The part modified is CR-018 which is called Receiver Rear Cover in the part's list. I ground it down on the hammer side, and currently have an additional 0.075" of travel, and should have same in gap. I still could go more, if needed. The threads are M10 X 1.0 and used a tap to chase them.The inner spring is a 5/16" OD X 2.5" long with 0.047" wire. It came from McMaster-Carr and indicates #24CP. I'll have to check if they are still available. https://www.mcmaster.com/9657K227/ Because it rides on the top of the adjuster, you do have to shorten it slightly. I ground the ends to do that.A couple of test fires with full gap, looked promising at 2200psi. A full string will have to wait until tomorrow.
John, Do you have a parts break-out for the Akela? I'd like to order a couple springs from Crosman to experiment with so I don't have to mess with the original. I have the .177, so the part number might be a little different from what you ordered. Thanks...
Still following and wondering how the .25 turned out as far as fps and accuracy. Did you use a twin spring in that also?
Unfortunately, as Paul has confirmed, getting to this part is a bear. There is some epoxy to overcome. It was also discussed in the video. At some point, I will go into the 25 Akela. My first thought was just to remove it. But now, suspecting that will leave me with a peaky curve. Maybe it would be better just to make the chamber larger?