Rubber Hammer Stop.

[Mike71]

I've seen a few things for the CO2 guns like o-rings and such for bolt bounce.
But this being for a pumper (362).
Thoughts are with the hammer pin banging hard on the back of the bolt over and over, I've ordered a hammer with screw in pins to help.
But wanted to try a rubber bushing that can stay in place at the back of the valve, find the right thickness to softly stop or significantly slow it down so the pin doesn't slam full force into the bolt..
I've Googled and searched and haven't found just what I'm looking for..
I know someone has to have messed around with this.. what has been done and what has been learned/found works ?
Or does it not matter ?

[Psipumper]

Dry firing will cause the pin problem, especially after adding stronger hammer spring.
I always use at least four pumps.
Not sure what the owners manual says .

[Mike71]

And yet it's all over that "it's fine to dry fire"...

I am now using the factory hammer spring and lighter valve spring after destroying one pin and messing up another.

But still thinking about a rubber bushing/bumper.. I'll make one out of wood to get the size right, then softer rubber, see if it still fires full power.

[Psipumper]

All by design or lack of. Ideally the hammer should bottom out on the valve at the same time as the hammer pin hits the bolt and slot in the tube.
The hammer travels further when dry firing and travels a little less with each pump due to pressure in the valve increasing . Up to the point where the pressure resists enough to retain air at some number of pumps.
You could build a spacer to have the hammer face bottom out on the valve instead of the pin .
The hammer I built is ok to dry fire because it is built as described.


Charles

[Mike71]

Getting closer lol.
I still think a bit of cushion would be good vs a solid metal to metal stop.. even a softer plastic.
I do like what you did.. nice work.

[Mike71]

Best bet would be an old school 1322 cocking setup.. leave the bolt action breech and bolt, but no hammer pin at all. But would be a problem with the 362's stock..

[Spooner]

Mike... this is what Ron (Tack Driver 10) came up with and I have his in my 362, the 367, and both 13xx builds. I do not remember what the exact dimensions were? The only thing that I had to do was install it with the valve installed/secured, mark a spot on it through the breech set screw hole, remove it and drill out a relief hole (not all the way through the spacer though, just enough) for the breech set screw to seat in far enough to secure the breech. I also had to put a flat spot to clear the valve rear flange.



It only takes a small amount of travel of the valve stem inward to release the pressure and these work fantastic in my builds. 

I have one spare left. If you think this will solve your problem... PM me and I will send it to you. 

[Mike71]

Let me test this out first, trimmed down (way down) a sway bar bushing.. waiting on a replacement pin as I have no idea how long it will take to get the one from Alliance Hobby.

It slides in but stays in place as it's a snug fit.

[Blowpipe Sam]

Folowing.

[Mike71]

Ok, after some work I got it down.. now this works in My 362.. May be off on others so take that as it is. This is also redneck work at its best, it's all I got to work with on this kind of stuff. Take this and get someone to lathe some out if you like.
I have some extras if someone wanted to try one out.
I did have to add a heaver hammer spring to get it to empty 10 pumps, but it's a bit heavy (.040) and will dump 12 pumps, may try a .038 spring. It won't touch the bolt in a factory plasticbreech, I'll see how it does in the steel breech when I get it.
Nice and muffled thud dry firing it.

[Spooner]

Not a thing wrong with redneck ingenuity  . It works, and that's all that matters  .

Your initial retained air may have been due to hammer bounce back from the rubber material. If you have the minimum amount of stem travel needed to release the pressure with your bushing, it is possible but sounds like you solved that with the heavier spring. 

With Alliance Hobby... depends. Nick does not do individual order shipping. He waits until he has a batch of things to ship then sends them all at once. Generally, about 1-2 weeks.