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Education / Training Diana Mauser K98 PCP rifle: Part 3

Diana Mauser K98 PCP rifle: Part 3

by Tom Gaylord
Writing as B.B. Pelletier

Diana Mauser
Diana Mauser K98 PCP.

Part 1
Part 2

This report covers:

  • Trigger adjustment
  • Sight-in
  • JSB Hades
  • Beeman Kodiak
  • JSB Jumbo Heavy
  • RWS Hobbys
  • H&N Hollowpoint
  • RWS Superdome
  • Discussion
  • Summary

Today is the first day I test the accuracy of the new Diana K98 Mauser PCP.

The test

I shot the rifle with open sights off a sandbag rest from 10 meters. I shot 5-shot groups so I could test more pellets.

Trigger adjustment

I said in Part 2 that I would adjust the trigger today, so let’s get to it. There is just one screw to turn and clockwise decreases the sear engagement. I turned the 2mm screw clockwise as far as it would go and then tested the trigger by hand. It felt lighter and had less creep than it had before the adjustment. My trigger pull gauge records the 2-stage pull as still breaking at over 12 pounds. It is still creepy, though not as much as before. And that’s that.


I didn’t bother with a sight-in because I was shooting with the open sights that came on the rifle. They should be pretty close to right on — except they are not! My first pellet hit the target a quarter-inch high and a full inch to the right. Since this rifle has no provision for lateral adjustment I guess I’m out of luck with this pellet! And what a shame — it is the most accurate pellet that was tested today!

JSB Hades

The sight-in pellet was a JSB Hades and three of the five pellets landed in a tight group. Then I got careless and messed up a good group. But that was my fault so I pulled out all the stops and did my level best to shoot a good second group. This time five .22-caliber Hades pellets landed in 0.302-inches at 10 meters. For open sights that’s darn good. It’s three-tenths of an inch to the left and a half-inch high but it is a group I can work with — AS LONG AS THE SIGHTS ARE ADJUSTABLE! But of course they aren’t

Diana Mauser Hades group
The Diana Mauser PCP put 5 JSB Hades pellets in 0.302-inches at 10 meters.

The rear sight does adjust up and down on a stepped ramp, but I have it set as low as it will go. The front sight does screw up and down if you have the right tool, but Diana included no sight adjustment tool with this rifle I’m testing. Can I make do? Sure but it doesn’t cure the left and right problem.

Now, the rifle can be scoped and I do plan to test it with a scope. But this is a replica airgun, — a replica of a military rifle. It’s not supposed to need or have a scope. If you want an accurate PCP there are plenty around. This is a replica, and it misses the mark by not having sights that are regulated to hit the target. That is a serious shortcoming in my book.

Hunting Guide

Beeman Kodiak

Okay, let’s try again. Maybe we’ll find the pellet that goes right to the point of aim. Well — it isn’t the Beeman Kodiak! That pellet hit the target 1.7 inches above the aim point and three tenths to the left. I am aiming at 6-o’clock on the bullseye, so really the pellet is landing 2.3-inches high at 10 meters. The group measures 0.4-inches between centers — another decent  group for open sights at 10 meters, but it’s in the wrong place and I can’t do anything about it.

Diana Mauser Kodiak group
The Mauser PCP put five Beeman Kodiaks in 0.4 inches at 10 meters, but look where they are!

JSB Jumbo Heavy

Next I tried so 18.13-grain JSB Jumbo Heavy pellets. Since the Hades pellets did so well I thought these might also. And they did, sort of. I can’t say for certain how large this group of five is because I had also shot one Beeman Kodiak at the same target by mistake. Who knew that the JSBs would group in the same place? Oh well, the total size of this 6-shot two pellet group is 0.507-inches between centers.

Diana Mauser Jumbo group
Five JSB Jumbo Heavys and one Beeman Kodiak went into 0.507-inches at 10 meters.

RWS Hobbys

Next I tried 5 RWS Hobby pellets. This is a Diana air rifle, after all, and Dianas like RWS pellets. Or, that is to say German Dianas like RWS pellets. This rifle was made in China, so all bets are off.

Five Hobbys made a 1.07-inch group at 10 meters. After what we have seen, this is not the right pellet for the rifle. The center of the group is 1.7-inches above the intended target and 0.33-inches to the left. This left and high placement is an ongoing thing with this rifle, no matter what pellet is tried.

Diana Mauser Hobby group
Hobbys are not the pellet for the Diana Mauser PCP. Five went intro 1.07-inches at 10 meters.

H&N Hollowpoint

Next I tried five H&N Hollowpoint pellets — mostly because I was grasping at straws. Five made a very horizontal group that measured 1.1-inches between centers. It’s the largest group of this test.

Diana Mauser H&N Hollowpoint
Five H&N Hollowpoints made this horizontal group at 10 meters that measures 1.1-inches between centers.

RWS Superdome

The last pellet I tested was the RWS Superdome. Five of them went into 0.698-inches between centers at 10 meters. Three are tighter, indicating that this might be a pellet to try again.

Diana Mauser Superdome group
Five RWS Superdomes made a 0.698-inch group at 10 meters.


Today’s test results disappoint me. The Mauser PCP appears to be a very accurate air rifle, and that trigger that everybody thinks is way too heavy is no problem at all. But to have sights that don’t work as they should — shame on you, Diana! You had best learn how to make sights that work — or get your Chinese factory to do it, because this is an unforgivable error on an accurate rifle. And tell your marketeers that if the front sight is on a screw post — WE NEED THE TOOL TO ADJUST IT! Especially on this rifle that shoots so high.


What do we have in this Mauser? It’s quiet, but short on breath. It has decent power. It’s very realistic but the sights don’t work. It’s quite accurate, but not as a replica. You have to mount a scope on it.

This air rifle is a conundrum. They got it 80 percent right but that other 20 percent is aggravating!

author avatar
Tom Gaylord (B.B. Pelletier)
Tom Gaylord, also known as B.B. Pelletier, provides expert insights to airgunners all over the world on behalf of Pyramyd AIR. He has earned the title The Godfather of Airguns™ for his contributions to the industry, spending many years with AirForce Airguns and starting magazines dedicated to the sport such as Airgun Illustrated.

32 thoughts on “Diana Mauser K98 PCP rifle: Part 3”

    • Edw
      No doubt about it, there does seem to be lots of compromise going on to get the look just right and make modifications for it to function very similar to the firearm. Like putting bb’s, CO2, a hammer and an air valve in a mag for instance. The rush was on.
      Bob M

    • Edw,

      I disagree.

      Accurate, shootable replicas belong in the airgun world. The issue here is not putting a product in the wrong market. The issue is putting the wrong product in the market.

      Diana has made it easy for us to analyze this new PCP, by comparing it to their excellent (springer) K98 – also a replica. That gun is accurate and a fine product. It deserves it’s price. I’ll shoot it any day. The performance is just too good.

      This PCP, however, falls short on performance. It doesn’t meet the accuracy expectations. Or at least – the SIGHT expectations. No windage adjustment??? I mean, come on! 100% agreed with BB that a replica – and especially a K98 – is best with open sights. Some might scope it and I don’t fault them. But I wouldn’t.

      And the shot count and extreme spread… regulated or not, it’s just too much. Doesn’t seem to fit in today’s PCP market. Seems behind the times.

      The better features of this gun are two-fold:
      1. Getting a functional bolt handle on the gun is a GREAT feature.
      2. Putting a PCP powerplant into a replica. Seems like there is a lot of potential here. I’d like to see more manufacturers use it. Could give us more options for shooting long distances.

      I was so pleased when Diana announced this product last year. But I’m feeling empty, looking at the finished product’s performance.

      As much as I like replicas – and especially WWII – it has to perform.


  1. Seeing as how different pellets are impacting both to the left and right of the POA, as you said, the only solution here is for some kind of windage adjustment. Factory regulation might help with the lack of elevation adjustment, but in my mind, that’s not as big of an issue.

    And if it was meant to be scoped from the get-go, then it seems a bit amiss for Diana to not offer a scoped configuration for sale with appropriately vintage-looking glass to go with it.

  2. What a disappointment; as stated, if you want a replica, it must work as the real thing.
    Diana needs to ask for upgrades from the manufacturer. Adjustable sights and a small magazine for me.
    I can’t wait for R.R. to comment on today’s post…

  3. BB
    Very disappointing. I still have not shot mine to offer a comparison. I will ‘try’ to do so as soon as I can.

    I take apart almost every airgun I get to see how it works and is put together and have found a lot of inner barrels that have what I consider lots of play. Some are spring loaded and others are actually used as the hammer (M11).
    In most cases I usually shim them tight with aluminum tape to improve the accuracy a little trying not to affect the operation
    This rifles total lack of consistency leads me to believe something is not right. There is a piece of plastic that sits on the end of the barrel, inside the outer barrel / shroud assembly that may be clipping the pellets if its deformed? It’s close. And I’m not sure yet but that plastic part may be helping to center up the inner and outer barrels and any movement or misalignment in the outer barrel might affect the accuracy? The outer barrel slides over the inner. A loose set screw there?
    I’ll see if I can find any possible reasons for the inaccuracy. If mine is the same !

  4. BB,

    Putting it as nicely as I can, the Diana Group messed up big time with this one. They soiled the names of Diana AND Mauser at the same time when the marketeers came up with this idea.

    The real shame of it is that it could have been done right. If it were not for the baffles, the adjustment issue probably could be easily corrected with shimming. I know everybody wants the sights to be adjustable for windage, but if it is made right that is unnecessary. I have owned Brazilian Mausers. Clean out the cozmalean, load it up and bust 2 liter soda bottles at over 250 yards with no sight adjustment. Oh yeah.

    As for the trigger, I have pulled on some pretty heavy ones in my time. Like you have said, I can work with them. That is if they break crisply. A new PCP breaking like this? No excuse.

    The major problem here is that to keep cost down, they had this made in China. Diana has been somewhat fortunate that the “Sport” series has been somewhat successful, but this is a disaster. What is a real shame is the sproinger K98 looks and works nicely. Of course it is built around a very successful and well proven German air rifle and it is made in Germany, not China. It is also more expensive.

    This is not a bad idea. It is just poorly executed.

  5. B.B.

    I think “disappointment” is an understatement! 12 lbs trigger pull? Yes, B.B., the man with a million trigger pulls, can use it. Not me, or most people.
    Bad sights, why bother?


  6. I wonder if the Williams WGRS 54 sight is tall enough to clear the magazine?
    Lots of compromises with this gun from the manufacturer. The super short upper handguard and rear sight placed too far forward are hold overs from the under lever version. Well, okay. I get that. A 12 pound trigger on a pcp? Yeah. Well, it’s probably a plinker anyway. Can’t hit where the sights are pointing? Man oh man, seems like they’re just piling on, trying to get you to not like it.
    If the manufacturer isn’t willing to address the sight issue, seems like an opportunity for some aftermarket intervention. A replacement rear sight leaf ala an RPK style combo windage and elevation adjustment or maybe a slip on or slip in barrel tuner.

      • If you look at one of your Mausers, you’ll see the rear sights are much closer to the rear. The air guns- underlever springer or pcp- are much farther forward. The firearms have the advantage of registering the sights on a monolithic steel barrel. PCP- straw barrel within a shroud- not so much. However, my $30 Daisy 880 is built the same way (And in China to boot) and shoots where it’s aimed. But of course the rear sight is adjustable. With the available power on tap, please Diana, let it shoot!

        • Paco,

          I will have to look at pictures now. All of my Mausers have found new homes.

          Yep, they are more forward. The sproinger K98 does have adjustable rear sight.

          If you have sights that do not line up with shoots, you can VERY CAREFULLY bend the barrel. As for this thing, not so much. Take out the baffles and shim the straw. It will be louder, but not as much as an eight millimeter cartridge.

  7. Unbelievable, 12 pound trigger, and no windage adjustment. I don’t think any rifle without fully adjustable sights could ever be ‘built right’. It’s brand new junk-in-the-box. Perhaps it could be salvaged with an aftermarket rear sight.
    Good job B.B. for calling out Diana on this one.

  8. B.B.,
    It’s a little fuzzy when you zoom in on the right-hand side of the front sight, but it appears to be a band clamp assembly that is slipped over the barrel. Is there a way to loosen that band to allow the front sight to be rotated left or right for a windage adjustment? Hmmmmm……

      • B.B.,

        Barrelband has screws i would loosen shoot a group followed by tightening and trying another group. Given a cap over the barrel shroud it could be all it takes…some feverish worker in China could easily be effecting the design functionality by varying the screw torque values!


  9. The scary part is there may be a warehouse some where full of these things.
    At least they’ll have got the “surplus” part right. Hey, it’s got a wood stock on it.
    It’s disturbing here at night. When I was a kid, we played with all the usual fireworks, but what I am hearing
    are large explosive charges detonating in a residential neighborhood. Completely illiegal, and the police do nothing. The county looks the other way. These things will maim or kill, sadly, some idiot will light a quick fuse,
    and learn the hard way. And, my dog hates it.
    Be careful,

  10. BB,

    Completely off topic so I’l make this quick. Recently had a relative ask me if I wanted an old bb pistol. Being me I immediately said yes, but the gun turns out to be a mint Crosman 130. Better than that it still had all the original paperwork with it. After reading through the owners manual it clearly says not to leave any air in the pistol.

    My question to you is, is that lawyer talk or engineer talk? I’ve been leaving 01 pump in my other 130’s and 137 for years with no problems. As long as the seals are good they all hold that 01 pump just fine. If it’s engineering at play what would be the reasoning behind it?

    The date on the sales receipt is May of 66 so I know that it was probably resealed. It shoots just fine and with JSB 14.3’s, 20 gage shotgun hulls at 15yds are in serious danger!

    Have a good one!


  11. BB,

    I completely understand what you are saying, so let me ask this from a different perspective. Technically speaking, which is actually better for the longevity of the guns power plant when not in use? 01 pump or no pump.

    Thanks for the info!


  12. I was just checking over at Pyramyd AIR and they do not carry the sproinger K98 anymore. Maybe they should send these back and restock the sproingers.

  13. Know both the BB and the manual make no mention of windage adjustment….and there is not one built into the rear sight.

    But I keep coming back to the close up pixs of the front sight….sure looks like it was made for gross elevation adjustments (screws up and down) and the round part the blade/ post screws into what looks like could be pused a bit to one side or the other….doesn’t look like the Springer versions front sight (which does look fixed-fixed).

    Kind of like the orginal centerfires in function….had to drift the front sight for windage.

    Then again….if that were true, you’d think the factory manual would mention it (or BB confirm).

  14. I know this may be necro’ing the post but the front sight is windage adjustable. You need the SKS/AK forsight tool to do so. The tool even will adjust the up and down.

  15. I don’t own the gun, but I am pretty sure that the windage adjustment is on the front sight. AKs are the same with an offset aiming point of the front sight so it moves relative left/right on rotation.

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