So I Tried Some Recommended 392 Mods
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So I Tried Some Recommended 392 Mods
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Topic: So I Tried Some Recommended 392 Mods (Read 1078 times))
bhh
Sharp Shooter
Posts: 803
yes
Real Name: bhh
So I Tried Some Recommended 392 Mods
«
on:
September 29, 2016, 01:43:19 PM »
Based on various advice here, I installed a weak check valve spring, machined a pocket around the transfer port and installed an o-ring, and made a connecting nut to lengthen the piston shaft and eliminate space between the valve/cup seal.
They work great! First two pumps are extremely easy and give me 425 fps with 14.3 gr CPHP pellets.
Eight pumps gives me 700 fps, and 13 pumps produces 800 fps with retained air. ( I know, it won't hold up to 13 pumps for long...)
So now I have a rifle I can plink with all day at two pumps, or crank it up and go hunting.
Only problem is now I want to pull it apart and keep tweaking. If you know what I mean....
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Southern Ohio
semperfalcon
Shooter
Posts: 21
yes
Real Name: Matt
Re: So I Tried Some Recommended 392 Mods
«
Reply #1 on:
September 29, 2016, 02:19:42 PM »
I'm in the same boat. My Armslist steal 392 is getting here today and I'm already planning to do the same mods you did and figuring out how much deeper I want to go into it. If you test out anything that nets some nice gains be sure to update this thread!
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NC
redlined_b16a
Expert
Posts: 1234
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Re: So I Tried Some Recommended 392 Mods
«
Reply #2 on:
November 25, 2016, 09:06:45 AM »
I modded my 392 to hold and dump 14 pumps.
Normal valve mods like done to a 13xx valve.porting and heavier hammer spring.
Custom lenthened pump linkage to push piston closer to valve.
No chrono but she was powerful.My .22 break barrel was chronied at 750fps with 14.3 cphps and the 392 was alot stronger than that.
Issue with that much pumping and pressures was the linkage sheared the stock pins.
I done extensive mods to beef it up.
Like using pins that are about 5/16" diameter vs the factory 3/16"
Currently my valve leaks so I'll order a new one and start over but this time not using 14 pumps.I want to kerp it aroind 12 pumps max.
Where I went wrong was machined the valve body to increase the space.Dont think it was needed.
I also added more screws to secure valve and drilledtransfer port larger.0.200" I think.Its been years.
However the guns performance increased greatly but the wear on parts did as well.
My hammer spring was very tight.Hard to pull bolt back.
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Louisiana
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So I Tried Some Recommended 392 Mods