The Air Venturi OmniStorm.
This report covers:
- Start
- Hobby pellets
- Where are we?
- JTS Dead Center 10.4 grain
- Gas spring pressure
- Next
- Nothing?
- Fill to 250 psi
- Fill to 300 psi
- Big deal
- BUT
- Trigger pull
- Next time
- Summary
Oh happy day! Today we start testing the .177-caliber Air Venturi OmniStorm. This test will take a LOT longer because I’ve never tested a power-adjustable gas spring gun in this blog! I’ve reported on them but never tested one.
Start
I started with the rifle the way it came from the box. It cocked on the heavy side but far from the heaviest I’ve ever seen. I figured it was set to power somewhere in the middle of the range. When I cocked it the rifle registered about 50 pounds on my scale. I say about because I can feel the cocking rod entering something like a spring guide near the end of the stroke and there is a small bump up in effort. Cock relatively fast and that bump fades to almost nothing.
RWS Hobby
Instead of an average I will show you the entire shot string. I fired the rifle 13 times with the RWS Hobby pellet for reasons you will see. I’m also not going to list both English and metric units today because this report is going to take a long time to write.
Shot….Vel
1………828
2………826
3………871
4………892
5………883
6………879
7………868
8………894
9………884
10…….889
11…….906
12…….891
13…….901
Okay, it’s obvious the gas spring needed to be cycled a bit before smoothing out. If we take the fourth shot as a start the low was 868 and the high was 906 f.p.s. That’s a difference of 38 f.p.s. The average velocity for this 7-grain pellet is 889 f.p.s. At that velocity it develops 12.29 foot pounds of energy.
Where are we?
If the online description is correct and the rifle does develop 1100 f.p.s. in this caliber we are on the high end of the middle velocity/power range.
JTS Dead Center 10.4 grain
Next I tried 10 JTS Dead Center 10.4 grain domes. I’ll show the entire string here, too.
Shot….Vel
1………693
2………696
3………701
4………703
5………712
6………720
7………715
8………722
9………719
10…….720
Again we see an increase in speed as the shots are taken, but this one was tighter. The low was 693 and the high was 722 f.p.s. That’s a difference of 29 f.p.s. At the average velocity of 710 f.p.s. this pellet developed 11.64 foot-pounds of energy.
Gas spring pressure
Now for what we all want to know. What is the pressure in the gas spring that produces these results? To find out I attached the OmniTuner pump and I pumped until the pressure no longer rose quickly with a pump stroke. That turned out to be around 450 psi.
The OmniTuner pump is attached to the rifle.
I must comment that this pump is EXTREMELY easy to operate! I worried about that because the $150 hand pump that came with the Beeman Crow Magnum/Theoben Eliminator was not! And it had no gauge so I never knew where the gas spring was.
To disconnect the pump hose turn the ENTIRE pump, hose and all as the fitting unthreads. The air pressure in the hose makes the knurled knob difficult to turn. At the point the pump’s air seal releases air you hear a small hiss and the threaded knob turns easily.
Next
The next step was to release all the air pressure in the OmniStorm’s gas spring and then start from the bottom of the power range. Just depress the pin in the center of the Schrader valve. The air rushed out instantly and there wasn’t that much!
Now, fill the gas spring. The website says 205 psi is the lowest it takes so that’s what I did.
I filled the rifle’s gas spring to 205 psi.
I then cocked the rifle and noted that it took right at 20 pounds of effort. I then loaded a Hobby pellet and shot. Nothing.
Nothing?
The pellet did not move from the breech. When I broke open the barrel to see the breech a small pop of air came out, so the piston did move, just not far enough to compress enough air to push the pellet. And by the way, that pop when I broke it open does prove that the breech seal works.
Why this happened has to do with individual airguns and this hand pump with its small pressure gauge. What we must do with THIS rifle is learn its operational boundaries, together with the pump we were given.
Fill to 250 psi
My next step was to fill the spring to 250 psi.
I filled the gas spring to 250 psi.
At this pressure the cocking effort was 25 pounds. Since the Hobby pellet was still in the breech I now fired the rifle through the chronograph. Nothing again. I broke the barrel open to see that the pellet was still in the breech and there was another small pop of air. The piston had moved again, just not far enough.
Fill to 300 psi
I connected the pump again and filled to 300 psi.
I filled the gas spring to 300 psi.
The rifle now cocks with 32 pounds of force. This time the pellet shot out. Ten Hobbys averaged 589 f.p.s. The low was 571 and the high was 609 f.p.s. That’s a difference of 38 f.p.s. The average velocity is 589 f.p.s. and at that speed this pellet develops 5.39 foot pounds of energy. Is this as low as this OmniStorm will go? We don’t know yet.
Ten JTS Dead Center domes averaged 414 f.p.s. The low was 406 and the high was 421 f.p.s. That’s a difference of 15 f.p.s. At that average speed this pellet develops 3.96 foot pounds of energy.
Big deal
Folks, this kind of performance has NEVER been achieved in the airgun world to my knowledge! My $1,300 Theoben Eliminator could vary from about 27-28 to 31 foot pounds in .25 caliber. At the SHOT Show I spoke with Ben Taylor, the ben in Theoben, and he told me that was pretty good performance for an Eliminator. I wanted to drop it back to 20 foot pounds to get the cocking effort down to the 35 pound range, but that was not possible at that time. Now we have it in a $200 package!
BUT
This test is not finished. It will be finished when I test the rifle again after a week of sitting still and see where these two pellets are. That will test the short-term leakdown tendency of the gas spring. I am not going to cut this rifle any slack!
Trigger pull
The single-stage trigger releases at around 7 pounds 3 ounces / 3.26 kg. I converted this one number for our international readers. It’s heavy to say the least. But I won’t know how it affects accuracy until I do some accuracy testing and that won’t be next.
Next time
I want to see if the rifle will function at a spring pressure of 275 psi and what that does to the performance. It might even work at a lower pressure because the gas piston seal is wearing in. I will test it.
I also want to take it up to 550 psi and see how it performs there. I will use today’s report as a blueprint for continued velocity testing. And the numbers given are not set in stone. Remember, we are working with THIS air rifle and THIS hand pump.
Summary
I am pleasantly surprised by the OmniStorm’s performance so far. I could do without the auto safety and the heavy trigger but in terms of gas spring performance it beats the 5 or 6 Theobens I have owned and/or tested over the years.
Until we test it in one week and see where it is, though, we still don’t know if this gas spring holds up. If it does and if the rifle is also reasonably accurate then this breakbarrel will be a world-beater!
Tom,
Does the trigger pull get heavier with the increase in pressure?
Siraniko
Siraniko,
It doesn’t seem to change. But of course I did not test it that way.
BB
Enquiring minds want to know.
That heavy trigger is not good. The .25 HW90 has a wonderful trigger. Unfortunately, it also has that automatic safety. I will have to look at it and see if it can be changed over to a manual. At least it is located in front of the trigger.
If that heavy trigger can be reduced somehow and this thing is accurate, it has a lot of potential. I need to get a pump and gauge for this HW90.
Have you heard any more about that gas spring for the HW95?
RR,
No In have not heard any more about the HW 95 gas spring. Have you contacted Tom Gore?
BB
BB,
No, I have not. It would probably be nice to have a gas spring HW50 or HW95 hanging around, but now that I have the HW90, I am good. I may change the caliber, but do not necessarily need another gas spring around here.
It has a wonderful trigger indeed – but it is a Weihrauch. If FM ever decided to acquire another gas-spring rifle – right now can’t visualize it being anything but an HW – would definitely get the pump/gauge combo to go with it. It would be in .22 caliber.
Seems the minimum gas spring pressure needed for this OmniStorm to operate properly is 300 PSI? Realize testing is not completed and it will take some time to work through the testing. No pressure, Tom. 😉
I think deep seating the pellet or choosing a smaller diameter pellet would allow the lower spring pressures to shoot. Just a thought.
Don
Don,
That is a wonderful idea. I will try it next time! Thanks,
BB
Sometimes after not shooting my break barrel rifles for a while I forget to use my official calibrated tool.
Benji-Don & BB
Skirts on Hobby’s may be too wide for some chambers. I was surprised at velocities I got on my HW30S with Hobby pellets. See comparison below with JSB Express 7.87 grain pellets.
HW30S & Hobby 7.0
410 fps
393
404
388
394
This pellet must be too tight for this barrel?
HW30S & JSB Express 7.87 which is most accurate pellet.
486
517
500
502
492
Average 500
Std dev 10.5
fpe=4.37
Those tests were from a few years ago when testing all my airgun velocities. I chose Hobby’s to see what the fastest a light weight lead pellet could do. This particular Weihrauch rifle was the only airgun I have that may be too tight for Hobby pellets.
Deck
That’s another reason to try deep seating. If you ever re-run those tests, it would be interesting to see what happens if you deep-seated the Hobby pellets.
Roamin,
Oh, I’m gonna do that.
BB
Roamin
Yeah, I’ll have to mull this over. My HW30S has been digesting only JSB and AA Express pellets for over a year. The bore is well seasoned based on the accuracy results. I’m hesitant to shoot other pellets in her.
Deck
This is already a fun series. Work day, got to go save the plant from young inexperienced contractor Machinist/Millwright pretenders so no Bacon grease pop corn. Just fueled up with Total and Community coffee, got to go.
So far, so good! Thanks for another excellent report.
This is all very interesting to me. I have a couple of questions though. It isn’t clear to me how the pump works. It appears that the top part (with the gauge) slides up and then I am guessing the operator would place a hand on the top of the gauge and push it down. Am I right?
Also your description that the piston isn’t moving “far enough” is a little bit ambiguous to me. Would the reason it doesn’t move far enough is that the pressure needed to move the pellet through the bore of the barrel is greater than the (adjustable) air pressure behind the piston?
Elmer,
Yes, that is how the hand pump works. And as I said, it is unbelievably easy!
Question number two. Yes, the pressure needed to move the pellet is greater than what the piston has compressed. But it HAS compressed some air. That’s why there is a small pop when the barrel is broken open.
BB
B.B.
Can you use the OmniTuner pump on your Theoben or Crow Magnum?
Seems the pump is the star here?
-Y
Yogi,
I no longer own a Theoben, but if I did that would be a good idea.
BB
I do! 🙂
Ridge,
if you ever think about it, this pump sure look like the Omni pump.
https://www.amazon.com/GIYO-Turbo-Shock-Bikes-Gauge/dp/B0CJBFZFXR/ref=sr_1_10?crid=2WVP1JRW1GXHM&dib=eyJ2IjoiMSJ9.X8uMvJVIn5Gsv4gJpVIyc5gnO10aPiY-GWRRAZJ7X19tPgp_079P9hfxlXj8jdAIWnaNoJVKzeo7brFesI0oYaSGRuwLv0PuTBapwXjX3ix950m1omThWE3dV9wIc54KdMXBN6PZUxdB_LSBpllKUEQ6tvGxY6gj2eUOfFRm_jL0oNMfPavdm-5N1TCTphib0sljlBJDMPhwJO2kIBPK742wSLAMXpVw6YeG2ZkFb9_aMCJgOktAheSPfbxVs3Rv98FEm7ZbWsTAB7ZtlTHoRBLohaT2Grugd7knBorfqRI.DARaZX2NkAMwnoW6NtcmnZoQy70RnCbz_c7b8qzIrxI&dib_tag=se&keywords=giyo&qid=1761156197&sprefix=giyo%2Caps%2C144&sr=8-10
Doc
Doc Holiday,
Sure looks like it to me.
Great find! The micro bleed button is interesting.
I wonder if the AV one has that feature?
shootski
Doc,
It probably is. It looks like Uncle Xi’s cohorts are getting together to invade us. It simplifies the design process, in addition to reducing costs, if you use something someone else has come up with. It is my understanding the Chinese are really good at that.
B.B.,
“This test is not finished. It will be finished when I test the rifle again after a week of sitting still and see where these two pellets are. That will test the short-term leakdown tendency of the gas spring. I am not going to cut this rifle any slack!”
Question: cocked or uncocked? At some point later in this testing would you please check Cold Bore Shot consistency/repeatability from a cocked (for a few hours) and an uncocked condition.
Observation: The Cold Bore shot MV (Muzzle Velocity) consistency will hopefully improve as the gas spring, piston, and compression tube learn to work together; if it doesn’t (even without the cocked uncocked test) this rifle will not be a really great pester.
shootski
shootski.
I’ll think about it.
“At some point later in this testing would you please check Cold Bore Shot consistency/repeatability from cocked (for a few hours) and uncocked?”
BB
Based on one of our readers’ comments a while back, can’t remember who it was, FM was storing the HW90 muzzle-down – supposedly that extends the life of the gas spring and delays the inevitable day when it will start leaking. Guess that would apply to any gas spring rifle.
You might consider putting a drop of silicone oil inside the gas cylinder when you increase the pressure. This might also be an option for RR’s HW-90, if you ever need to re-charge its gas cylinder.
Mike
This morning the PA site shows the OmniStorm to be “out of stock” for both .177 and .22 versions.
Basil,
I said get them quick. There will be more soon.
BB
FM,
We will probably be hearing/reading about the melted piston seals from over charging the gas spring. “Hey, if I put more air in here, I will get more speed!”
BB-
I got to wondering…
You bled out all pressure and then tested increasing pressures until you were able to fire the pellet. Would duplicating the test in reverse- reducing pressures until the pellet fails to fire- be useful to the readers?
Paco
P{aco,
That sounds good but there is no way to do it. It’s like letting the air out of a balloon with a pin.
BB
B.B.,
So the Omni Storm pump does not have the micro bleed feature as the pump that Doc Holiday found is equipped with?
shootski
shootski,
Thank you! Yes the pump has a micro bleed feature.
Next time,
BB
Readers, this is why this blog is so helpful. Mentor BB does not hide from any mistakes or oversghts. He obviously would make a terrible politician. The truth and nothing but the truth is what you get here.
Deck
Decksniper,
It certainly is an environment that Tom as built here that has all of us typically trying to be working together to gain REAL and accurate knowledge instead of the stuff you see on other airgun and firearm forums.
I like it!
shootski
Deck,
” He obviously would make a terrible politician”
Thanks! That’s the nicest thing anyone has said about me in a long time!
BB
B.B.,
Nichts zu danken ;^)
shootski
pacoinohio,
Interesting question!
I thought about it for a time and although it might be interesting to the readership it would only be useful to shooters who choose to use the same pellet/projectile and even then their pump, gauge, gas spring, and barrel are all going to be different even if only a little.
It is sort of like the Powder Reloaders who are always bugging folks for their HOT Load information instead of working up their own for their firearm. They typically don’t realize that each lot of powder is different, each chamber/barrel is different, each company’s brass cases are going to be different, and each batch of primers is different as well. In the end when they blow apart their pistol or rifle they wonder why and then go on to blame the shooter they asked for the load information.
It might be useful from the standpoint of an approximation to establish an extreme LOW to HIGH range but again only for one projectile.
Tom could be at this sort of testing until the cows come home.
shootski
Shootski-
It is an interesting question because mechanical devices can behave in apparently illogical manners. I seem to recall a frustrating experience with maintaining drifting torque values until I over torqued and then came ‘down’ to the proper number.
I was just curious if this gun (and only this gun) reacted the same way going both directions.
As for reloading centerfire cartridges, any ‘recipe’ regardless of source can only be regarded as an observed data point. It then requires your own testing by starting low and then working up to the maximum of the observed data point.
Too many want to skip the work up part.
pacoinohio
Your drifting torque values statement reminded me of the lesson on torquing a very experienced mechanic and all around great neighbor shared with me in Pensacola decades ago. His method was to torque to the value and then back off 1/2 turn. The stated reason was that the magnetic/electrical forces generated at the molecular level by the sliding surfaces would give false torque readings. By backing off the 1/2 turn it eliminated most of those forces and allowed for torquing to specification within the acceptable tolerance limits. He was a highly respected mechanic and shop foreman working on overhauls of complex US Navy helicopters.
Best i can tell it works. Hopefully Bob M will se this exchange and share his way more extensive knowledge than I’ll ever have.
shootski
Tom,
WordPress making its own schedule?
Siraniko
Siraniko,
It would seem so.
Believing, hoping, Omnistorm’s trigger can be fixed with no evidence yet. Otherwise its just coulda woulda shoulda instead of a great training tool.
For me the new built in laser rangefinding auto reticle adjustments in either Thermo or night sights for 600 to $700.00 is a big deal that increases hits with my HW90 in 25! Self contained ~20FPE, and hunting accurate anywhere on the way to about 50 yards. Just saying.