pp800r tuning

[2A Georgia]

How many shots are you getting at 26fpe?

It's not regulated, so 2.  I get 5 in the 23-26 range and about 10 that will shoot in a kill zone without any hold over/under to 30 yards.  But I do know the gun well, so I can glance at the gauge and immediately know where to aim.  Or at least very close.  I'm just really surprised that the jsbs are hardly affected by the massive shifts in power/velocity.  This is obviously a close range gun as it's a pistol.  Mostly just shoot it for fun.  It's got a pretty decent kick for an airgun.  Sounds pretty cool, too.

Hello Dallas  and others,
I have purchased a pp800r 22 caliber and added the BR pistol grips.  I am looking at TR Robb's website for the longer valve stem and enlarged  TP.  Any opinions on the standard (3.5mm), enlarged (4.0mm) or Jumbo (4.2mm).  I enlarged a 2240 stubby including at the barrel so I'm prepared to port the barrel to 4.0 or 4.2mm as well.  With the regulator my ES should be flatter and my fpe lower than your tune.  My goals are 20fpe if possible over 1 mag.  Any thoughts would be appreciated. My use will be similar as a holstered tool to accompany Crossbow or MSR during those seasons which here in Georgia are concurrent with small game. 

[2A Georgia]

By adjusting the regulator I was able to get a 7 shot 9fpe tune using JSB15.9s at 185bar fill with a 2% ES

[2A Georgia]

Reposting here
Before and middle pictures.  Tore down the SPA 800r to this point without looking at the Utube video.  The gun is incredibly simple and logical to work on.  At first I was a little salty that I needed to keep switching H2,H3,H2.5 but realized that's part of the idiot proofing for re-assembly.  Almost German of those Chinese....
Still to do;
Drill out barrel at TP to 4.0mm (to match new TP)
Trigger assemply polish job.
Watch the video and remove the valve for TR Robb stem swap
Re-assemble and chrono

The Hammer, Spring and guide are so well matched I don't see any mods a spring swap might not fit other than longer...may have to figure out shims if needed for tuning.

Down the rabbit hole I go

[avator]

You might find some tips in this thread.

https://www.gatewaytoairguns.org/GTA/index.php?topic=182687.msg156081653#msg156081653

[2A Georgia]

You might find some tips in this thread.

https://www.gatewaytoairguns.org/GTA/index.php?topic=182687.msg156081653#msg156081653

Thank you sir!
Sadly I am reading that thread after receiving my 4.0mm TR Robb TP and drilling my barrel to 3.91dia.

So today
thanks to another post about the leather belt and vise grips I got the end cap off the air tube.
The tube was not as greasy/filthy as past reviews and posts had indicated but I passed two wipes through it and its all shinny inside now.
I micrometered the valve stem at 2.71mm OEM and 4.32mm with the TR Robb aftermarket so 1.59mm to play with power increase and possible BStally mod.
At least I ordered the 4.0mm TP instead of the 4.2mm, but in the interest of max power I turned the regulator another 1/8th turn CCW so reg pressure should be increased.
Since I had the 4.0mm TP I drilled the barrel out to 3.91mm and debured.  I then ran 5 wet patches all jet Black through the filthy barrel and went for the Makers Mark for the remaining tedious barrel cleaning.. a total of 12 wet patches and 3 dry to get to an acceptable light grey and pleased no feeling of burs or tearing on the last three dry patches!
Reattached the barrel assembly to the air-tube assembly and read your thread.
I stopped with everything ready for the polish job on trigger assembly and thought better of it for tonight since Memsahib is already asleep....something about the dremel waking her up "with that look..."
Plan to chrono this weekend weather permitting.

[2A Georgia]

Completed the trigger job/polishing and am very pleased with a crisp light trigger almost no first phase like I like it and a very crisp wall maybe 2.5 to 3 pounds or less (don't have a trigger gauge).  The pistola is filled to 150bar to confirm no leaks and will go to LGR tomorrow.  Will have to chrono over the weekend with SSS testing for another AG.

[avator]

IMO those SPA triggers are way under rated. They can be made awesome with very little polishing and adjusting.

[2A Georgia]

IMO those SPA triggers are way under rated. They can be made awesome with very little polishing and adjusting.

I have to say with today's session I am very pleased with the trigger after a little polishing and the TR Robb lube applied at key contact points.
I can't wait to shoot over the chrono and pickout a dot sight

[2A Georgia]

I was able to chrono now that the TR Robb mods are in.
4.0mm TP
1.5mm Valve stem extension
And I went to far by making a third change 1/8 yurn CCW on regulator was supposed to increase pressure but behaving like past the useful range of adjustment and shooting unregulated.
The third string showed a constant climb....
The gun was 500fps 9fpe and is now peak 465fps and about 7.5fpe but with 16-18 shots versus 7?
Went to get some shims thinking I need to overcome the initial valve pressure.  With the HS Guide inside the detent in the end cap  three, two and one shim did not cock.  After much experimenting I just reversed the end cap for about 1/8" effective shim.  We'll see what next chrono shows.  I also degassed the AG and will try to go 1/4 turn CW to see if that gets the regulator back in the usable range.

[2A Georgia]

Degassed and turned regulator back in 1/4 turn, appears to now be regulated and slightly increased fps.  Not sure is I should inch bach the regulator 1/8 turn or do 1 oring Bstally.  Or slap in the OEM TP???
So with the 4mm enlarged TP and barrel, and extended exhaust valve stem I was expecting an increased (above 500fps/9fpe) output, not decreased.
This string is better, but feel like I need more hammer spring or less regulator pressure to get back to a 10fps ES.
Interestingly with the mods I'm increased from 7 to 14 shot count???

[2A Georgia]

So the TR Robb Valve Stem is 1.59mm longer.  The PP800r came with spare orings two are possibles for BStally one fits snug but is 1.79mm thick so probably the same valve travel with a little compression or one that is loose on the stem but 1.45mm thick so .14mm more valve travel.  Pondering on which to try first and possibly turning back the regulator another 1/8th turn.

[2A Georgia]

Sunny day Memsahib says I spent three hours with the chrony....
First run with the Bstally gave bell shaped curve peak at 484fps (still under pre-mods...)
Second run not really better but both runs 14 shots
Third run had an ES of 33 and peaked at 479fps Last seven shots ES 16....
Tear down and install the factory TP ES 33 and peak 496fps on shot 8 right at pre mods speed....
Found my Glock 21 Slide tuning spring set and them summa guns are the same OD as the PP800 spring.  Cutting three coils at a time on the 4th iteration I got the gun to cock.  True SSS as it was sliding around in the breech after firing ....abysmal ES 117 and peak 410fps, but 7 shots only used 20bar or less
The final run (factory spring) I waited 10s between shots and ended with an ES of 28 and a peak of 494fps over 7 shots.  Guessing my regulator is around 125bar.
I think I need to figure out some shims...considering the factory TP without the Bstally.....
With the Bstally the report is a very crisp pop versus a gurgle-burp....

[2A Georgia]

Tested 4 shims 3.2mm gave a tighter ES and the same fps.  Went to 7 shims  5.6mm (inside the hammer) spread around 10fps and 490fps peak.  I'm thinking I will 45 degree port the valve exhaust port next.  Learning to make one change at a time.

[2A Georgia]

I rememberred reading someone had made a venturi shaped TP for another member for the pp800r.  Looking at my valve considering porting, I noticed a reverse venturi effect in the OEM valve.  I opened the constriction up to 3.1mm to match the existing 3.26mm bore. I then used my countersink drill bit to bevel the OEM valve to 3.2mm to match the valve bore and start the venturi effect. 
In a true SSS prospect moment I forgot/lost my B Staley oring somewhere on the man-cave bench so technically changed 3 things again.
We now have a 14fpe pistola.  I waited 10 seconds between shots on the second string as we have a little reg creep.  The string will be 7 shots from 190bar to 140bar, but I shot the last JSBs which took me to 100bar and off reg.  as near as I can tell the reg is about 125 bar.
Next plans
reinstall the Bstaley AND 1/8th turn CW on the regulator to try and get to 135bar right at the 8th shot (want a one mag shot count).
see if this badboy can group the NOE Hunters
You will need to avert your eyes as I did my best Irish jig when I say the 14+fpe peak :-)

[2A Georgia]

Field stripped the SPA800r once again to turn the regulator 1/4 turn CCW (higher).  Counted 7 shims so 5.6mm hammer spring pre-load now.  Chrono soon.  I looked at the valve a long time with the dremel in my hand considering cutting 2-3 threads of the end...settled with sticking the ball shaped grinder in the opening to add deminimus more volume...lol

[2A Georgia]

Turned the regulator out and then back in.  I think I'm in the useable range of the reg and still under springed.
I might experiment with 6-7mm of a solid dowel for preload instead of the 7 washers (thus adding more weight to the hammer as well).
Looks like a15fpe pistola with 6 useable shots at 4% ES.  Not too shabby :-)
The final chrono posted is with Apollo 18s, but the mission will be to group the NOE Hunters, which would be my .22 pellet

[2A Georgia]

Got a 3/16" threaded rod from Lowe's and cut a 7mm shim (still inside the hammer so added weight).  Two strings first with Haddes 15.89 about 43fps ES and second with the NOE 217RF dropping at 19.3 about 30fps ES and 15fpe.  I shot a couple Apollo 18s and they fed better than the NOE cast.  Group test will be Cast 19.3, JSB 18s and Apollo 18s to see what it likes.
I have been praying over optics; BSA Edge 2x20, Hammers 2x20, Romeo 5 1x20 2moa, Hawke 1x20 and Vortex 1X20, and the Holosun green dor and circle dot...
So many choices...
One side says no batteries and no star with the 2x20 and the other says unlimited eye relief and easy holster with the 1x20 micro red(green) dot....hmmmm