Wednesday, September 28, 2011

Some Notes On Reassembling the Crosman 500

So the handle on the BB magazine follower broke off when I was futzing with the gun.
So I drilled and reamed.
And pressed a 1/16” dowel pin in with a drop of superglue.
It works. I might shrink some small diameter heat shrink on it, not sure.
I made a seal for the valve, cleaned and reassembled the valve.
The biggest problem was that the barrel shroud wasn’t lining up correctly with this boss that’s part of the frame casting.
And the boss is somewhat mushed from having the shroud forced against it by the previous owner.
With the barrel and BB magazine inserted into the valve I found that the barrel wasn’t going in to the same depth as the magazine.
As you can see here. The muzzle cap has two holes of the same depth so I assume they should be the same.
The culprit seems to be that the barrel end is flared. I don’t know if that was done by the factory or by the owner. I suspect the barrel isn’t original. In any case it has to go.
So I inserted a transfer punch that was a slip fit and hammered out the dent.
And trued up the end, so that now the barrel and magazine are the same length.
And the shroud magically fits over the boss in the casting (I cleaned it up with files as well.)
The hammer spring (?) position was completely wrong when I disassembled the gun. This tells me that at least one person definitely was in here monkeying. It also shows why you need to take lots of digital pictures when you disassemble airguns. Through trial and error I found this is probably the correct position.
I’m not sure why the spring has that bent leg.
One more view for the sake of all who delve into these things.
The forestock was missing the square nut and screw. I used a #10-32 which isn’t original but I don’t really care. It works.
After reassembly I found the trigger was sticking – you can see scuff marks where it was binding against the slot in the receiver. So I massaged it to where it doesn’t bind and lubed a bit more.

The rifle works! It is actually fun to shoot and not as inaccurate as some BB guns. Semi auto can plinking is a treat.

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