Stands at the edge of the "Darkside" and asks ........

[Macky]

  Can I play with you guys ? I brought my new (to me) Woods Walker P-Rod........

  Got a good deal on a used LNIB WW P-Rod, pump, scope and pellets. Just took delivery of it a few hours ago. It came fully gassed too  Anyways, set up the chrony for some initial testing with JSB Jumbo 15.89g. From 2900 to 1900 got about 40 or so shots. Out of 30 shots recorded High was 620, Low 521, Avg 587, ES 99. I had some troubles with the mags only cycling 7 rounds, probably should read how to properly load them, but was way too excited to shoot it.

  After I removed the fill cap, there appears to be corrosion on the foster fill fitting, should I be worried about what's possibly inside the air reservoir ?

[daveb50]

Nice looking Woods Walker P-Rod you got there. I can't help with the corrosion issue though, as I'm new to the Darkside myself.

[Aussie]

Macky,

It is quite likely that there's some corrosion inside the tube too, especially if it's been fitted with a vinyl tube depinger.

next time you shoot it down to 1900, degas the tube, remove the fill valve end and have a peek.

If it's not too bad, give it a thorough clean with some white spirits, then a light touch of silicone grease on the corroded spots.  wipe off the grease so that there's just a hint of a smear left.  I use cloth wrapped around a wooden dowel to clean and lube inside the air cylinder.

[FuzzyGrub]

I've had some Mrod mags do that, and just move the spring tab to the next hole. 

See: http://www.gatewaytoairguns.org/GTA/index.php?topic=38058.0

[Ribbonstone]

Can awlays check the inside of the tube.

Make sure the tube is empty of ALL air pressure...and i mean ZERO.  Can check thatby dry fire until you feeel.hear no air at the muzzle, THEN hold the trigger back and run a rod into the rear end cap. If you can feel the striker compressing the valve stem as you push in that rod, it's empty.

Take off the shroud so you can really get to the fill nipple/end cap (the barrel is shorter than the air tube, so you it won't be in the way). 

Put a wrench on the flats of the fill nipple and unscrew.  If you are LUCKY, the whole end cap will unscrew and you can see inside the ai tube.  If you are unlucky, just the fill nipple will unscrew and you'll have to fight the end cap off (it's thin, but you can get it off by (1) a small stap wrench or (2) SOFT lead blocks and a vice).

[Macky]

daveb50 : Thanks for your comments, and how about we learn together !

FuzzyGrub : I was totally loading the mags wrong. Got it now. Thanks for posting markasaurus's link here !!!

Ribbonstone & Aussie : Thank you also for your posts, and info on degassing and checking the internals of the air tube. I got REAL lucky, as what is not apparent in my photo of the corroded foster fitting, is the fact that the main part that threads into the air tube, has flats on it. Came out no problem. The internals look fine to me, no corrosion. I reassembled as is, due to lack of silicone grease. This gun didn't appear to ever been disassembled before, there was plenty of lube and residual oils on everything.

  After putting everything back together, I hooked up the Benji pump and began the recharge process from zero. All went well, but noticed a very bad finish and serious pitting on the lowest part of the pump tube. How far down does that O-ring go, is this going to be an issue ?

[Ribbonstone]

About the only thing you can do for the pump tube is to clean it and lube it lightly with silicon grease.  HAve noticed pump tubes can get that pitting, the process I do not know.  But as the first o0ring has to ride over that area, woul make sure it is a bit smoother and litely lubed (or it's going to chew the o-ring pretty fast).

The only rust I found in a PCP tube (so far) was in one rifle (different brand) that I opened up a couple of days after it arrived, so evidently it was "factory rust".

[FuzzyGrub]

I had similiar corrosion on a pump I recently rebuilt.  It was the same sleave, but at the top.  I suspect that water gets behind the o-ring, and after a good period of non-use, the corrosion forms.   I sanded with 600 paper, and was able to buff allot out, and elliminate "catching" edges.  So far, it has been holding, but it has only been a week.  A couple of refills on the mrods, and probably 10 refills of the prod. 

[Macky]

Thanks guys regarding the pump issue. I will do some polishing, but got to get some proper lube for it, soon.

  Here is today's shot string. Forgive me if the graph is lack luster, I sorta just now learned on the fly, how to do that. It's not entirely accurate as the chrony did not record about 10 shots through out the sting. I should have kept better track of each shot, but basically wanted to know roughly where the sweet spot was.  I checked the factory settings, or at least the way the gun came to me, and here is what I have: Backed out (ccw) the preload 5.5 turns until it stopped, so 5.5 cw for preload. I could not turn the stroke out anymore ccw, seemed rather snug, but could turn it cw, so Zero for stroke. Did I do that right ?

  34 (recorded, more like 40 total) shots from 2900 to 1400, Hi 631, Low 540, Avg 596, ES 91 with JSB Jumbo 15.89g

[FuzzyGrub]

I am not sure of what your goals are, but with the bstaley 0-ring mod and a 0.110" transfer port, you can get 16FPE ave over 24 shots, with a low ES 20-25. 

PS: I haven't ran with those settings or that weight pellet, but offhand looks like a "normal" prod spread.

[Macky]

I am not sure of what your goals are, but with the bstaley 0-ring mod and a 0.110" transfer port, you can get 16FPE ave over 24 shots, with a low ES 20-25. 

PS: I haven't ran with those settings or that weight pellet, but offhand looks like a "normal" prod spread.

  Reassuring to know that this used p-rod is shooting typical numbers. 16-18 fpe would be ideal, but hinges on accuracy. Do cphp's shoot we'll in the p-rod? I may pick up a tin as they are fairly cheep, and use them for initial testing. I'll have to look into the bstaley mod and what I need for parts. Also I haven't looked at an exploded view yet, does the transfer port mod require drilling out, or is there a separate piece that can be made or purchased?

[FuzzyGrub]

The bstaley mod is just 3-4 o-rings.  Lots of info out there.  If you need links, let me know.

You can drill out your transfer port, or buy one from Marmit Militia for less than $9. 

Pellets: Might want to ask the previous owner which were best.  CPHP were not that good for mine.  H&N FTT 5.53 worked well. 

[Macky]

Found a link for the original bstaley oring mod, found a printed p-rod diagram too. Do some more tuning over the weekend.

[Macky]

The bstaley mod is just 3-4 o-rings.  Lots of info out there.  If you need links, let me know.

You can drill out your transfer port, or buy one from Marmit Militia for less than $9. 

Pellets: Might want to ask the previous owner which were best.  CPHP were not that good for mine.  H&N FTT 5.53 worked well.

   Previous owner said he only shot a few hundred rounds, so really no help there. I have shot that in just a few days. The package came with a tin of H&N Hunter Extreme's(5.5), tin of 16g Polymags, as well as 3 tins of JSB 15.9's. My Dad has a Gamo SSW in .22, he has some JSB Monsters, as well as CPHP's, and RWS Superdomes (I think) so I will try them all and report back here.

  Cheers, Jerry

[Macky]

  I got a chance today to shoot one good 24 shot string over the chrony. Fill pressure was 2600, shot down to 1600. Preload was at 5.5 and stroke was backed off ccw all the way.  I feel though, after looking at the recent numbers, I could have upped the fill pressure  to probably 2700-2800. I was quite surprised the curve was as flat as it was. I didn't get a chance to test for accuracy yet, so that will be another post.

  I hope the attached graph is a little better then the last one, I am still learning how to do that. As for the odd pressure numbers, I took whole 200 psi readings, and then averaged the in between's.

  Tonight, I did the BStaley O-Ring Mod (three #113 o-rings), as well as the poly transfer port. Unfortunately, I don't have proper lighting for indoor chrony work. Trust me.... I tried to get at least a couple numbers, but the chrony, just wasn't reading anything. I can say just by the sound..... It's going to be shooting faster.

  Oh yea, I am still shooting those JSB 15.9's

  More testing to follow.  Macky

[FuzzyGrub]

Looks very flat. 

[Macky]

  So I did a Bstaley O-Ring Mod, and poly transfer port. Too dark last night to get chrony numbers. So this morning, I took a couple shots, they were in the 730 range. I attempted to make an adjustment to the spring preload, and as soon as I did, realized I had gone too far. I ran out out threads, trying for MORE preload. It would not thread back in. Rather then force it, I dis-assembled the gun again, and fixed the issue. All back together, I aired up to 2900. I shot a couple dry fires to make sure the valve was opening, and made an adjustment. Loaded up 3 mags and started to shoot over the chrony. Well, I emptied those, reloaded 3 more mags and continued my testing. I finished up at 1200 psi with total 50 shots.

  What I am trying to accomplish is good power with a decent shot count ( lol like everyone else right). Once again, seems my power is in the 2000-1600 psi range.  It does not seem to like higher pressures, at least using the stock spring. I think the 730's I was getting was max preload. Perhaps going to 2 o-rings might help, giving the hammer more room to move.

  I think it took me longer to put this spreadsheet together then it did to shoot all fifty shots, including the unexpected tear down.

[FuzzyGrub]

Try adjusting your throw before removing an oring.  Go 6.5 - 7 on preload.  I use 1 brass washer plus three o-rings, which gives a stack height near 3 1/2 orings.  With 2 orings, it will only provide only a little buffer if the valve stem is near the max stroke. 

Did you do a tissue test to make sure the poly port is not leaking? 

[Macky]

Try adjusting your throw before removing an oring.  Go 6.5 - 7 on preload.  I use 1 brass washer plus three o-rings, which gives a stack height near 3 1/2 orings.  With 2 orings, it will only provide only a little buffer if the valve stem is near the max stroke. 

Did you do a tissue test to make sure the poly port is not leaking?

  OK, did not think to do a tissue test.  Assuming the leak would be between the breech and air tube, would I lay the tissue over each side ? I did cut the poly maybe a 1/16" longer then stock TP. I just may have a leak there, as just before emergency tear down I was getting 730's @ 2000 psi.

  The first two shots of the string, I made a couple adjustments. I thought 388 was quite slow, and warranted an immediate adjustment. The rest of the string, the throw was at max (fully ccw), and the preload was at 6. I can see more preload will help, but there is not much left. Maybe a 1.5 turns at best. I will try a lower fill pressure, in and around the current sweetspot, with the above mentioned adjustments.

  Thanks, Fuzzy

[JerryW]

I agree with Fuzzy on the o-rings. Leave all three in there or they won't accomplish their purpose of stopping hammer bounce at lower pressure. When you do the Bstaley mod, the adjustments don't work the same as normal. First you want to set the spring preload to give you a curve at the desired peak(clockwise on preload raises the peak psi). Then you can start turning the hammer stroke to adjust velocity(clockwise increases velocity). Note that the velocity adjustment is very touchy - make those adjustments in 1/8 turn increments. I found the adjustment range to be from 0 turns to about 3 turns clockwise. More than that and velocity plateaued and then started decreasing again.

My Prod was the same as yours - couldn't get the peak above ~2000psi with the stock spring. After installing a heavier spring, I was able to set my peak anywhere up to 3000psi. It works well when set to ~2500psi. Fill to 2800 and shoot down to 2100. I get about 15 shots with H&N FTT 14.6's averaging 780fps(19+fpe).

Shooting those strings can be very addictive. Enjoy the ride.

Jerry