;it,s a solid-barrel improvement in the semi-tinplate [diana]mod.22 of 1926(germANY) and final emanation of this petite airgun was the mod.G76 “PERFECTA” of the late seventies aimed at the german market. [Milbro] was set-up using war-reparations machinery representing the [dianawerk]production -line also the [moritz und gerstenberger] “zenit” hebelspanner airpistol became the [milbro] mk.IV.Because they carried the “huntress”trademark the scottish airguns were also known as the “british diana” while back in germany the mayer&grammelspacher concern were forced to call themselves “original” until [milbro] folded and at that juncture an “oompah” band came over to escort the trademark homeward! A spring that fit this airgun is the [weihrauch]mod.hw45 airpistol one.regaRDS CCserX

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