Diana model 26 breakbarrel air rifle: Part 2
by Tom Gaylord
Writing as B.B. Pelletier
The Diana 26 air rifle.
This report covers:
- This is a .177
- RWS Superdome
- Firing behavior
- Trigger pull
- No vibration
- JSB Exact RS
- Barrel tension
- H&N Baracuda Match with 4.50mm heads
- Sig Match Ballistic Alloy
- Cocking effort
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.
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.
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.
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.
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.
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.
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.
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!
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.
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.
Three months ago I had never heard of a Diana 26. Now I’m testing one! Ain’t life grand?