20 cal Prod

[Tack Driver 10]

Picked up an 18" 20 cal Air Force barrel and fit it to the Prod breech.
Used a 17 cal bolt sleeved to .20".
The barrel thins to 5/16" at the breech end.
Made a sleeve with the TP and lead.
2X Carm mags in 20 cal.

Using the lower end from my Prod test gun.
Regulated with a HUMA regulator.

Work in progress......

[YEMX]

Too cool!!

[longislandhunter]

Very cool indeed 

Jeff

[OTmachine]

I like seeing well thought out and implemented work, like yours!  Thanks for posting!

[tennx]

👍👍……

[ranchibi]

Very cool and a perfect platform for .20 in my humble opinion! Looking forward to you finishing this awesome project 👍

[Tack Driver 10]

The word on the street is......
"Regulating a Prod is folly due to the small 66cc reservoir."

There's a certain amount of truth to that.
The limiting factors are a short 12" barrel and congested tube.

Bypassed the gauge and made a custom valve extension freeing up volume.
The plenum gauge is mounted directly into the valve.
The reservoir is 50cc leaving about 15cc for the plenum.
The regulator is set at 1300 psi.

Hammer is 42 grams with a SSH rear cocker.
Brass core with a peek shell.

[eeler1]

Not familiar with the mag ‘carm’?  Otherwise, very cool. I converted an mrod to 20 cal for FT, using HW barrel , crazy accurate.

[Back_Roads]

Following, have a AF Escape .20 can run regulated or full throttle, fun caliber for sure.

[Tack Driver 10]

I really like 20 cal and also find it very accurate.
I have 2 AF 20 cal barrels which are made by LW.
They were discounted for years at 50% off.
These were $75 each but now are $185 apiece.

Both 20 cal guns will do MOA with JSB pellets.
Mounted the other barrel on my 20 cal Rat Rod.
It's a 362 pumper tube with a 9ci bottle.

Should get to chrony the gun later today, weather permitting.

[tennx]

Not familiar with the mag ‘carm’?  Otherwise, very cool. I converted an mrod to 20 cal for FT, using HW barrel , crazy accurate.

https://www.carm-magazines.com/carm-magazines.aspx

[Tack Driver 10]

Ran the Prod over the chrony with JSB 13.73 pellets.
Hammer throw .600", SSH gap .050".
Average 738 FPS, 16.62 FPE using about 45 psi per shot.
With a full charge of 3K psi should get 44 shots at this level.

ES is too high at 31 so lowered the reg from 1300 to 1150 psi.
Puts it in middle of the current unregulated bell curve.
Will retest in a few days when it warms up a bit.

My hat's off to Triggertreat for his most excellent spreadsheet.

[aluminumfetish]

The third picture down in the post with all the valve pics... what is the material at the poppet end of the valve ? Is it a 3D printer hammer stop / bstatley mod ? If so, how does it hold up to the impact of the hammer ? Nice looking project, I love my AF .20 more than all my other rifles. I don't know if .20's have anything special about them, but it's a cool caliber and even cooler that it's a bit odd.

[Tack Driver 10]

The third picture down in the post with all the valve pics... what is the material at the poppet end of the valve ? Is it a 3D printer hammer stop / bstatley mod ? If so, how does it hold up to the impact of the hammer ? Nice looking project, I love my AF .20 more than all my other rifles. I don't know if .20's have anything special about them, but it's a cool caliber and even cooler that it's a bit odd.

The bumper is 95A duro polyurethane rod, very tough and durable.
Cut to .050" shorter than the stem protrusion.
Back off the striker until power starts to drop then back in 1/4 turn.
Helps minimize hammer bounce at low regulator pressure.
Can also dry fire the gun without damaging the poppet. 

[aluminumfetish]

Like skateboard wheels ... awesome.  The old OJ 95a wheels were/are poly at about 95-101 duro and it is indeed very tough. I love the work you've done here.. that is an impressive rig you've made !~

[Old_School]

Nice work, Tack Driver! Have always liked the .20 cal...picked up an HW Carbine bbl to put on an old Beeman R9 I need to rebuild. Had converted an old R1 to .20 about 25 years ago using a chopped (12") HW bbl. It was a fantastic shooter and I often regret getting rid of it. 

Keep us posted!

[sam23]

Cool project. Question on the prod valves though, are they the same od as Disco valves/ compatible with Disco tubes with minimal mods.

[Tack Driver 10]

Cool project. Question on the prod valves though, are they the same od as Disco valves/ compatible with Disco tubes with minimal mods.

The Prod valve is the same diameter.
The mounting screw holes on the Disco are inline with the TP.
The Prod valve holes are set back about .325".
You'd have to drill and tap new holes in the Prod valve.

[sam23]

Cool, thank you for the information. 🙂