Diana Stormrider Generation II precharged pneumatic air rifle: Part 2

by Tom Gaylord
Writing as B.B. Pelletier

Diana Stormrider II
Diana Stormrider Generation II precharged pneumatic air rifle.

Part 1
Stormrider Gen 1 Part 4

This report covers:

  • Fill
  • RWS Superdome
  • Discharge sound
  • JSB Exact Heavy
  • Chronograph
  • Last pellet
  • Discussion
  • Trigger pull and adjustment
  • Summary

Today we look at the velocity of the .177-caliber Diana Stormrider. I linked to Part 4 of my test of the .22 caliber rifle last year for comparison, but the rifle I’m testing today is a .177-caliber second-generation airgun, where that last test was a first generation. Part 1 of this report discusses the differences.

In Part 1 of this report I made a big deal about this Stormrider’s fill adaptor coming with a male Foster fitting on the end that connects to the hose of most air tanks. However, in re-reading the other report I see that the Gen 1 gun had one, as well, so Diana has thought this through from the very beginning.

Fill

I started by filling the rifle to 3000 psi (206 bar). That’s over the recommended fill pressure of 200 bar/2900 psi, but the fill went too fast to stop it in the correct place. The reservoir is small, so it fills fast.

RWS Superdome

The first pellet I tested was the RWS Superdome. This 8.3-grain dome averaged 1,043 f.p.s. out the muzzle for 10 shots. The low was 1035 and the high was 1053 f.p.s. for a spread of 18 f.p.s.  At the average velocity this pellet generates 20.05 foot pounds at the muzzle, so we are already at the listed energy. We are also above the listed velocity of 1,050 f.p.s., and we did it with a middle-weight lead pellet.

Discharge sound

The discharge sound is low for this power level. It’s too noisy for a small suburban back yard, but it is not offensive. A reader asked if the Diana silencer is equivalent to a TKO silencer and I have to say that it isn’t. A TKO does more to attenuate the discharge. But this one is doing a good job.

JSB Exact Heavy

I tried the JSB Exact Heavy dome dome next. The rifle seemed to fall off its power curve around shot 2 in this string which is shot 12 from the initial fill, so I will show you the entire string.

Shot…………Velocity
1………………991
2………………983
3………………976
4………………966
5………………966
6………………953
7………………950
8………………936
9………………931
10……………..923

Therefore, the following data is pretty useless. The average for this string was 958 f.p.s. The spread went from 923 to 991, a range of 68 f.p.s. At the average velocity this pellet generated 21.08 foot pounds at the muzzle.

To see whether I was right about the power curve I shot another RWS Superdome that went out at 970 f.p.s. That’s far below the average 1,043 f.p.s. I got on the first string.

There is something else that’s interesting within this string. Do you see how the velocity sort of stabilizes around 950/960 f.p.s. (shots 4 through 7)? That tells me the real drop-off point was there, rather than at shot 2 like I mentioned. Just looking at this data I will guess that if I were to run a second string after filling the rifle to 2900 psi again, the average with this pellet would be around 970-980 f.p.s. I’m guessing that if I were to re-run the test after filling, this pellet would probably generate around 22 foot pounds. Let’s test it and see. For this test I re-filled the gun to 200 bar/2900 psi.

Shot…………Velocity
1………………961
2………………972
3………………980
4………………988
5………………993
6………………989
7………………989
8………………990
9………………990
10……………..979

The average for this string was 983 f.p.s. The spread went from 961 to 993 f.p.s., a range of 32 f.p.s. At the average velocity this pellet generated 22.19 foot pounds at the muzzle. It looks like I made my velocity estimate after seeing these numbers but I didn’t. I guessed, based on the velocity I saw in the first string with this pellet. This also affirms my thoughts that the end of the power curve in that first string was around 950 f.p.s., and that gives us a shot count of 17 shots per fill.

Chronograph

I’m only setting these limits (shot count and power curve) based on the numbers we are seeing from the chronograph. You can choose different numbers and extend the shot count if you like. I am always thinking forward to the accuracy at 50 yards, where small velocity variations are more important, but if you are happy shooting at 25 yards, then don’t stop where I did. All of this is arbitrary and gets selected by the results you see. This is a good illustration of why you need a chronograph and to not just listen to the speed of the shot from your back door to the hickory tree.

If you don’t have a chronograph, just shoot groups at 25 yards or beyond and stop shooting when the pellets start to drop. That’s a practical way to operate.

Last pellet

This Stormrider is a powerful air rifle, so I’m not going to shoot ultra-lightweight pellets in it. I don’t want to break the sound barrier. The last pellet I will test is the Crosman Premier Heavy dome. This test turned out to be the most interesting of all, so look at the results and then we’ll talk. For this test I filled the rifle to 206 bar/3000 psi.

Shot…………Velocity
1………………882
2………………922
3………………919
4………………919
5………………926
6………………930
7………………950
8………………955
9………………962
10……………..966
11……………..974
12……………..977
13……………..978
14……………..972
15……………..971
16……………..970
17……………..965
18……………..959
19……………..949
20……………..943
21……………..937
22……………..931
23……………..922
24……………..913

The first comment I will make is that the gun was filled too high at the start of this string. The velocity increase over the first 6 shots tells you that. If we start our power curve at shot 6 and continue to shot 22, there are 17 good shots on this fill. Imagine that! But there is something additional to look at here.

Do you see how slowly the rifle falls off the power curve at the end? It seems to be fighting to keep shooting. If you don’t want to shoot 50 yards you can start the curve at shot number 2 and stop at shot 23, giving you 22 good shots on a fill. Or stop at 18 because that is two full 9-shot magazines.

I think the heavier Crosman pellet remains in the barrel longer, holding the valve open just slightly longer and giving this improved performance. If we go with the part of the curve I selected (shots 6 through 22) the average velocity is 958.12 f.p.s. The spread for that string runs from 930 to 978, which is 48 f.p.s. At the average velocity the muzzle energy is 21.41 foot pounds.

Discussion

Diana has given very conservative numbers for their .177-caliber Gen II Stormrider’s performance. They say 1,050 f.p.s. and we see more than that with a middleweight pellet. They say 20 foot pounds and we have seen over 22 foot pounds.

Also, this Stormrider likes heavier pellets the best. They seem to work well with the way the valve is set up.

Trigger pull and adjustment

The Gen II trigger is adjustable. Unfortunately Diana didn’t put the directions for adjusting it in the manual. I discovered that both the front and rear screws affect where stage one stops and stage two begins, and no amount of adjustment gets rid of all the creep in stage two. It came from the factory with a long stage one that was a pound and a short creepy stage two that breaks at 4 lbs. 15 oz. After a lot of fiddling I got the long stage one at a pound and a fairly crisp stage two at 5 lbs. 5 oz. I like a positive release over a light trigger so I’m leaving it where it is.

I don’t have any specific instructions for you. It seems like the front trigger is for the stage one length of pull and the rear screw is for the let-off weight. But both screws seem to affect both adjustments, so who really knows?

Summary

The Gen II Stormrider is shaping up nicely. It has good power, is reasonably quiet and gets a full two magazines per fill. If the accuracy is there this will be a best buy.

19 thoughts on “Diana Stormrider Generation II precharged pneumatic air rifle: Part 2

  1. B.B.,

    Looking at the Crosman Premier Heavy dome tabulation seem to show partial valve lock until the 6th shot, then stabilizing at the 7th to the 20th shot before dipping down further. I wonder what the pressure was by that 20th shot? Although the recommended starting pressure is 2900psi if the pressure was low enough the owner could make do with shooting one full 9-shot magazine before pumping it up again.

    Siraniko


  2. B.B.,

    Interesting. I seem to re-call that while your rifle may like 2900,…. mine might like 2700, if we are using the same pellet. Why? Due to valve differences. Also, as you pointed out,.. swapping pellets might dictate a different start fill to best optimize the shot count.

    Good advice too on just shooting if one does not have a chrony. I shot per bull targets would be ideal for that. (One important note: Note the fill pressure as you shoot so that you can replicate the best fill pressure). An example of that would be a fill of 2900 not coming on the curve until the tank pressure reached 2750. At that point, 2750 is your best start pressure for (your) gun and (that) pellet.

    As GF1 is always saying,… just because things appear to be coming off a “curve”,… sometimes the accuracy does not suffer. I have found that to be true in some cases.

    Looking forwards to the accuracy phase. 25 for sure and the 50 is always a treat.

    Good Day to one and all,….. Chris


  3. BB,

    That was a good little lesson about power curves and fill pressures. I remember that Talon SS I got from Mac did not peak on the power curve until the pressure was down to 1800 PSI. Knowing that saved me a lot of pumping.


  4. BB,

    Since Crosman Premier Heavies shoot at that high velocity, do you think shooting the other, lighter Crosman varieties at the even higher velocities they would bring to the equation would be likely to foul the barrel?

    Half


  5. B.B.,
    It appears like they moved the front sight back on this model; on the previous one, it was 4 or 5 inches forward of the end of the reservoir. Do you think that’s because they expect most people will scope it; and hence, not care about losing some sight radius? Thanks.
    take care,
    dave


  6. I was just at the PA site and it was interesting to see that Diana offers left-handed breech-blocks for a reasonable price.

    Think that that is an excellent idea and considerate of the 17 percent of the people who are left-handed.


    • Hank,

      It looks like the Stormrider south paw breech block may fit the whole suite of guns using this basic platform, it looks the same as the dragonfly. If so that will open up quite a few othe guns for lefties.

      Don


    • Hank,

      I too noticed that awhile back and commented as well. That is good to see. Looks like they are on Crosmans tail,… but they are going to have a long way to go. The low price point was actually a surprise. Some makers really rack up the mag. cost. Barrels and trigger options next? 😉

      (Ease) of parts access will be paramount. Plus diagrams. Anybody will have a LONG way to go beat Crosman on that point.

      Chris


  7. Looking forward to the accuracy phase on this rifle platform. Resisting the urge to make an adjustable transfer port out of the big brass one it comes with and a spring stop guide. 800 fps in the yard is fairly quiet out of the Bandit,
    now I loose my front post on anything that isnt bright at 25yds. This is the differance between the needs of a hunter, and the needs for a target shooter?I usually shoot scoped rifles. Also, there is no leade to speak of, so loading has been a little harsh, and may damage a pellet. As one of the 17%, it is nice that there is a left handed receiver option.
    Thanks Vana2 . Have a nice day,R


  8. I am also looking forward to the accuracy test. Like 1stblue, I purchased the bandit. I have only had it long enough to get the sights adjusted. They look to be the same ones on this rifle. The all black post was being a challenge to make a good sight picture against the black bullseye. My fix is to paint the very top edge of the post white. Maybe 1/16″ wide. For me it works and I can have a very repeatable aim.
    Gerald


  9. Evening Tom

    I did a video review on this gun (SPA version) and I found that the gun achieved the highest muzzle velocity of 934 fps at 155 bar; using Crosman Premier UltraMags of 10.5 grain. I got 51 shots from 200 bar with the lowest muzzle velocity at 703 FPS.
    If you are interseted, I can send you the link to the review.



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