One of the Crosman 622 in my collection was leaking and also had an indexing problem since the beginning. As for the other, it was very difficult to pierce a CO2 cartridge.
These are links to previous posts on CAF:
topic73457.html (repair - 15 August 2016)
topic75347.html (manual indexing magazine - 8 February 2017)
topic82946.html (Cartridge not piercing - 2 June 2019)
At the end of September 2022, when I discovered that the previously leaking 622 was leaking again I decided to have a repair session with both rifles.
I started with the one leaking and made a new valve stem / poppet from Delrin and 1/8 steel rod. The leaking was solved but the indexing was not working at all. In fact it was worst, because before it would index correctly once in a while but not this time.
I decided to also disassemble the other one as the piercing problem could have been an indication that the valve (which is anchored only by a single screw) has started to stretch. After disassembly, I could confirm that the screw hole was starting to be damaged. I also saw that there was no Hammer Tube Cover (622-050) meaning that the rifle I thought was pristine had already been opened by somebody else. I machined another cover in aluminum to replace the missing one and I also made another valve stem the same way as for the first 622.
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The solution to avoid further damage to the valve body was to pin the tube to the valve in 3 places and the slightly deformed screw hole was hammered back. Now this provides 4 anchors. During the repair process I noticed how the indexing should work and realized what was wrong with the other airgun that doesn’t index properly.
There is a boss acting as a stopper for the rear indexing pin and the previous owner had modified it. The original boss was ground down and a steel washer embedded in glue was added on top.
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Measurement on the intact boss was .150 inch and a brass pin was machined to fit in a hole drilled in the frame of the altered one. To avoid another disassembly, a lot of testing and filing followed. Without the springs installed I was manually activating the magazine with the indexing system until it seemed that the pellet opening was ending at the right spot. By then my boss was shaved to .130 inch. Unfortunately when reassembled and under spring tension the indexing problem was back exactly as it was before (the hole was pushed too far). This also meant that all the time spent on the fitting was useless and another disassembly (that I was wishing to avoid) was required.
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I made another pin exactly .150 inch, dropped it in place, reassembled the air rifle and Bingo! This time the indexing worked flawlessly.
I am not sure that all 622 rifles having an indexing problem would be the same as mine but it might be worthwhile to verify the height of the stopping boss.
R-Gun Pete