Original spring is on top. Rebuild was pretty much a reversal of the first post. The spring got a razor thin coat of copper anti-seize. Painted it on the coils with a flux brush to get complete coverage. Then added two very thin hardened steel rotation washers to the base of the spring guide. Cocking linkage and the outside of the piston were burnished with moly. Went really light on everything in the hope that the velocity would climb into an acceptable realm. The gun was assembled and test fired about fifty times to burn off the excess lube in the compression chamber, then the barrel was cleaned and the gun set aside.
The barrel weight was missing the set screw at the breech end of things. The hole was also stripped. Looks like it was initially an M5 x .8mm thread.
I opened it up by running an M6 x 1.0mm tap through the hole.
Don't forget the cutting oil.
An M6 set screw is way too long.
Cut it down and slotted with a saw.
A bit of cold blue...
And it's pretty well blended in.
Went through my pile of inserts looking for a suitable annular element. A Feinwerkbau--or maybe it's a Weihrauch--4mm insert fit the bill. Much better for shooting at 10 meter targets.
Here is the high end of the chrony's tale. It's more than a few feet faster than I expected and very consistent. Gave the rifle back to Guy Sunday morning. He looked pretty happy.
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