392 Air Retention, why?

[3crows]

So an update, success at last and a few starlings are reported MIA back at starling HQ.

I went back to Ace and found a few different springs to replace the hammer spring. The one I found was .25 inch longer than the OE spring and slightly heavier wire also. I installed this spring with a thin aluminum preload washer into the hammer but it was too much and would off seat the poppet spring and thus not allowing the bolt to close or to engage the hammer lugs. I removed the spring and cut one coil from it so that now it was the same length or slightly proud of the OE spring and I kept the aluminum washer in the hammer. Reassembled the trigger group to the rifle and success, full dump at 8 pumps with even the heavier 17.3 grain Ruger pellets (which seem accurate BTW). The bolt cycles, the hammer requires more pull to cock but not overly so.

So, the assembly for the valve internal is now the two spring mod for the valve using the 10S washer to separate the chamber for the pump side valve and the poppet side valve. A weak spring is on the pump side and a stronger spring on the hammer poppet side. The total length of the two springs is approximately the same as the original single spring. I also have the -113 O-ring instead of the -112. The result is easier pumping at least through 5 pumps and full dump at 8 pumps even with heavier pellets.

My chrono is not functional so I cannot get velocity but there is no reason for me to think that 8 pumps is not 8 pumps, lol. It shoots hard and whacked the starlings quite decently. And it is grouping tightly at 20 to 25 yards, a ragged hole at 20 on several targets with the 2X scout scope.

[avator]

Congrats.
Let me just add this...
I've had a couple Crosman/Benjamin pumpers retain air. In many cases I simply pulled the conical/main valve spring out and gave it a squeeze in the vice until coil bound. Held it there for 10 seconds or so then reinstalled it..... BOOYA !

[Habanero69er]

Good news James! Glad to hear you got good results.

[3crows]

Congrats.
Let me just add this...
I've had a couple Crosman/Benjamin pumpers retain air. In many cases I simply pulled the conical/main valve spring out and gave it a squeeze in the vice until coil bound. Held it there for 10 seconds or so then reinstalled it..... BOOYA !

Thanks guys, that probably would have been easier! Well, if my modifications go south I will revert back to your solution and give it a try. I wanted to try to reduce pumping effort and it is now noticeably easier. I would rarely use more than 4 or 5 pumps for plinking and now that is easy, getting to 8 though still needs a little sincerity.

One thing I did notice, it seemed like in that thread linked earlier that one of the gents was removing the pump lever roll pins to get access to the valve, if so, that is not needed. One quick pump and it will shoot out the rear of the pump tube.

Thanks again to all,
James

[3crows]

I got the hammer springs in today from McMaster-Carr, the part suggested earlier. They appear to be about right in wire diameter and length. Very similar to what I found at Ace that I had to cut shorter, the new springs will not need to be cut. I hate to take it apart but getting to the hammer spring is easy, so, ----.

Thanks again,
James