Hammer, brass bushing and valve pin wear
Grabbed a few images from my Vulcan 22 during its early break-in.
You can already see how the parts wear even early on.
The valve pin is developing a flat spot where the hammer strikes it. I expect this will expand until it reaches stable condition.
I wouldn’t be surprised if this is part of the early shifts in energy output.
Tip of the hammer looks like it includes an insert. I suspect this is a harder material than the rest of the hammer.
There is an odd pit at one point of the tip shoulder.
The brass bushing in the 0.22 is used to create a free floating hammer strike. It stops the spring’s forward motion
when the bushing hits the breach housing. Then the hammer flies forward freely. This debounces the hammer strike
to improve air efficiency. (Apparently this isn’t done on the larger caliber version(
However, the bushing takes a horrible beating and makes noise. If you look on the forum, there are reports of
a brass bushing that fractured and others with visible brass shards in the hammer chamber after a few hundred
rounds. I like that we can have a free floating hammer, but this promises to be a point of failure.
My gun has only about 100 rounds through it and already there is visible wear along the periphery
of the brass bushing.
Also galling where the spring engages the brass bushing.
I don’t have a Delrin replacement, but have instead encased the entire bushing in a rubber bumper. It reduces the
noise, cushions agains the impact and should help with keeping the part from wearing. We’ll see how
long the bumper lasts. I think an acrylic panel to allow continuous inspection is this weekend’s project.
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Well what are you waiting for?? Git- er- done…..
The rubber piston seal of a 10 ml Becton Dickson syringe is just the right size to cover the brass bushing.
Pull the piston out of the syringe and pop off the black rubber seal.
Notice the shape of the plastic piston end? It is just like the flange of the brass bushing.
This is the rubber seal. It has a molded recess into which the brass bushing’s flange will fit.
Leather punch a hole in the center of the cap just a little smaller than the hammer shaft.
Once you stretch the cap over the bushing flange, the hole will be a bit bigger.
Make sure the hammer can slide easily through your hole.
Of course, orient the cap so it is in front of the bushing (the side away from the spring).
Now the rubber cap takes the hit instead of a direct metal metal impact.
I don’t know yet how long the cap lasts, but it will be easy to replace when worn out.
NB: you probably will only have room to fit ONE grommet on the hammer spring if you add this cap.
Two grommets and the assembly is hard to fit back into position.
Interesting to say the least.
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Good observations and plan guykuo 💡
I made a lexan window sideplate for mine and it only took a few days :rofl:
It’ll look better when I get ambitious enough to do version 1.01.