Wanted to share the completion of my PP800 project.

[Long_Gun_Dallas]

Originally this whole idea came from owning and customizing a 17 caliber Bandit.  I found a 25 caliber PP800, essentially the same gun, for sale in Canada, and figured it'd make for a fun/cheap science experiment.  Reasoning that with how impressed I was with power output and overall performance of the Bandit, I could reproduce the same result, but in a much more powerful caliber.

It arrived originally shooting 12fpe with JSB 25.39gr pellets.  Sub 500fps per Canadian restrictions.  After modifying the airflow of the gun front to back, it shoots 26fpe, and holds very tight groups using the same 25.39 JSB pellets.  Which impresses me because there is no regulator.  Other pellets gave me more drift and drop/lift from center of aim on target.  For some reason the JSBs just want to go to the same place even with a 100FPS difference.

Of course many more tweaks and small things have been done overall to the gun, but here's the finished product.

[Tucobenedicto]

Very nice setup 

[Long_Gun_Dallas]

Thanks

[Rupertt]

I bought one of these PP800/Chaser fusions in .25 cal too. Light, tight groups at an affordable price point.
I am looking for a nice, lightweight solution for optics, and I see you have elected for a 30mm Red Dot and 3x Magnifier..?
As there is no Magazine for the .25 I'm guessing you slide the pellet into the single shot tray under the magnifier..?

I'd like to get my hands on an MTC Prismatic 10x30 Atom but can't find them anywhere yet.

"After modifying the airflow of the gun front to back, it shoots 26fpe, and holds very tight groups"

How much work did this involve; did you need to machine any parts, or purchase a regulator..?

Very cool project, well done Dallas..!

[Glem Chally]

Wow 26fpe from that pistol,  nice work there.

[Long_Gun_Dallas]

I bought one of these PP800/Chaser fusions in .25 cal too. Light, tight groups at an affordable price point.
I am looking for a nice, lightweight solution for optics, and I see you have elected for a 30mm Red Dot and 3x Magnifier..?
As there is no Magazine for the .25 I'm guessing you slide the pellet into the single shot tray under the magnifier..?

I'd like to get my hands on an MTC Prismatic 10x30 Atom but can't find them anywhere yet.

"After modifying the airflow of the gun front to back, it shoots 26fpe, and holds very tight groups"

How much work did this involve; did you need to machine any parts, or purchase a regulator..?

Very cool project, well done Dallas..!

The optics conaist of a discovery 20mm RDS that uses a aaa battery.  RDS  work very well for me on handguns.  And if I need to shoot further out, I can slap the stock and magnifier on.  The magnifier mounts well clear of the loading port, so it's not obstructed in the slightest. 

The scope you mentioned looks unlike anything I've seen.  Very cool.  I may have to pick one up as well 😂 adjustable parralax in such a tiny package?  😎

Power mods were a little extensive as the gun had an extended valve body, effectly shortening the amount of valve stem protruding on the hammer side.  I did a full port job first, and only gained 50fps.  (original ports were 3.5mm) This consist of a ported/bellmouthed  valve body inlet (5.1mm), hogged out valve body, ported valve seat (5.7mm to account for valve stem volume), and valve body outlet (5.1mm)  same for transfer port and barrel port.  The barrel port had to go thru the rear oring seat (right next to the TP seat) so I did have to cut a new oring seat rearward of it.  All ports matched and radiused.

50fps gain.  Wait hold up...  I took it apart and noticed how the valve stem barely protruded from the body.  So, I cut the body back a bit.  Aslo cut the valve poppet back a bit so it would seat a bit further back (allowing hammer to act on it further).  I streamlined the poppet a bit as well.  And I belive I shimmed/weighted the Hammer a bit, too in order to raise its power band to higher psi.  It peaks around 150bar  Uses about 5 bar per shot.   Afyer the second round of mods, I fired the first shot across the chrono.  672 fps with 25 gr 😮  didn't expect that.  It does 680 now.

Wow 26fpe from that pistol,  nice work there.

  Thanks 🙂  I was surprised.  It's wood griped twin is detuned by 10fpe down to 6 (regulated), so I figured I'd go all in on this one.

[Xraycer]

Wow 26fpe from that pistol,  nice work there.

+1

[Pelletjunkie]

How many shots are you getting at 26fpe?

[Long_Gun_Dallas]

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.

[Rupertt]

The optics conaist of a discovery 20mm RDS that uses a aaa battery.  RDS  work very well for me on handguns.  And if I need to shoot further out, I can slap the stock and magnifier on.  The magnifier mounts well clear of the loading port, so it's not obstructed in the slightest.

I have a few Discovery Scopes; I love them, but I had no idea they had a Red Dot line too.
The RDS and Magnifier came with Dovetail Mounts..? 

The scope you mentioned looks unlike anything I've seen.  Very cool.  I may have to pick one up as well 😂 adjustable parralax in such a tiny package?  😎

Etched Glass Reticle and 34mm tube should be a fast, lightweight, dovetail solution for this take down carbine..!

Power mods were a little extensive as the gun had an extended valve body, effectly shortening the amount of valve stem protruding on the hammer side.  I did a full port job first, and only gained 50fps.  (original ports were 3.5mm) This consist of a ported/bellmouthed  valve body inlet (5.1mm), hogged out valve body, ported valve seat (5.7mm to account for valve stem volume), and valve body outlet (5.1mm)  same for transfer port and barrel port.  The barrel port had to go thru the rear oring seat (right next to the TP seat) so I did have to cut a new oring seat rearward of it.  All ports matched and radiused.

Well above my pay grade, but pleased to know it can be done, and impressed that you got'r built..!

[Long_Gun_Dallas]

I have a few Discovery Scopes; I love them, but I had no idea they had a Red Dot line too.
The RDS and Magnifier came with Dovetail Mounts..? 

Etched Glass Reticle and 34mm tube should be a fast, lightweight, dovetail solution for this take down carbine..!


Well above my pay grade, but pleased to know it can be done, and impressed that you got'r built..!

Yeah, I'm tempted to try another small holographic discovery sight.  Theyre certainly easy on the budget!  They're both 20mm mounts.  I have a cut down UTG rail on the front.  And I have a springloaded 11 to 20mm adapter under the quick release on the rear.  That springloaded one is pretty cool cause it pushes outward and actually stays under the magnifier when I pull it off

That scope is pretty trick.  I'll have to check out their sight lineup. 

I used pretty basic tools to modify it.  Just a dremel mostly.  Cut the oring groove with a dremel and the barrel in a drill chuck so it'd spin it for me.  Steady hand, a sharp eye for detail, patience, and measuring go a long way.  I've cut seats by hand before, and in far less desirable circumstances.  The groove I think is mainly to align the barrel in the breech, but also helps seal it a bit.   Wish I had better tools, but I got plenty of time to get that together.  Still young and got a lot going on.

[Toddspeed]

Dallas, impressive work you’ve done with your PP800. I especially like that you aren’t intimidated to do challenging mods just because you don’t have the ideal equipment. I have also made good use of my rotary tool and hand drill, but you take it to another level.

Since you have such thorough knowledge of the Bandit / PP800, I have a couple questions for you. What do you think about the possibility of adding a bottle to increase shot count? I’ve seen some Prods where guys remove the front stock, and replace the pressure gauge with a threaded nipple, then mount a bottle. I know the Stormrider has a gauge threaded into a block similar to the Prod, what if you put the gauge block into the PP800 tube, drilled a hole in the tube, and put a nipple pointing down near the trigger guard? See the highly detailed engineering drawing below. What is your opinion about this idea?

Also, what is the distance from the trigger guard to the end of the tube?
The distance from the trigger guard to the fill port

[Long_Gun_Dallas]

Thanks   I think some of my best work has been done when I was right on the border of destroying something I wasn't sure I could replace 😂  not without buying a whole norther gun anyhow.   If you can envision it, you can make it happen.  Probably helps to have technical knowledge and lots of hands on experience, though 😂

If you had the gauge block.  Which the stormriders should fit perfectly....  I don't see any reason why it wouldn't work.  I'd be able to say more if I actually knew what the block looked like.  But I suppose the part I'm not sure about would be the fitting used to attach the bottle to the gauge block.  Of course you'd want to make sure the bottle was secured very well, and none of the fittings were exposed to external stress.  If all partdls are rated for 250 bar or better and are used as intended....  I'd go for it. 

I'll get some measurements for you in the am.  It's already too late here. 

[Toddspeed]

I know what you mean about destroying stuff, I recently completed a QB ‘mini valve’, I thought I was going to cut my valve stem short putting a channel in it for the E clip, but it worked. Felt like a huge victory cause I used a cordless drill and rotary tool.

Here’s a few pics of the Stormrider gauge block and some 1/8” stainless nipples, the only trick I see would be making sure the threads match, and like you said, securing the bottle to the pressure tube so no stress is on the fittings. But I don’t think that would be too hard. I really want to build a backpacker that gets plenty of shots per fill so I don’t have to carry my pump around. I think the Prod would be the best choice, but at half the price, I’m leaning towards the PP800 if this bottle thing seems doable.

[Toddspeed]

Here’s the other pics.

[Long_Gun_Dallas]

Ok, so the longest measurement you asked for is 8 and 2/3"  other is 7 and 7/10"  I'm pretty sure you'll need metric fittings for the block, but I have no way of knowing.

[Aeroman]

Hi There,

Not exactly sure where to post this, but i am having trouble removing my exhaust valve assembly form the "Tube".. Very tight, is there any special tool to "Hammer it out" or a wooden dowel... Just dont want to hammer it so much... Very tight in tube! Any help is appreciated as i am very new here...

Thanx