Diana model 26 breakbarrel air rifle: Part 2

by Tom Gaylord
Writing as B.B. Pelletier

Diana 26
The Diana 26 air rifle.

Part 1

A history of airguns

This report covers:

  • This is a .177
  • RWS Superdome
  • Firing behavior
  • Trigger pull
  • No vibration
  • JSB Exact RS
  • Hobby
  • Barrel tension
  • H&N Baracuda Match with 4.50mm heads
  • Sig Match Ballistic Alloy
  • Discussion
  • Cocking effort
  • Summary

I asked in Part 1 for owners of Diana 26s to tell me of their airguns and I was surprised that so many responded. Apparently I was in the minority for not knowing about the Diana 26. From what they said and what I’ve read I have learned that the 26 was closely related to the model 28 that came out when the model 27 ended production. So models 23, 25, 27 and 35 went away and models 24, 26, 28 and 34 came into being.

The model 34 is a whole story on its own, that I will cover one day, but not today. This report came about because I wanted to get a model 35, to see if I could tune it to be as smooth and light-cocking as a 27 and have a little more power. I got the 35, which is an early rifle with some very curious features, but I also acquired this model 26 and a model 27S that’s equally unusual. We are looking at the 26 in this series, so that’s where the focus will remain today.

Today we will look at power. Carel, the man I bought this rifle from, had installed a Maccari mainspring, so the powerplant on this rifle is not stock. It shoots very smooth, and I’m inclined not to mess with it — other than to test it and see what it can do. I am curious how it stacks up against a Diana 27.

I’ll also report on the feeling when the rifle fires, the velocity, trigger pull and cocking effort. Let’s get started.

This is a .177

As much as I have reported on vintage Diana air rifles, I haven’t done much with .177s. I have owned, tuned and tested them, but they never interested me like the .22s. Maybe I thought the .22s are smoother — I don’t know the reasons. I just know that when it come to a .177 Diana, I’m uncertain. This will be a learning experience for me, just as it is for many of you!

I did lube tune and test a .177 model 27 back in 2008-2009. That rifle was way off it’s power when I got it, but my tune brought it back strong. I will include some comparison data from that tune in today’s report.

RWS Superdome

Dianas do well with RWS pellets, so the first pellet I tested was the RWS Superdome. This 8.3-grain domed pellet is on the heavy side for a gun of this power, which I assume is around the 650 f.p.s. range with lightweight pellets.

Superdomes averaged 566 f.p.s. in the 26, with a spread of 27 f.p.s. The low was 546 and the high was 573 f.p.s. At the average velocity this pellet produced 5.91 foot-pounds of energy at the muzzle.

For comparison, the Diana 27 that I tuned in 2009 shot RWS Superdomes at an average 563 f.p.s. with a 24 f.p.s. spread. The low was 552 and the high was 576 f.p.s. That’s pretty similar.

Firing behavior

This 26 shoots like a tuned spring-piston rifle. The cocking, for starters, is very precise. A regular vintage Diana will cock and then the barrel will come back a bit after the sear catches; this one goes all the way to the end before the sear engages and then it stays there. By that I mean the barrel doesn’t bounce back an inch or more. There is very little slop in this rifle. The mainspring feels like it is coil-bound at the end of the cocking stroke, which is typical of Maccari tunes.

Trigger pull

The trigger is set about as perfectly as it can be. It’s a crisp 2-stage pull and stage two breaks like the proverbial glass rod. Stage one of the pull is 1 lb. 11 oz. and stage two breaks at 2 lbs. 13 oz. I told you that I wasn’t sure if this rifle has the ball bearing sear or some other arrangement. Perhaps Carel will tell us. Some 26s have ball bearing sears and others don’t.

No vibration

There is no vibration on the shot. The rifle does lunge forward as most spring-piston rifles do, but the shot is nearly dead calm. This is a masterful tune!

JSB Exact RS

The second pellet I tested was the JSB Exact RS dome. These pellets weigh 7.33 grains, which I think makes them ideal for an airgun of this power. Ten pellets averaged 626 f.p.s. with a 13 f.p.s. spread from 620 to 633 f.p.s. At the average velocity this pellet generates 6.38 foot-pounds at the muzzle.

Hobby

I think the power is probably very close to what it was in factory trim. Diana advertised the 26 at 650 f.p.s. in .177, and looking at what the JSB Exact RS pellets did I have to wonder what it would do with RWS Hobbys. So I shot a string of five and got the following numbers.

Shot…….Vel
1………..629
2………..638
3………..630
4………..637
5………..615

The average for that string is 630 f.p.s. and the spread is 23 f.p.s. At the average velocity Hobbys generate 6.17 foot-pounds at the muzzle. The lighter Hobbys are not quite as efficient as the JSB Exact RS pellets, which may mean the JSBs are better-suited to this powerplant. What all that entails I won’t discuss until I test the accuracy, because if a pellet isn’t accurate it doesn’t matter what it does through the chronograph.

Barrel tension

The barrel tension is adjusted quite tight. Once cocked the barrel remains where it is positioned because the base block is pinched tight between the action forks. Carel will probably deny any tuning skill, but I would be proud of a job done this well.

H&N Baracuda Match with 4.50mm heads

Now it was time to try a heavyweight pellet. I chose the H&N Baracuda Match with 4.50mm head. This domed pellet weighs 10.65 grains and, while there are heavier pellets in .177, this is a mainstay that’s worth a test.

This pellet averaged 489 f.p.s. for 10 shots. The spread went from a low of 483 to a high of 500 f.p.s., so 17 f.p.s. in all At the average velocity this pellet generated 5.66 foot-pounds of muzzle energy. I chose this pellet because in .22 caliber Baracudas are accurate, if slow.

Sig Match Ballistic Alloy

The final pellet I tested was the lead-free Sig Match Ballistic Alloy wadcutter. We know these are often quite accurate, plus I wanted to see how fast they would go in the 26. They averaged 763 f.p.s. (wow!) with a 64 f.p.s. spread that went from 732 to 796 f.p.s. I don’t know whether these will be accurate in this rifle or not, but they sure are fast. I expected 675 f.p.s. — not the mid-700s!

Discussion

That’s a total of 5 different pellets tested if you include the Hobbys. That gives us a pretty good idea of the power of this 26. As large as this rifle feels in the hands, I was expecting a little more, but it seems to be about the same as a model 27.

Cocking effort

The rifle cocks with an even 23 lbs. of effort. I knew it was more than the 27s I have tuned and that is due to the Maccari mainspring. Still, 23 lbs. is light cocking and this is an all-day air rifle.

Summary

Three months ago I had never heard of a Diana 26. Now I’m testing one! Ain’t life grand?

18 thoughts on “Diana model 26 breakbarrel air rifle: Part 2


  1. B.B.

    You are going to have to dig into the rifle to see why it shoots so smoothly. Seems to have the perfect spring in it!
    That are the spring dimensions? What kind of piston seal? Custom spring guide and top hat? What is the secret?
    Wish all springers shot so well…

    -Y


  2. B.B.,

    The Maccari spring Carel installed has a square cross-section if I remember correctly, which might have a part in this air rifle being so smooth. It sounds as if it might not really need Tune-in-a-Tube (TIAT).

    Michael


  3. Chris— Thank you for the information re the Kidde recall My replacement extinguisher is on the way. By coincidence, I had a visit by a rep of a large , local plumbing company. I am getting estimates re replacing my hot water heater. He did not know about the recall. I am going to contact my fire department to find out why they have not made the public aware of this problem. They have a large electronic message board outside the fire house. I have never seen any info re the recall on it. ——–Ed


  4. I also would also like to thank Chris for the heads up on the Fire Extinguisher Recall. I also had never heard of it, but my replacement is now on the way. Thanks again, Mike


    • Chris USA,

      My thanks too on your Public Service/Safety message on the recalled fire extinguishers!

      Must have been a 34 MILLION STEALTH recall; highly effective recall technology and MEDIA participation!

      shootski


  5. B.B.,
    I found it interesting that the Sig alloy pellets had such a high velocity, and put out 6.78 fpe versus the 5.66 fpe for the Baracuda Match pellets. Was the firing behavior of the rifle equally smooth with these pellets that are at the opposite ends of the weight, velocity, and energy spectrum?
    I did some further testing of my .22 HW30S yesterday with JSB RS 13.43 grain pellets versus H&N FTT 14.66 grain pellets. The heavier pellets travel at 450 fps, but the rifle fires harshly with them…harshly compared to the JSBs, that is; at 475 fps, the firing behavior of the rifle is so much smoother that it is like shooting a different gun.
    Is it normal for a springer to behave that differently with only a 9 to 10 percent change in pellet weight?
    Anyway, I’ll be curious to see the accuracy differences between the light and heavy pellets in this Diana 26.
    Thank you, take care, & God bless,
    dave


  6. Hi B.B. and all,

    I can take very little credit for the way the rifle shoots. I just put in the Maccari spring and cleaned and lubed it a little. I am pretty sure it actually lost a little power after the tune, but it shot so smooth I did not want to mess with it either.
    The credit should go where it is due, the fine people at Diana who made this air rifle. Because the trigger and the barrel pivot are all stock.

    All the best,

    Carel


  7. Ed, Whiskey, Shootski,….

    🙂 Glad you found it useful. Pass it on to any and all that may care.

    Again,…. go to the Kidde site and look for fire extinguisher recalls as well smoke detectors, ya’ all.

    Chris


Leave a Reply