The QB78 Target Stock was not too bad to modify for the Disco. The hardest part was patching the stock where the original stock bolt was as it partially in the same area as the Disco's gauge hole was going to go. So when I cut the area out of the butt section to make it very much different from most stock I was able to use that piece of wood to cut a plug to fill the original bolt hole. Other than that it was just a matter of opening up the action area to 5/8" so the Disco action could slide in. Everything was pretty much straight forward.
The valve was a complete new valve that is very different. The gauge was removed from the factory tube and installed in the new Double Tube. This was done to add a little extra length to the Double Tube and remove it from behind the valve removing the air restriction is causes. Now the new valve was made longer to cover the gauge hole in the factory tube and seeing there was no gauge there that area was opened up as far as possible. This gave a much better flow of air which my Carbine was going to need. The front end of the valve was also modified to permit better air flow and the transfer sleeve and port was enlarged as much as possible. The new valve was drilled to accept a #10 bolt in place of the #8 and the bolts were rated at a much higher strength. This permitted a much higher fill pressure, 2600 PSI is not an issue and I could go to 2800 PSI without any problem. The hammer was modified in a couple ways that also helped. One being a stroke adjustment rod was added so now the Carbine not only has a power adjuster but a stroke adjuster. We were going to add a needle valve in the valve discharge but decided not to as I knew I wanted as much air as I could get. I did have one string that was in the mid 60 FPE but I did not get as many shots as I wanted so I tuned things down for now. I will be going back and try to tune it to get 16 shots with an average of the mid 60's FPE. Will need t play with springs and stoke adjustment to manage that. I'm using 31.02 Barracudas & Kodiaks and I am down to about 50 pellets and everyone is out of stock on them. PA just got the Kodiaks in and I have a 1000 coming in so I will be able to tune my Little Carbine to where I want it and then start to see how it groups. This being out of stock on .25 caliber pellets did create a small problem with getting things done.
I wanted something different that no one would have and I think I got it!
BTW My Carbine would never have had the power and shot count if it was not for the Disco Double Tube
Checkout my website discosrus.net
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