PP750 Artemis Tear Down and Tune Up

[PiotrBBurzy]

So There we go ...
I'm so happy because its my first tune ever.
I am getting 150 shots from that pistol. LOL

JSB 18.13g 402FPS on average with 8FPS  spread
JSB 15.89g 414FPS on average with 12FPS spread
JSB 14.35g 445FPS on average with 14FPS spread

I forgot to mention yes its in .22 I am wondering what you can squeeze from .177
IF any one attempted max shot count in .22 or .177 please post.
Grouping on 20 meters with red dot amazing.
I had 80 consecutive shots in 10p coin. 

Idea is brewing to make cnc alu bridge port for bigger 0.3L bottle. with digital gauge etc.

[PiotrBBurzy]

First shots out of the .22 PP750 with Canada 1.80mm port, no regulator adjustments factory set point @ 122 bar.


Filling to 200Bar shooting to 122Bar nets about 27 shots using 2 turns in on the hammer spring.
So far barrel likes: JSB heavy, JSB  Hades, HN FTT 14.6,  3/8" 10 shot groups at 25 yds.

Right now the comfortable tune is 2 turns in with the HN FTT at 640FPS making 25 shots from 200Bar to 122Bar.

I went through some pallet samples. I did some job on crown and that is result. This RS JSB are amazing I got near zero flyers.
I'm set to 500FPS div have cleaned regulator and changed seal on reg head. Divination i get is between 2 and 4 FPS depending on string .
I do discard firs 3 shots after refill cos they always of chart. It gives me 80+ shoots.

[Hawkeye51]

Piotr
Great results shown in the above post. For using a red dot, it's hard to be more accurate than that. Quite interesting these little pistol/carbines can have such a wide range of tuning. Most guys are tuning up for power, but you have tuned down for shot count and still have enough power for pest control. Well done!

[Back_Roads]

 Well it has been a bit over a year since I got mine in .22, shot it factory stock for most of the warranty period, while gathering a 16" barrel and assorted LDCs etc..
 The other day I had air escape while plinking in the cold, with the 16" barrel it was shooting around 585 fps, with Canadian parts 16 gr AA pellets and the longer barrel, gained 85 fps.
 Took it apart opened up the barrel and TP to the same as Thane did, but left the grooved thimble 2 ports as is, set the reg at about 150 bar, 2 threads showing on reg adjustment screw. now getting 18+ shots at 830 fps, 24.4 FPE with 16 gr AA pellets, need to test more ammo as this is a fresh barrel and new tune, so there is that fun task to do yet.
 All in all it is one of the easiest PCP air rifles I have taken apart. No screw heads that easily strip like say a Prod.

 PS From my findings the air leak was from a loose screw on the block that leads to the poppet/ valve area, that allowed air past the oring seal.

[Hawkeye51]

James
Tell us where you sourced the barrel and did you thread it to fit or bought it threaded. Have you streached it's legs yet? Like 50 yards or so.

[Back_Roads]

 Ready to screw on from here https://airgunarcheryfun.ca/pp750-long-barrel-16/
Have not gotten past 10m with it after mods, cold weather old n all

[PiotrBBurzy]

Thane I have to say there is lots to blame you for.
1 I have mini Chinese monster in my front room
2 I have ordered all needed tools for it which was more than lathe itself
3 I never used it before so i have lots to educate myself! nights are short now very short

I had manage to fit 630mm .22 blank on that ?pistol? it was fun till 3 hours later.
I did cut barrel so choked part to be 11 inch siting in shroud. Second part of blank will is unchoked and will be subject to experiment with slugs.

I will post soon ....
broke my insert and still waiting for new 4jaw independed chuck   
 

[rash_powder]

Looking at Piotr’s pistol I can’t help but wonder

Is there a longer air tube we can use??  With the longer barrel it just seems like we should be able to put a bigger reservoir on. 

[PiotrBBurzy]

Yes you can get one from other air gun makes or go china .com
tube of 500mm length up there is about $39
I am looking forward to make Z-valve rearrangement and hung on with 500cc carbon bottle 

[Thane]

@PiotrBBurzy looks really good!

Enabling is one of my skills...

I am amazed how small the plenum is and how much barrel it will support.

The Umarex variant will bring even more modifications, fun times.

[PiotrBBurzy]

Wondering if this my rev.6 plenum block can double the shot counts ? sourcing tomorrow and hoping to get back with some numbers soon.

I just got devastating news from WES ... it looks like my plenum is missing in transit.
Bit off shame I was going to set it with other barrel I have prepared  for slugs.
FFS I was hunting for it since summer.
I will put together some new finds about this "pistol".(groups with chocked weihrauch barrel and some works with carbon silenced shroud)
I had experimented and have shoot some unregulated with leaded hammer and custom springs. Have to say I had pushed it to 36 FPE.
Yes it kicks

[PiotrBBurzy]

Some show-off I can turn some of things in my to small lathe 

[Hawkeye51]

Piotr

I like it !!!

[PiotrBBurzy]

So I have some news.
First there where issues with my first version off carbon shroud. It was very nice and quiet but I have noticed it was LDF was clipping my pallets:( Holly grail of lathe works ... concentricity is must and always checked. But my skills improving quickly. I run two barrels made of one length 630mm Weihrauch blank. So i have choked and unchoked setup.
I had reworked all idea setup and I have end up with barrel tensioner. At the time i had no clue it will work that way. Recently i was watching FX development of barrel tensioner for 800mm long barrels.
I started to play with it and it works you can tighten your groups:)
Now no bottle yet but I will come eventually. Gun reg is set 100 bar its Huma but now I agree its not must as original reg is very good quality.
I have hammer drilled and led washers pushed in. Hammer spring is changed to. Spring behind poppet valve changed to lighter one too. You don't need that original monstrous. Valve will close under pressure any way. from full fill it gives me 70 shots in 12FT Lbs. Just to stay with UK boundaries.
Thanks to Wes (amazing service and prompt answer to all questions highly recommended) I have bigger plenum and gauge on reg.

[PiotrBBurzy]

And some photos of my tinkering attempt.

[PiotrBBurzy]

Slugs at 30 meters.
18 shots on average with 18.5FT/Lbs
JSB KO very nice grouping. I was taken a bit by surprise how it kick a gun.

I have also checked if pallets will hold and well well well. They do! 

[Thane]

Nice 30yd slug groups!

Great pesting gun.

[Thane]

Some changes to the PP750 in .177 for Pistol Field Target:
Bottle drop block with adjustable Ninja Regulator and carbon bottle.
Carm single shot loader.
16mm Lothar Walther slow poly barrel 14.9 inch length removed thimble and threaded blank to insert directly to breach block, added transfer port.
1/2-20 slip on adapter for practice moderator, too long for competition rules.
Dovetail slip on over barrel to move scope forward.

Makes 12FPE limit easily @ 1250 PSI, 3/8" ten shot groups at 35 yds.

Learning consistent holds is something I am still working out.

[bear air]

That pp750 looks awesome. Where did you get the drop block?

[Thane]

That pp750 looks awesome. Where did you get the drop block?

You will need to run a tap to finish out threads, and shims or surface down face of block to clock it when it seats.