Tune the PP800, need advise for power

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Savagefox

Savagefox

Member
Sep 7, 2018
115
67
Spain, Spain
I got the PP800, but unfortunatelly it starts loosing air trough the valve after the first shots... bad valve I supose, has send back to fix.



I never do any mods before, but I have a 3d printer and some experience making mechanical pieces and poop, so for the estetics I want to give it a ''semi-auto'' feel, replacing the ugly and big wooden grip for some nice and small grip placed forward to get a better balance and give the gun a rear ''talon''. I'm gonna need to make another trigger and place it forward, maybe just to push the real one, or I may change the internals to some degree.

For precision I think it may help if I just print a piece that holds the barrel together with the cylinder to avoid posible vibrations, I see some people doing similar with DIY pieces.

I can figure aestetics my myself, buy I never do any ''power tune'' before.



For the power I plan to drill a bigger hole all the way from the botom of the cylinder (Bottom part in contact with transfer port) transfer port and and upper canon hole that is in contact with the transfer port... Is that the way its done? What diameter should I use (caliber of the gun is .177)

I also read that someone has reduced the back end of the piece that holds the valve, so the hammer can push it a little further, but the autor don't recommend it, as just gained a 90fps or so and reduce the shot count considerably.

What if I put a stronger spring?

In other tread, the user be4meliz says that his PP800 .177 delivers 20 joules (900 fps 8.5g) without modification... but the manufacturar claim a lot less... did he got the exception, or every PP800 do the same? cause if it does that, I'm already near the legal limit of my country and better not touch anything.
 
PP800 tuning for higher power has 2 option, you can put a stronger hammer spring to have more power or open up the transfer port more to have more exhaust air, or you can even combine the 2 together. My preference is lighter cocking effort.
Click to expand...


Nice, I think the transfer port has de same diameter of the down and upper holes wich is placed (cilinder and barrel), do I need to drill these too?
 
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Here's the thing.... The transfer port bore in an unregulated gun has an effect of regulating flow to a small or large degree. Depending on port size. Ideally we would want the port to be the same size as the bore (but elongated like an oval where pellets slide over so they don't hang or fall in.) problem with that is because it is unregulated, the power will fall off steadily. With no smaller port to have a restricting, regulatory effect. 



The problem with a regulator in this gun is there is hardly any room to install one.



Good news. The barrel has no choke, and as such, is not picky about velocity to get good shot groups. 

My recommendation. The gun has a LOT of power in .177. I recommend radiusing the ports (smooth turns and transitions) but leave them the same diameter. Then detune the hammer spring, I even reduced my hammer weight. To get a flatter power curve. But less power overall. And more shots. 

My 177 is regulated to 650fps, but has the regulator plenum deleted. 36cc air capacity. Was 22cc with the plenum. As I'm sure you know, the plenum provides more air volume of regulated charge. For more power. With the plenum my power topped out at 760fps down from 850 unregulated. But I get 52 shots dead on 650fps and quite a few more steadily tapering down 

Now if all you want is power, then bore the ports to 4.5mm, and get some shims/weights or a heavier spring for the hammer. But your power curve will be abysmal. As will the shot count.



Now, I do have a 25 caliber that has been power tuned. But I backed the tune off to flatten the curve out, and increase shot count/quiet the gun down. Peaks at 28fpe 680-620fps for 8 shots. Was making 30fpe prior, but was wasting a lot of air, and velocity dropped a lot faster

Also, polishing the barrel does not add power. Unless you're just polishing it way too much and were shooting oversized pellets. The maybe. But a smoother surface means more surface area of contact. Which means more friction. You probably won't notice any power change with a proper bore polish. But I wouldn't be surprised if power dropped a hair 
 
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Pulled mine apart & agree with Long_gun- its oversprung- damn spring is longer & heavier than the one on my Gauntlet-+ added 3 o-rings inside hammer as an improvised debounce system which did flatten shot string. In my mind hitting an avg. of 700 fps would be ideal(we all have the need for speed but to me accuracy & shot count is more important. Have Huma coming & between that and lighter HS figure I will hit my goal.Now just need to get to ACE & try & find various springs that will match but lighter.Would avoid enlarging TP other than beveling as Long_Gun mentioned-If you screw it up, your done! And for so little capacity, your better getting a short blast of air Think of a water hose- it flows at set rate-pinch it & get MORE pressure; make it bigger at end & pressure drops.My good buddy started out tuning Mrods & explain this to me: mrod has meter screw that chokes off(to some degree) the TP & he said that closing it down actually gets it to produce higher shot count @ same speed as wide open. 
 
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1582754884_13995189565e56ec441f6ff5.42447309_img040.jpg
This from stock pistol(after adjusting trigger) & I'm a shaky old **** that drinks to much on days off LOL- thought I would re-crown, but decided not to after seeing results. Not shabby for a El Cheapo. Bullseye same diameter as .177(white dot)I love to tinker but @ some point need to leave it be.
 
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If your gonna shoot open sights as come from factory, mine was shooting 3" low @ 10 meters & could not raise elevation any more, so longer screw or file down front sight(its plastic but go slow & re-check)
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The gun has a long flexible steel (or wathever material is) barrel. The first I notice is that if you hold the gun from the front, pushing even a little the barrel against the cilinder, the barrel just bends tounching it with the tip. Is very posible that a bad position or wathever cause little deformations over time, and also the entire barrel may vibrate at each shot.

The PP700 is reviewed as more accurate, but the simple reason may be its barrel binded whith the cilinder, or just the fatter barrel in early models.



Just a novice hipotesis... anyway, I think it may help binding the end of the cilinder with the tip of the PP800 with a custom piece.
 
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My 177 is regulated to 650fps, but has the regulator plenum deleted. 36cc air capacity. Was 22cc with the plenum. As I'm sure you know, the plenum provides more air volume of regulated charge. For more power. With the plenum my power topped out at 760fps down from 850 unregulated. But I get 52 shots dead on 650fps and quite a few more steadily tapering down 

Now if all you want is power, then bore the ports to 4.5mm, and get some shims/weights or a heavier spring for the hammer. But your power curve will be abysmal. As will the shot count.



Now, I do have a 25 caliber that has been power tuned. But I backed the tune off to flatten the curve out, and increase shot count/quiet the gun down. Peaks at 28fpe 680-620fps for 8 shots. Was making 30fpe prior, but was wasting a lot of air, and velocity dropped a lot faster
Click to expand...

Hey Dallas,

If you don't mind my asking on this thread, how did you get the .25 so strong?

Mine came thru Canada, and so far just playing with spring I have not got a obvious increase over the 400 to low 500 fps. I would be happy with 10 lethal accurate shots. So far it is a different animal all together from the .177 and .22

I would appreciate any hands on wisdom you can share
 
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Well, I finally got back the gun, now I'm waiting for a mini-drill tool.

I can give any size and shape to the holes, some people recommand to give concretes inclinations to the ports to redirect de air flow or something... does that really matters? I mean.. its the increment of pressure that pushes the pellet.

Is something like that the ideal?:

 \ \ (Barrel)

| | (Transfer port)

/ / (Valve transfer) Some say that the hole in the valve transfer must be a little bigger than the other 2.



I also think about reducing the diameter of the push rod that introduces the pellet, as it may take volume or dificulting the air expansion, can that help?

c=< ================DDDDDDDDDDDD

(Pellet) (Part that pushes the pellet) (Push rod that seals the air)
 
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Long_Gun_Dallas- I added Huma reg(with plenum) but can't figure out best pressure to set it at- Currently maxed out @ 150 bar(seems high for .177) getting 630's(very consistant) but have hit a wall trying to get 700fps- getting at least 27 shots- maybe shim HS a bit? Hesitate to mess with TP. Any thoughts? And McMaster Carr springs that would fit(size wise)
 
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Sent mine to my friend Mike to have him work his magic on it- he's looking @ re-doing the valve with better poppit setup & also working over my Huma so it functions better, along with a longer better barrel- stated that Tp is correct diameter for .22 but that .177 & .22 are the same, so my .177 is oversized(so recommend NOT enlarging on .177) Also plans to make HS adjuster & stroke adjuster incorperating rear stock screw.Did same for my .22 Gauntlet. Anyway, will keep you posted on results.
 
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1585655035_11061007005e832cfb9fce21.54627174.jpg




Due to the recent pandemic, I got a lot of time to work on the gun...



First, to hell with the ugly grips and balance point, I 3D design a new grips and a ''shotgunish'' pellet recharge system, it was hard to get the exact measurements, and also need to cut one screw or another and put a 2nd trigger (enourmous) in a more advanced position.

Second, I want POWER, don't mind if I get 10 or less shots per fill, I want that .177 to go supersonic and penetrate anything, cause I want a small game hunting gun apocalypse ready.

I open all the ports to 4mm with a mini dremmel, upper one in more larger shape to not affect the pellet, also grind the valve rod at the part that pops to allow more air flow trough the valve, and grind the back end of the valve rear that is striked with the hammer to open it more time. Don't have any idea of what fpe to expect... didnt have a chrony either...



Working on the ''Griffon'' freakish remodel of the PP800, I will upload pictures when it's done, and results when I can test it out.
 
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Hi my names Pete .. I’m from the Uk but now live in Spain . I bought a PP800 in the UK which has fairly draconian legal power levels for air pistols - max 6flb. Here in Spain this is not an issue and I’ve been trying to improve its power. I need 10 good shots . The gun started around 5lbs with a heavy .22 pellet. I have polished the hammer ( along with the obligatory trigger mech polishing ) placed a quarter inch shim inside the hammer housing to increase the spring compression on cocking ) drilled the barrel port to align it with the transfer port and the transfer port itself ( at 4.5mm - they were 3.5mm and not aligned properly ). I’m now around the 7lb mark for my 10 shots but would like to improve some more . I wonder if someone can advise me please . I think my options are to increase the diameter of the hole that feeds the transfer port . Increase spring power a bit more or make some modifications to the valve but I don’t what to do there. I have minor facilities - pillar drill etc but no lathe so I can’t turn anything . All suggestions very very gratefully received as I’m running out of things to do ... lockdown here in Spain has been very severe and loooonngg !! Cheers Pete
 
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