Diana 27S: Part 7
by Tom Gaylord
Writing as B.B. Pelletier
This report covers:
- Diana peep
- Sight base
- Remove the rear sight
- The test
- Sight in
- First group
- Using the peep
- JSB Exact RS
I must love you guys to go through what I did this morning. Either that or I’m just as interested in this as you all are. Today I mount a Diana peep sight on the Diana 27S and test it for accuracy — at 25 yards!
Yesterday I wrote about peep sights. Well, getting ready for this article was what inspired that report — which has turned into a series! Chris USA asked me if I was ever going to discuss the high-end peep sights. That is what I’m doing today. Diana has had peeps of all grades. I showed you two of the lower grades yesterday. But today I’m mounting the top grade Diana peep to the 27S because this rifle was made for it!
Here are two top-grade Diana peep sights. The one on the left is older and on the right is the newer one. Notice that the older one is marked with German markings for adjustment and the newer one is marked in English. Both have structures made from aluminum with steel parts.
I’ve removed the central wheel for tightening the sight on the rifle. Note the small square piece that locks the sight to the rifle. Sorry about the depth of field in this picture.
Here you see the underside of the lock that joins the peep sight to the sight base on the rifle. Notice that it is threaded on all 4 sides.That’s how the locking wheel shown in the last picture presses it down onto the sight base.
For decades I have called the raised dovetail that’s found on the rear of many older Diana spring rifles a scope base. It does work for that, but that is not what it was intended to do. It is actually a base to accept the Diana target peep sight that I am mounting today. The fine ridges along the top of base interlock with the ridges on the sight lock just shown to make the sight secure.
The ridges along the top of the Diana sight base interlock with the ridges on the underside of the sight when they are pressed down by the big wheel.
Remove the rear sight
To use the peep I had to remove the rear sporting sight that was in the way. It is held to the rifle by two Phillips-head screws.
Okay, that’s a lot of work already, but this is supposed to be an accuracy test, so let’s get on with it. I will shoot from 25 yards today, but first I have to sight in. Since the peep sight is attached to the rear of the spring tube and this is a breakbarrel, there is great potential for barrel droop. I decided to shoot both Air Arms Falcons and JSB Exact RS pellets in today’s test, because they were best at 10 meters in the last test.
After mounting the older peep sight I fired the first pellet from 12 feet. The first Falcon hit a half inch below the aim point (6 o’clock on the bull) which was 1.5-inches below the center of the bull. It will rise when I shoot from 25 yards, so I did not adjust the height.
I did adjust the sight to the left about 5 clicks. This peep is a German sight, and has the German word bei between L for left and R for right. Think of the word bei as meaning “too”. It actually means “of” but I believe it is an idiomatic German part of speech. If you think of R as “TOO Right”, then you will turn the adjustment knob in the direction of the R to move the strike of the round away from being too right and to the left. It’s the reverse of how we think of it in the US, but it works.
The second shot went into the first hole, so I adjusted another 2 clicks to the R. This time the pellet moved to the center of the bull, but still too low.
At 25 yards I knew the strike of the pellet would rise from where it was at 12 feet, but I didn’t know how much. The first shot landed even with the center of the bull but 2.5-inches to the right. Five more clicks to the R and the next pellet moved an inch to the left. Eight more clicks and the pellet hit inside the bull, slightly high. I shot four more times without looking for a group of five. They are 0.507-inches between centers and slightly high and slightly left.
The Diana 27S put 5 Falcon pellets into 0.507-inches at 25 yards.
Using the peep
I must comment that, although this rifle has a tapered post in front, it is really east to aim with precision. That Diana peephole is very small and it gives my sighting eye a tremendous depth of field. An aperture up front would be better, but I don’t think the difference would be that great.
I felt so encouraged from that first group that I shot another 10 Falcons at the next target, after adjusting the peep two clicks to the right and 4 clicks down. That was almost perfect and 10 Falcons made a 1.198-inch group at 25 yards. Nine of them are in 0.732-inches. There was no called pull but I do think that low shot was an aiming error. I think the other 9 are representative of how well this rifle can shoot.
Ten Falcons are in 1.198-inches at 25 yards, with 9 in 0.732-inches.
JSB Exact RS
The other pellet that did really good last time was the JSB Exact RS. I decided to shoot 10 for another group. The first shot landed 2.2-inches low and three-tenths of an inch to the right. So I put in two clicks to the R and 8 clicks to the H (hoch, German for high). At that point the peep ran out of right adjustment. The next pellet hit the bull at 6-o’clock, just inside the black. It’s not centered for elevation but I can see that adjusting it up would be very easy, so I left it where it was and shot another 9 without looking. In the end there were 10 pellets in 0.705-inches at 25 yards. Yeah! This Diana 27S is accurate!
Ten JSB Exact RS pellets went into 0.705-inches at 25 yards.
I am surprised that the 27S grouped so well. I expected groups of an inch, but as you can see, with the right pellets it shoots much tighter. The rifle is so smooth that it’s easy to shoot this well.
This rifle is a very accurate .177 Diana. Until I tested my Diana 35 I had not seen one of the vintage .177 Dianas that were very accurate. I never tested my 35 at 25 yards, but it doesn’t have the sight base. so I would have to shoot it with the sporting sights. I really think the peep sight made all the difference today.
This series has been a long, involved look at an air rifle I didn’t know existed until Carel informed me. It has an anti-beartrap device, but during my assembly I must have put a washer in the wrong sequence because it isn’t working now. I can uncock the rifle by restraining the barrel and pulling the trigger. That is exactly the way I want all my Diana breakbarrels to function and all the parts are in the rifle if I ever feel the need to make it operational again.