Tuning Prod BStaley Mod Questions

[Bugman]

Hi all: New to Prod and working on a quiet pesting rig for shooting around a horse barn. I have a Tatsu on it so that helps, but I'm thinking about trying to flatten my curve a bit and get a good string of sub 600 fps which also seems to be the quietest. Most all the threads regarding the BStaley mod link it to drilling out the transfer port to gain more power, but since I would like to be sub 600 or mid 500 fps (CPHP 14.3, thus sub 10fpe) is that a necessity, or does the mod reduce your power that much and is recommended to go with it? Of course I don't want to waste air either so trying to be effcient. I did consider going regulated but with the Prod it seems it's not as beneficial as it is on the Mrod (which I also own as regulated). 

Currently I the hammer max CCW, and have a goofy speed dial spring preload installed as that came with it used, so accessing the hammer throw is a pain, but willing to go through the exercise. I think most of the reco's were around 1-1.5 turns CW on the hammer with 3 orings to start. So that's around my starting point. I may question going down this path if the port mod is needed as I don't have a backup in case of folly....

Thoughts?

 

[-Blue]

I have done the mod on 22xx bases and a disco, the pictures I attached to help explain the concept are from a 22xx.



I usually try to stack the o-rings so that they (+/-) contact the hammer face when the striker contacts the valve stem when the striker is fully recessed. My thinking is that in this configuration I can gain more adjustability by turning the striker out (from full in) to go from very little contact to more valve lift. One picture shows a full stack (on the 22xx valve) and one has one removed to show the valve stem.



I don’t think you necessarily need to do anything with the porting to start

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[BZO100]

I threw in a HUMA reg so that I can get more shots at high power. If you shoot low power, it probably isn’t worth your effort. AEAC on YouTube has a P-Rod review and he got a bunch of shots on factory power. Even though the HUMA took up a huge percentage of air tube space, it gave me 2-3 magazines of regulated shots around 750fps 16gr polymags (with a large transfer port).

 

[Bugman]

I threw in a HUMA reg so that I can get more shots at high power. If you shoot low power, it probably isn’t worth your effort. AEAC on YouTube has a P-Rod review and he got a bunch of shots on factory power. Even though the HUMA took up a huge percentage of air tube space, it gave me 2-3 magazines of regulated shots around 750fps 16gr polymags (with a large transfer port).

That's the dilemma for me as I don't want that first shot at a pest to be a question mark on accuracy. I'm going to try the mod today and see how it goes. I just want the first few shots from a likely fill from 2500psi to be spot on. Right now, 2500-3000 psi is unusable so perhaps the mod will help flatten and extend the psi range a bit. If it doesn't I may go the Huma route. I love the Mrod's Huma regulated shot consistency, but I'm trying a lighter weight platform with the Prod. 

 

[Vetmx]

You’re not asking too much from the gun so you’ll get it without a reg. When I had my Prod set around 600fps with 14.3’s, it was a very capable barn gun. I did have a HDD in it to help but it wasn’t totally necessary. You’ll get that first shot accuracy when you figure out your best fill pressure.

 

[Bugman]

I've been testing it the last hour or so with a 4 ring job and 1.25 hammer turns...Currently at ~525 fps with 14.3's and I'm getting close to 40 shots with good accuracy at 15 yds. If I pest to 25yd that's a long roof shot while most are closer 10-20 yds. Worth a pigeon test in the next few days. This should be around 9 fpe muzzle velocity so likely good enough for the job at hand, for now If I need more I'll up the hammer turns by a 1/4. 

 

[Vetmx]

If 25yrds is a long shot you are going to have some fun with that Prod. You are working right in its wheelhouse. 

 

[BigTinBoat]

I've been testing it the last hour or so with a 4 ring job and 1.25 hammer turns...Currently at ~525 fps with 14.3's and I'm getting close to 40 shots with good accuracy at 15 yds. If I pest to 25yd that's a long roof shot while most are closer 10-20 yds. Worth a pigeon test in the next few days. This should be around 9 fpe muzzle velocity so likely good enough for the job at hand, for now If I need more I'll up the hammer turns by a 1/4. 

That's not how to tune with BStaley. The HS is for setting the pressure range. The striker is for setting the velocity. If the buffer is the correct height then turning the strike in will increase your velocity. It's the opposite as tuning without the buffer)

 

[Bugman]

Perhaps, I stated that incorrectly? Was referring to hammer stroke for velocity. Spring is at 7 turns in and stroke at 1.25.

 

[BigTinBoat]

Perhaps, I stated that incorrectly? Was referring to hammer stroke for velocity. Spring is at 7 turns in and stroke at 1.25.

Ok, miscommunication. I usually use Hammer Spring and Striker (or Stroke)