Got some chrony numbers for the stretched P-Rod -

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SteveV

SteveV

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Feb 25, 2018
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With a M-Rod 20" 22 caliber barrel installed, stock hammer spring and x-fer port, was able to get her right at 20 fpe.

Hard to believe, but I didn't have a Disco hs on hand, so I stretched the stock hs, drilled our the x-fer port to 7/64, filled to approximatley 2900 psi, got these numbers -

Crosman 14.3 hp from the tin -

24 shots/3 mags

hi 869

low 840

avg 855

es 29

sd 10 

Was intent on doing a bottle mod to this gun, but as it stands, the reg point would need to be above 2k for the sweet spot, as the gun still had 2000 psi in her after 24 shots.

That string could hopefully be improved upon, and that is pretty decent power for a early season tree rat popper, so may have to think this one over a bit...

Anyone making power valves for the P-Rod?








 
Yeah, I'm thinking the same thing -

My first P-Rod was able to make almost that much power with just a Tim Hill x-fer port and a Disco hammer spring and the stock 12" barrel.

Need to get a for real Disco hammer spring, as I'm not sure if the streched P-Rod hammer spring is gonna hold up and not sag -

Or maybe I can just be patient and wait for Don Cothran to recover from his knee surgery? But then, that would require a reg, and might as well go the bottle route if a reg comes into play -



airgun things that make you go hhhmmm...

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We'll, have been told the Gauntlet drop block is the best one, as it has two retention screws per side. I have not tried to order one-

Archer Airguns sells one for the QB 79, same size tube as the P-Rod -

I learned of the two aforementioned drop blocks from other forum members.

I did not know of those options at the time I purchased drop blocks from JDS Airman. They are all three designed to work with 50mm od paintball tanks and regulators.

All three of these drop blocks will work on a P-Rod, QB, Crosman 1600, 22XX, all w/7/8" tubes.

Then it's just a matter of how much $ you want to put into the bottle and reg. Know what reg pressure you need to get the performance you desire.

I'm learning as I go, lots of folks smarter than me on this forum to learn from.


 
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You made me go look to see when I did something similar. Just about eight years ago. Time flys when you are having fun. Mrod Barrel on Prod



You can take the valve exhaust, TP, and barrel port to 0.120" - 0.140". A 22 mrod valve is 0.120". If you are going to regulate it, than go 0.160"
Click to expand...

Thank you breaux, much appreciated!

That's why I hang out here



EDIT: Don't know if I got lucky, but the barrel install was easy peasy. The hardest part was sourcing an oring for the barrel. Found posts on YouuTube stating the o-ring was a #9, one said it was a #10 - BS!!

Had to dig the one out of the P-Rod barrel and matched it up at a local plumbing supply and hardware. Have 4 spares lol - not going thru that again
 
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My latest drop block purchase was in fact the Archer version. I know I would feel better if the screw retention hole was set a little further back from the end of the tube.

And you're right, it wouldn't be that hard at all to tap it for two more retention screws. 

Been using P-Rod valve retention screws for my drop block builds, and let the head of the screw clear the hole in the tube, same way the valve retention screws mate to the valve.
 
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We'll, have been told the Gauntlet drop block is the best one, as it has two retention screws per side. I have not tried to order one-

Archer Airguns sells one for the QB 79, same size tube as the P-Rod -

I learned of the two aforementioned drop blocks from other forum members.

I did not know of those options at the time I purchased drop blocks from JDS Airman. They are all three designed to work with 50mm od paintball tanks and regulators.

All three of these drop blocks will work on a P-Rod, QB, Crosman 1600, 22XX, all w/7/8" tubes.

Then it's just a matter of how much $ you want to put into the bottle and reg. Know what reg pressure you need to get the performance you desire.

I'm learning as I go, lots of folks smarter than me on this forum to learn from.

Click to expand...

Steve, thank you very much for that info! Much appreciated.
 
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FWIW: I recently called Umarex about the Gauntlet drop block. While the price is great at $12.95, they haven't had any stock for months, and had no idea when they would. :( The Archer only has two screws, but probably could be mod'ed for four.
Click to expand...

Fuzzygrub, thank you! Gonna have to search around for one while waiting for Umarex to restock them.
 
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Not sure of the capacity of the tube extension, but if one had to guess, combined with the P-Rod tube, probably close to that of a Discovery.

And yes, it is very quiet. The barrel is shorter than the tube with the extension, and the shroud also contains some Jim Gaska baffles. Very quiet.

If one can deal with the look, you really don't need a shroud extension, as you can play with the position of the rear shroud bushing to extend the shroud further past the end of the barrel -
 
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Been using P-Rod valve retention screws for my drop block builds, and let the head of the screw clear the hole in the tube, same way the valve retention screws mate to the valve.
Click to expand...

Was that using the Archer block? I would have guessed metric screw threads like the Gauntlet.



FWIW: I found shifting the shroud forward was a good way to test for what length you needed, both cosmetically and sound effectiveness. It did tend to have shifting poi issues. Some thin closed cell foam in the barrel band can help. Rocker1 on GTA makes some reasonable prod shrouds to length.
 
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Haven't tried one, but for $25.00, probably will pretty soon.

You'll be iiinterested to know, the source of the leak was, believe it or not, the forward location trigger group screw - it was too long - it actually was pushing/digging into the valve with enough pressure that it scored the surface and removed some material. I think the valve wasn't sealing well at the bottom of the tube due to the pressure, and that would explain it leaking around the gauge? From the front of the valve?

ANYWAY - hope you are enjoying the Maximus!





Vines
 
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