This report covers:
- RWS Hobby
- Discharge sound
- Air Arms Falcon
- Norma Golden Trophy
- Cocking effort
- Trigger pull
- The trigger
- Shot cycle
- The accuracy test
Today we look at the velocity of the Diana 34 EMS with the Vortek Diana 34 EMS gas spring conversion kit installed. I used three of the same pellets that were used to test the factory 34 EMS with its coiled mainspring, back in March of 2021, so we will have a direct comparison between the coiled steel mainspring and this gas spring. Let’s begin.
The coil spring developed an average 927 f.p.s. with the RWS Hobby pellet. It had a spread of 18 f.p.s.
The Vortek gas spring developed an average 1025 f.p.s. — a 98 f.p.s. increase in velocity. The low was 1021 and the high was 1030 f.p.s., so a 9 f.p.s. spread. At the average velocity this pellet produces 16.33 foot pounds of energy at the muzzle
The discharge sound is a healthy 109 dB. With the coil spring it was 101.3 dB, so the gas spring did add to the noise. None of the pellets broke the sound barrier, so the noise was all in the powerplant.
Air Arms Falcon
The second pellet tested was the Air Arms Falcon dome. With the coil spring this pellet averaged 919 f.p.s. with a spread of 49 f.p.s.
With the Vortek gas spring this same pellet averaged 1002 f.p.s. That’s an increase of 83 f.p.s. The low was 998 and the high was 1007 f.p.s. for a spread of 9 f.p.s. At the average velocity this pellet produces 16.35 foot pounds of energy at the muzzle.
Norma Golden Trophy
The final pellet I tested was the 8.4-grain Norma Golden Trophy. With the coil spring that pellet averages 835 f.p.s. with a spread of 17 f.p.s.
With the Vortek gas spring this same pellet averages 917 f.p.s. — an 82 f.p.s. gain over the coil spring. The low was 912 and the high was 921 f.p.s. — a difference of 9 f.p.s. At the average velocity this pellet produces 15.69 foot pounds of energy at the muzzle.
With the Vortek gas spring installed the rifle cocks with 35 pounds of effort. Compare that to 29 pounds the coiled steel spring takes after a small break-in. I guessed the gas-spring cocking was 28-29 pounds because it is so smooth, but the coiled mainspring also cocked very smooth. I actually thought the gas spring cocked easier than the coiled spring, so the smoothness really confused me.
The previous test of the two-stage trigger netted 11 ounces for stage one and 18 ounces for the release at the end of stage two. Today the trigger tested 12 ounces for stage one and 17 ounces for the stage two sear release. That’s too close to call. I say the trigger hasn’t changed.
In Part 6 reader gnom256 chastised me about my installation of the Vortek gas spring where I left the original Diana steel bushing out of the trigger assembly.
“Hi, Tom!Original trigger bushing is strictly necessary for correct trigger operation! You should to get it back as soon as possible!
The specified pressure is much higher than the permissible one too.”
So I called Tom Gore who had already assured me that the picture I showed you of his unit attached to the 34 EMS trigger was correct. Tom said:
This trigger is not a T06 trigger. It is a T06 that has been modified to accept an N-TEC gas spring that Diana never produced for the 34 EMS. I showed them my unit and Diana engineers have blessed it as correct for the 34 EMS trigger.
The 34 EMS now shoots dead smooth. There is a pulse but until I test the accuracy I can’t say more than that.
The accuracy test
I’m going to hold off shooting for accuracy until Vortek sends me one of their new barrels. The EMS is a modular system and a barrel swap is supposed to be part of the deal. Vortek will now make this possible. If I test the accuracy with the factory barrel I’m not doing anything I didn’t already do in Parts 3, 4 and 5, back in 2021.
I said in Part 6 that this gas spring conversion could be a complete replacement for the Sig ASP20 air rifle that’s no longer available. Today’s test shows that the power of this unit falls short of the ASP20 power. I don’t own a .177-caliber ASP20 to test for velocity, but the number 20 in the title indicates that in .177 caliber that rifle gets 20 foot pounds of energy. The 34 EMS has hit just below the mid-16 foot-pound range. As far as accuracy goes, we will have to wait for that test. And remember, this kit is available right now.
The Vortek Diana 34 EMS gas spring conversion has now been installed and tested for velocity in my .177-caliber 34 EMS. It installs easily and the velocity is a sharp increase over the factory mainspring, with a corresponding sharp increase in consistency.