What's the highest power achieved in a .22 gauntlet?

[darkcharisma]

Behold Bob, its only 4 inches give or take 1/4 inch length worth of metal shavings i cut off. so 4.25 inches from valve transfer port to back of regulator block. and if you want a true measurement. its 3.57 inches from back of reg block to the valve threads. isnt that 25cc with .748id?

[rsterne]

I am confused.... You machined off the sides of the valve, yes?.... A stock QB valve is about 5 cc inside, but the front of the valve would take up more than 1" of that 3.57" length.... It looks to me like the stock plenum is only 2 1/4 - 2 1/2" long, or about 16-18 cc, plus the valve volume.... If you can give me the distance from the front of the valve to the back of the tank block, then I will know for sure....

Bob

[darkcharisma]

Bob, that is actually a stock Gauntlet valve unlike the QB78 stock valve. The sides of the valve have been machined from the factory or as you see in the picture. I now call front of the valve simply "valve spring housing". so from the valve spring housing to the back of reg block, is 2.6 inches. with the valve sides machined like that, it gives way for better flow and available air is closer to the valve transfer port than at the front depinger port.

[rsterne]

Thanks for that.... Yes, I would say that including the valve volume the plenum is about 25cc.... That is close to the shortened QB78 tube I had, which was 30cc including the valve.... It had lots of power in .22 cal, and decent efficiency.... but I felt it would have been too small in .25 cal, so I used a full '78 tube (51 cc plenum) for that....

Bob

[darkcharisma]

Bob, is there a write up on a QB in .25? I am also eager to see what you did to your .22 QB to get lots of power, it's settings and efficiency.

[rsterne]

Duy, the .22 cal with the shortened QB78 tube was done before I joined the GTA.... but the first thread linked below has the details.... The .25 cal. had a reversed tank block, so the whole '78 tube was available as a plenum.... That is in thread #2....



My QB modding threads are mostly in the Workshop.... here are the ones I found in a quick search....

https://www.gatewaytoairguns.org/GTA/index.php?topic=21681.

https://www.gatewaytoairguns.org/GTA/index.php?topic=25524.0

https://www.gatewaytoairguns.org/GTA/index.php?topic=49943.

I addition, anyone modding a QB should read this thread on the safety of the tank block installation....

https://www.gatewaytoairguns.org/GTA/index.php?topic=105712.20

Bob

[darkcharisma]

excellent reads Bob, love the .25 tank block power and efficiency at 1600 psi. when I get the time to work on my Gauntlet again, I am going to max it out. I think i hit the plateau at 35-40 fpe at 1200 psi currently, I will put the work on here once it's done in a couple of weeks. It's so much fun modding the QB series, Troy Hammer even converted some QB78s to .357 shooting 81 grains above 100fpe for a few shots. I'll settle for 60 fpe for more shots on a .22

[darkcharisma]

So i had some time to put the Gauntlet together again. this time i tested the shortened tube. i got 756fps with 28.6 (14.3x2pellets) grains at 1300psi. compared to the full discover tube 815fps at 1200psi. i cut off 1.78 inches or 0.9 inches off the plenum. i only have about 17-19cc left from 25cc. i am sure with the stock tube i can get 40fpe at 1300psi easily. so my claim was only 100 psi off on the full discovery tube. sadly thats part of getting older.
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actually. i turned the hammer preload some more until i could not pull the bolt back anymore. and i got 770fps with 28.6 grains. so i wans’t going senile. thats already 38fpe with a shortened tube.