All Springer/NP/PCP Air Gun Discussion General > Engineering- Research & Development

Design WIP

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Still have a fair bit of work to do on this; but figured I'd go ahead and post it up; so folks could throw in their input...
Or just enjoy watching it progress.  :)
But-started off a good year ago or better working on a .22 slugger ACP build idea-needed a lathe; and have been working on that-it's nearing completion, still a ways to go-but getting there... During that time; I've played with endless designs and concepts-but finally came up with two unique ideas that sparked my fancy-one waaay too complex for me to make; that I ended up submitting to a company for review-they're interested  ;D

And then there was this one-still a lot of design work to do; have run through probably 8-10 different variations getting some of the base geometries of the action worked out-but you single-shot fans should approve  ;)

Will add more screenshots as the design progresses... Currently; have not completely decided whether or not this will be an ACP; or just a plain PCP-depends on whether or not I can squeeze a decent pump mechanism in the stock-which would actually be one of the first things I'd make... Goal is 60 FPE with slugs from a 26".22 LR liner; depending on whether or not I use the 1020 DOM tube that I have; or get some 4130 CroMoly-there will be between approximately 90-115 CC of reservoir volume (3KSI) in the single tube in the butt-I could either add more tube top and bottom in the buttstock; or a pump on one side and more tube on another, or so on... The action links will become more apparent after I draw the block cam, and work out the c0cking linkage...
Will add more as I get things figured out  :D
Also will add my numbers for the valving and engineering of the tube; so folks can point out anything they think is really off...

For clarity; the receiver will be one piece-drilled from the front (and likely tapped/threaded) for the barrel and hammer tube; and a spigot turned on the back to form the valve body-which will be pinned with two 1/8" dowel pins in double shear-once I get a cross section view/3D model drawn; it will become easier to see what I'm talking about... The valve stem will lie flush with the face of the breechblock channel; a projection on the hammer will push it further in upon firing. One of the complications that took me some time to figure; was timing the block's fall with the c0cking of the hammer; to avoid interference... I've figured a way to plot a snail cam; that allows enough rotation in the first part of the c0cking stroke for the hammer to provide clearance-however I may still need to cut a relief channel into the breechblock for it to clear. Hammer stroke will be relatively short; as drawn the total movement afforded by the linkage is 1.1"; of which I'll need to reduce the hammer stroke by about .25" to account for hammer travel rearwards during the shot, and take-up of the hammer by the sear... But the mechanical advantage of the lever should keep things comfy.
The pressure tube is 1" OD; as drawn .76" ID 1020 DOM tube-may go with .083" wall 4130 CroMoly... 1/8" valve stem, thinned to .064" in the .25" throat-which gives me about 10% over bore-sized porting in the throat... the front face of the valve is counterbored to .5"; that gives me over 2x the throat area over the .304" poppet-I've made no provision for a valve spring; although I could extend the rear of the valve back enough to give a place to attach an offset spider to... The bore-sized transfer port is on the long side at 1.9" from the rear of the poppet to the face of the breech; and can be drilled from the valve end up to the breechblock-while I could match drill the breechblock straight through in-place; I'm hoping that I can use it to absorb any misalignment caused by wandering of the drill; by spotting both sides and drilling it out undersize; and nibbling it out the rest of the way with a Dremel tool...
The trigger assembly/c0cking links will be supported by a formed .25" bottom plate; inset into the receiver-exact orientation of the sear/trigger is one area I have to figure out yet-the stuff in the drawing is leftovers from a previous rendition...
I have a piece of 1/2" DOM tube that I will sheath the .22 LR liner in; which in  turn will be sheathed in a .75" OD DOM tube-planning on building in an integral shroud/silencer into the barrel assembly; by extending the outer sheath longer than the inner barrel assembly-my lathe has a big enough through-bore that I can step-turn a taper into the outermost sheath.
A bit jumbled (that tends to be how I think); but that wraps up most of the details that I have plotted now; short of the tube/pin engineering data; which I'll double-check and add later...

Nice project, I wish you all the best with it....  8)



--- Quote from: rsterne on April 16, 2022, 06:10:10 PM ---Nice project, I wish you all the best with it....  8)


--- End quote ---
Thanks Bob-this time I intend to finish it...

Cool design!

Fwiw, not sure if it has any bearing here, the original falling blocks used an ever so slight angle/wedge to the block. It was to help the block not drag the case as bad when dropping the block.

Also, the Leshiy uses a short stroke hammer with leverage. I think that approach will work perfect here as well.

Excited to see how this progresses.



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