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Ammo Testing a Diana model 23 breakbarrel rifle: Part 2

Testing a Diana model 23 breakbarrel rifle: Part 2

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

Part 1


Diana 23
Not as pretty as I would like. This Diana 23 has led a hard life.

Today, I’ll test the Diana model 23 for power. I don’t know what to expect from this airgun, other than not to expect too much. Certainly, the velocity will be low with a powerplant as small as this one.

Cocking effort
I said last time that the 23 looks like a perfect 3/4 replica of a model 27. Well, that extends to the cocking effort, too. Believe it or not, this rifle cocks with just 10 lbs. of effort, making it the easiest-cocking breakbarrel air rifle I’ve ever tested. I don’t know if the mainspring is in good condition, nor do I know what the piston seal looks like; so, it may be premature to say this rifle is representative of all Diana 23s.

The trigger is a direct sear type, with no provisions for adjustment. That’s too bad, because even though it’s two stage and reasonably crisp, stage 2 breaks at 6 lbs., 14 oz. That’s a little high for the best work; and on a rifle this light, it’s very high. It will be hard to use the artillery hold as a result of this heavy trigger.

RWS Hobby
The first pellet I tried was the all-lead, 7-grain RWS Hobby. As light as it is, I’d hoped to see the best velocity figures with this one. Hobbys averaged 381 f.p.s. in this 23. The low was 371, and the high was 401 f.p.s. with a spread of 30 f.p.s. I would have thought they’d go about 50 f.p.s. faster, but I’m still getting used to this gun. At the average velocity, Hobbys produced 2.26 foot-pounds of energy at the muzzle. Talk about your pipsqueak air rifle!

Remember that I did oil the piston seal, which transferred oil to the breech seal, as well. This little rifle should be doing all that it can in its present state.

Crosman Premier lite
Next, I tried the 7.9-grain Crosman Premier pellet. I think this one is on the heavy side for such a small air rifle, but we’ll see. Premier lites left the muzzle at an average 376 f.p.s. Given what the Hobbys did, I thought that was pretty good. The low was 364 and the high was 389 f.p.s., for a spread of 25 f.p.s. At the average muzzle velocity, the energy was 2.48 foot-pounds.

JSB Exact RS
The last pellet I tried was the 7.3-grain JSB Exact RS dome. What a surprise they were! Looking at the velocity of the Premier lites and Hobbys, I guessed these pellets would be in the same neighborhood, but they weren’t. They seemed to fit the bore looser (not loose, but less tight than the other 2 pellets), and the average velocity was 452 f.p.s. That was what I expected from the Hobbys. So, how does a pellet that weighs even more than a Hobby go so much faster? I have to chalk it up to how well they fit the bore.

The low was 449 f.p.s., and the high was 454 f.p.s.; so, the spread was super tight, as well. At the average velocity, this pellet produced 3.31 foot-pounds of muzzle energy — which, while low, is still considerably higher than either of the other 2 pellets. I think this is one pellet I must test in the accuracy report that comes next.

As I mentioned, I’ve oiled the piston seal and breech seal and also rubbed down the entire rifle with Ballistol. I really don’t know the condition of the powerplant, but I suspect that it’s not as bad as the outside would make you believe. And the wood soaked up the Ballistol to shine almost like it did when the gun was new.

What I forgot to do
I’ve already tested this rifle for accuracy, and it turns out we’re going to be interested in the velocity of these pellets seated deep — instead of flush — into the breech. We’re also going to want to test this little rifle at 25 yards, so there’s still time for me to rerun the velocity test.

And then…
After the 25-yard test, I’m thinking of opening up this rifle and seeing the condition of the internal parts. I’m also thinking of stripping all the metal finish and rebluing the gun with Blue Wonder. I think this little rifle will be with us for some time to come.

35 thoughts on “Testing a Diana model 23 breakbarrel rifle: Part 2”

  1. Hello B.B. and Fellow Airguners
    As I was reading the velocity numbers with the JSB Exact 7.33gr. pellets, I was not too surprised with your results. These pellets always give me the best velocity numbers when shot through my guns at under 500 fps. I have come to the same conclusion as you, concerning bore fit. That they are all lead pellets gives them the ability to conform to the lands and grooves of the barrel. I get my tightest groups with the three main .177 JSB pellets. The three I use are, 7.33gr, 7.89gr, and the 8.44. It also helps if you can get them in 4.52mm size.
    I am looking forward to you giving the Diana 23 a new lease on life. Next to shooting, I love to look inside of the gun, and ponder the possibilities. It seems this sport has something to offer a wide range of shooters, and tinkerers.
    Ciao Titus

      • I’d say it’s close to proven…just recently purchased a chrono.
        In my Slavia 630 the Hobby’s and RWS Pistol target are all under the 500FPS limit.
        The 7.3gr Exacts are running about 510.

    • Titus, remind me of the bow weight you used for your competition shooting. Was it 70 yards? I seem to recall that the bow weight was 40 pounds. Is that right?


      • Hi Matt61
        First, let me say how much I enjoy reading your anecdotes about your trials and tribulations with guns and shooting ranges. Do I recall correctly that you have penned a book? If so,I would certainly like to give it a read. You have a real gift concerning the use of the English language, my friend.
        When it came to competition, I felt the most comfortable using 50-52 lbs.@ 50% let-off. This combination gave me the best groups at the furthest distances such as 90 and 70 meters. I tried moving up to 60 lbs @40% let-off, however half way through a FITA tournament (144 arrows-6 sighters), I was really bagged. I often encountered people using a heavier weight with 60-75% let-off. This never worked for me. When I tried a 60% let-off, I found it was like aiming with a 4lb. gun. I had a hard time keeping steady while aiming. I needed more tension when holding at full draw. There was so much trial and error involved in getting the right combination. I would often spend 5-8 hr. at the range, 6 days a week. It had to be a labour of love. I was also fortunate in having the unlimited use of a lathe. I made wheels of differing sizes, and let-off rates, out of deloran, or aluminum. The wheels I didn’t use, I always tried to gift to another archer. A lot of lessons I learned in archery, I have also used in shooting airguns. Things like relaxing, follow through, sight picture, etc, seem to be universal in the shooting sports. Because you are involved in two distinct shooting disciplines, archery, and guns, does not mean techniques learned in either sport, cannot be transferred both way. Lessons learned from one, can and should be used when dealing with the other.
        Ciao Titus

  2. B.B.

    Would be a good idea to check out the Main Spring & Piston Seal. This gun is capable of a bit more with a new spring and piston seal. Should be able to do around 600 fps I would guess. We shot down crows with ease at around 20 meters (dead before they hit the ground every time). Hope you would try it out as I think it would be worth it.


    • I bet you had good shot placement to take those crows with such low power. Good shooting!
      B.B. had a blog years ago about making leather seals and I followed the procedure and made a new leather cup seal for a cheap, tired B3. I remember being amazed at the improvement it made.

      • Lloyd

        It was easy really. They used to sit on the roof of an old house next door & we rested the gun on a pillow against the window sill!About the new leather seal yes its amazing how it boosts power instantly.


      • B.B.

        I know you will do a fantastic job on it Sir. Just wanted to share my experience of this gun with you. I can’t wait to check out the performance when its done.Best of luck!


  3. B.B.

    I forgot to mention that the hole in the leather breech seal that is also the air transfer port should be just the right size to get optimum power. We went through quite a few to get it right, about 2 mm diameter.


  4. BB
    That would be a good blog to do.
    Restoring a air gun/refinishing the wood and re-bluing the metal.

    When my dad made his guitars he said when you held it in your hands you new you got the finish right when the guitar felt like silk touching your skin. And he would order the prettiest grain wood that I ever seen. On a guitar or gun for that fact. I now wonder how much he had to pay for that wood.

    • Memories and lessons like that really hold a special spot in our lives. You are fortunate.
      You and J-F both mentioned the pistol butt stock adapter yesterday. The full adjustability makes it easy to get a good cheek weld with the eye falling right in line with the scope every time. And no big chunks of wood and bunches of rods to deal with.

      • lloyd
        I’m a big fan of the Benjamin Marauder pistol. And I got a few of the Crosman pistols/1720T, a 2240 with a Disco barrel and breach and a 1377 with the same .177 Disco barrel and breach. I got the 1399 Crosman stock on them all.

        So yes seeing the AR stock adapter for the pistols excites me. Now I see that I got more money saving to do again. Would definitely like to try one of them on one of my pistols to see how they feel though.
        But I bet after getting one I will want to do the other ones just to give them that custom look also.

        Yep I like them.

  5. B.B.,

    My guess is a tired mainspring. I have a Gecado-branded 23 and it generates around 4 foot-pounds muzzle energy. I got just under 500 fps with Hobbies and about 460 fps with Premier Lites. The velocities for your 23 are in the ballpark for a Diana model 16.

    Paul in Liberty County

  6. BB,
    I do hope you open this rifle so we can all see the condition she’s in. Perhaps the seals or mainspring will be something you’ll tweak and continue this great blog series.
    Chris S.

  7. Big day is coming up. I’m gearing up for deer hunting. The Mossberg 100ATR is getting cleaned, oiled and ready to punch a hole in the universe, camo is all being cleaned and descented and I have gathered my intel on what is where and when. Got my license today and there is an energy in my place equal to getting ready to drop into a combat zone via Blackhawk. Those were exciting times. They are long gone but that doesn’t mean I can’t get that same energy with prepping for deer hunting. I’m hoping for a nice sized buck that has eluded me for a few years. We shall see who my next victim is. I’m hoping I’ll be able to take a trophy as well as a freezer full of meat.

  8. I just saw on facebook that PyramydAir was moving to a new (bigger I guess) location again.
    I think it might be time for a new tour/report on the PA warehouse and offices.
    I can’t talk for the others but I always enjoy a look behind the scene.


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