Diana K98 pellet rifle: Part 2
by Tom Gaylord
Writing as B.B. Pelletier
This report covers:
- RWS Hobby
- Why is it so easy to cock?
- H&N Baracuda Match 5.51mm heads
- JSB Exact RS
- Trigger pull
- Loading is fiddly
- Evaluation so far
- Evaluation so far
Today is the day I test the velocity of the Diana K98 air rifle for you. A lot has been written about these rifles. Much of it has been good, but there have been a few comments that were not so good. One of them was from one of our readers who got his rifle before I got mine and he reports things like hard cocking and difficult loading because of the placement of the rear sight. He also takes exception to the location of the sling on the left side of the rifle, but that is a Mauser design and had to be put there to match the firearm. I won’t comment on that, except to say that a Mauser sling makes a rifle easier to carry while slung than a Springfield-type sling, but not as convenient for shooting as a hasty sling (look it up).
This comment came from reader Zimbabweed, who wants to be called Zimbabwe Ed. His last comment was that the cocking lever on his rifle comes loose and falls down when he shoots. He calls it the loading lever, but we are talking about the same thing. I will be watching for that today.
I’m interested in the rifle’s performance. Today is velocity day, so that’s what I will test. The specs provided by Diana on the Pyramyd Air website say to expect velocities in .22 caliber in the range of 850 f.p.s. Naturally Diana tested that with lightweight pellets and, since they are in Germany, along with RWS, I am going to assume they tested with the RWS Hobby pellet. So, that’s what I’m going to start with.
Hobbys averaged 909 f.p.s. in the test rifle. They ranged from a low of 903 f.p.s. to a high of 917 f.p.s., so a spread of 14 f.p.s. That’s pretty good for a brand new spring rifle in this power range.
Speaking of power, I hope this test silences all those who say the K98 is not up to spec. According to the manual they make this gun in 4 different power ranges. In .22 caliber they are 7.5 Joules, 16.5 Joules, 30 Joules and 35 Joules. That’s 5.5 foot-pounds, 12.2 foot-pounds, 22.1 foot-pounds and 25.8 foot-pounds. At an average velocity of 909 f.p.s. the Hobby pellet generates 21.84 foot-pounds of energy at the muzzle, so this rifle must be a 30-Joule airgun. That is a powerful spring-piston rifle, but it’s not quite a mega-magnum. Perhaps that is why it shoots so smoothly.
Why is it so easy to cock?
I was surprised by the power. The RWS 460 Magnum I tested for you in 2008 was a .177, so we are in an apples/oranges situation. The only thing I can compare is the cocking effort. my test K98 cocks with 41 lbs. of effort. That’s a lot for me to cock — so why is this so easy? Simple — the fulcrum is high on the rifle and cocking is a matter of pulling down! I rest the butt on my right leg and that puts the lever so high I almost use my weight to cock the rifle. Not quite, but almost. It is very easy for me to cock this rifle because of this.
The velocity and cocking weight also tells me this action is more than likely an unmodified RWS 460 Magnum action. The 460 Magnum I tested in 2008 cocked with 47 lbs. of effort. I thought this one would come out around 35 lbs. but it’s more than that. The placement of the fulcrum makes a big difference for me. This rifle is easy to cock with one hand for me. If the fulcrum were 6 inches lower on the rifle (closer to the butt) I would have to bring my core muscles into play when cocking and it would be a 2-hand operation.
H&N Baracuda Match 5.51mm heads
Because of the power I tested H&N Baracuda Match pellets with 5.51mm heads next. I expected to see velocities in the mid 700 f.p.s. range. Instead, though, the average was only 604 f.p.s., with a spread from 596 to 613 f.p.s. That’s 17 f.p.s. difference. But why so slow? Well, when I fired the first shot I felt the rifle shudder. It was vibration, but not from the mainspring. I will guess what I felt was the piston bouncing back and forth as the rifle fired, and that took away from the efficiency of the rifle. A heavier piston would not bounce as much and would probably generate more velocity, but instead of tearing the gun apart to modify it, I’m just going to shoot a lighter pellet.
By the way, at the average velocity, this pellet is generating 17.1 foot-pounds of energy at the muzzle. That’s 5 foot-pounds less than Hobbys and it is diagnostic of something that’s not right. Dropping 3 foot-pounds isn’t so bad, but when a gun drops 5 foot-pounds in this power range, you know something is up. The vibration I felt upon firing is now more important because we have evidence of far less power than expected. This is why owning a chronograph is so very important for an airgunner!
JSB Exact RS
The last pellet I tried was the 13.43-grain JSB Exact RS dome. This pellet is often an accurate one and it’s also lighter. I think the K98 can handle heavier pellets, but I wanted to see if my prediction about the piston bounce was correct. Apparently it was because the rifle was as smooth with this pellet as it was with the Hobbys.
Ten JSB Exact RS pellets averaged 830 f.p.s., which is 20.55 foot-pounds. The spread was large, though. It went from a low of 821 f.p.s. to a high of 852 f.p.s. That’s 31 f.p.s. I was going to tell you that the next-fastest shot was 829 f.p.s., but shot number 9 registered 839 f.p.s. So the spread is real, and not just one anomaly.
The two-stage trigger breaks at 1 pound 11 ounces. That is phenomenal! Sporting rifles like this usually go over 4 pounds. Stage two does have some creep, but I’ll live with it.
Ed, I never saw the cocking lever fall out of place once as I shot the rifle. I wasn’t supporting the forearm at all, so perhaps that is the difference. All I can tell you is this rifle is functioning as advertised.
Loading is fiddly
One of Ed’s complaints is the rear sight hangs over the loading port, making the rifle difficult to load. I have to agree with that observation. I took a picture of it so you can see.
I find if I stand the butt on my leg, the barrel is almost straight up and loading is as easy as it gets. But the K98 is not a fast-loading air rifle.
Evaluation so far
In my opinion, the K98 is a winner at this point. Of course I haven’t seen the accuracy which is everything, but a number of people including Pyramyd Air’s own Tyler Patner have told me the rifle is accurate, so I’m expecting the best.
As I said at the start, I intend shooting with open sights, because for me this rifle will always be a Mauser. But I will mount a scope and test it that way, too.