Made an aluminum breech
My breech O-rings were worn so instead of just replacing them I decided to make a new breech lol. I machined this one out of 6061 instead of the factory delrin and made the tolerances tighter so it doesn’t flop around. I also grooved it for 3/32″ o-rings instead of the original 1/16″. I cut the grooves to the tolerances listed in the machinery’s handbook but I think I need to go back and loosen them up a bit as the cocking effort is a little bit too high right now but it won’t be a problem to fix. Looks cooler and no more wasted air out the breech.
I had a member ask me if I could make him a breech out of bronze, has anyone tried that? I’m thinking the breech will be so heavy it will absorb a lot of the hammers impact rather than transfer it to the t-hat. This aluminum one “feels” about the same as the delrin but I don’t have a gram scale.
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You also have to consider friction. If you add o-rings, the breech will not slide as easily on the barrel end and cause inconsistent valve opening.
That is why the oring on the barrel side fits looser than on the tophat. The tophat end moves with the tophat, the barrel end slides back and forth on the barrel.
You’d run out of room. On the tophat side your innermost o-ring wouldn’t actually touch the tophat. On the barrel side the innermost o-ring would run into the knob threads. Moving it further in than the threads would be very difficult as you’d have a super long thin grooving tool to get in that far. The tool would be super easy to break and probably leave a bad finish as it would chatter a lot.
On a separate matter, would there be any advantage by adding an extra o-ring grove to the ends of the breech (both hammer side and top hat side)
would it offer a better seal or just over kill?
Oooh, that sucks. One of those things you wouldn’t think about until you build it and try. Even if you could build one out of a material strong enough not to self destruct I don’t know how you’d overcome the POI shift.
Yeah if all goes well and you need a special configuration we can work something out. It wouldn’t be a problem adding a second #10-32 thread to the side to work as normal or to facilitate a future side lever mod.
MetalHead, I abandoned the side lever concept. It basically flung itself into peices using that heavy spring. It also was causing POI shifts, the lever was violently flopping about while the pellet was traveling down the barrel.
I am drawing up a knob that would make it easier on my thumb, so a standard config would be great. Maybe an additional hole 90 degrees to the original so I could convert to side-knob if I had to. Would want the knob on the right side of the gun, at the same distance back from the front of the breech as the original.
If your tests go well, consider one sold to me with the above config.
eric, nice breach
i am very interested in one of your shrouds if they are for sale please pm me for info and price
Riff, I chose a wear resistant grade that is supposed to be as durable bare, as 6 series Aluminum is hard anodized. I had to experiment with it a bit to find a suitable grade so understandably I don’t want to just go blurting out my findings. It is harder and has higher strength ratings than the 6061 I tried at first and quickly had problems with. I have one in my gun, and I’m sending one out ea. to 2 other testers who have the Blodvalve & heavy spring so they should put it through the paces pretty quickly. I’m thinking between the 3 of us it will be easier to spot any problems. If they work out good this would probably provide a good base for your side cocking lever. If you’d be interested in sharing your bolt pattern I could drill these to where they would work with your lever so people could have a bolt on mod.
Just curious, how durable is the aluminum you chose. Does it start to deform at all with the hammer impacts?
Having worked with aluminum tooling (mandrels for rolling carbon tube on) for the last 5 years, the only alu tooling that holds up has been anodized a very dark brown. Dunno what the color means, thats just how the best tooling comes back to us.
Keep an eye on the hammer end of your breech, measure it after some repeated shooting. If there is no swell in OD, Ill be interested in a breech from you.
I’m thinking $50 + shipping for the plain version shown, or $75 if you want it fluted like in my first pictures.
Not quite ready to start taking peoples money yet though….
$?
Sawtime / jslateiv, you guy’s have a PM.
Getting close fellas. I had some problems with binding like Pablouk mentioned on the first version I made out of 6061. I found a new grade of Aluminum and figured out the o-ring gland dimensions. Shot for a bit tonight and the binding issues seem to be solved so after a little more testing I may offer some up for sale for those who are interested.
TMI WOK. 😮
Have you used that stuff before? I’m always weary of the durability of the rattle can finishes.
I have used their Gun Kote finish and it is tough as nail.
Brownells stuff for guns is top notch stuff. They probably have a couple choices for you over there. Take a look at some of their videos on the finishes.
I know Alumahyde is not like a normal rattle can finish. It’s hard to sand off and is impervious to solvents.
TMI WOK. 😮
Have you used that stuff before? I’m always weary of the durability of the rattle can finishes.
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Hey riff…
What about a knob on both sides of the breech? That way it is balanced and u can use both thumbs to cock it with less effort!