Artemis/SPA PP800 in .25

[bluemoon_wulf]

A few weeks ago I ordered from Wes at airgunarcheryfun.ca this pistol. It is tuned for Canada, so I will see what can be done eventually, after I finally finish my wife's crosman.

I like how it looks.

Easy to pump by hand.

Definitely louder than the amped 2240.

Grip is for large hands.

The bolt is smooth and trigger feels fine. But don't forget I am new, only a few triggers in my time.

Loading jsb exact king heavy diabolo ii in 33g, the bolt is not happy. Have to force it closed. Benjamin's are fine. So some porting is a must for heavier pellets.

Have not cleaned the barrel or oiled or polished yet, just played. With red Dot, at 20 ft (my inside living/dining range) I think it does pretty good.

My cheap paintball Chrono does show a wide range tho.

I have no idea how accurate the box is. The fps is the only number to count on. The Jules is based on drop down selection weight. Not the weight of the Benjamin's.

Even tho Wes had mentioned this gun on the forum, not sure if he made clear how rare it is.

The .177 and .22 are magazines and are every where including Diana. The .25 is not Diana, is single shot and not easily found on Google.

Hope this has been interesting enough. Thanks.

 

[marflow]

if the trigger assemble is like the Chase there is lots that can done

and this part I was wonder if it fit a Chaser

http://www.canadashootingsupply.ca/caliber-conversion-kit-for-pp800-or-diana-bandit-to-0-25-cal.html

enjoy your new pistol and happy holidays

mike

 

[Long_Gun_Dallas]

I have one as well I ordered from him. Only ever heard of one other person owning one.



Mine has 5.1mm ports throughout. I think I maybe should have gone a bit smaller. Added 2.5mm valve stroke. (valve body appeared to be longer, effectively limiting hammers ability to open the valve) gun was definitely detuned for Canada. Can get 8 shots in the same hole @ 30 yards. The gun prefers jsb 25gr by a large margin. 22-26fpe



I'll be interested to see what you do with yours

 

[bluemoon_wulf]

Hey long gun

You know way more than me.

I get the port sizes. No idea how you would alter the valve stroke. Cut the valve body?

I am glad to hear over 20 fpe. That is my goal also. Don't want any fuzzys to suffer.

Not sure how soon I can start disassembling it, but I will post the results.





Marflow..... I don't know. The body can be exchanged for other models. Not sure about the breech

 

[Long_Gun_Dallas]

Hey long gun

You know way more than me.

I get the port sizes. No idea how you would alter the valve stroke. Cut the valve body?

I am glad to hear over 20 fpe. That is my goal also. Don't want any fuzzys to suffer.

Not sure how soon I can start disassembling it, but I will post the results.





Marflow..... I don't know. The body can be exchanged for other models. Not sure about the breech

I actually chucked the valve stem with the seal on it, spun and cut the seal back a little, so it would seat deeper. Creating a hair more valve stem protrusion. I also reduced the length of the valve body on the hammer side. Have to be careful because this end sits in a notch under pressure. Mess thing up there, and the body won't seat in the tube in alignment with the transfer port. I have a bandit I've tuned, but have not really modified. Both in pieces, side by side, the severely limited valve travel on the pp800 was very apparent. 

Hatsan seems to have their ports on point. I have a sortie in 22 caliber, and the consistency across a 100bar pressure drop is shocking. I have no idea what port size they use on their 25 caliber pistols, however, but I would use the same size if I knew. Of course vlave and hammer tuning affect consistency as well. So, even with the "right" port size, there are other factors.

 

[bluemoon_wulf]

Long gun

If I understand right, if I get a valve made for the bandit, it will work better power wise than the existing Canada valve? Even tho only .22 ?

My shop is my kitchen table so no milling for me.

I appreciate you sharing your hands on. By the way, any suggestions on how best to whittle the wood slimmer?

Thanks again

 

[Long_Gun_Dallas]

I had wondered if the bandit valve body would be a better choice. It seems the alignment would be the same. But I can't confirm 100%. I am 95% certain it would work. FYI the 25 and my .177 bandit have the same size ports. 3.5mm IIRC

The valve is the original. But the valve seal has been cut back. And the back side of the valve body where the hammer hits is shorter now, so the valve stem is exposed a bit more. If you take the valve apart, you might see what I mean. the hammer hits the stem to crack the valve. The seal is on the other end of the stem. If the seal is cut back, it changes, the point on the stem at which the valve seats. So, that would extend the amount of valve stem poking out of the back of the valve body (where the hammer strikes) Increasing valve travel when hit by the hammer.

As for the valve seal, I just put it in a drill (you aren't supposed to do this, haha, but if it works.....) Used a file and finished it off with a few different sand papers, then polishing compound. Gota be careful, though. If you use a drill chuck, you can get some pretty bad runout very easily. I just eyeballed it, and measured/rotated it in the chuck periodically. That was to move the seating point of the seal further back on the valve stem.

The only real differences in the guns is the hammer spring, I think. Though it may share the .22 one. I do know it's not the same as my .177.

As for the grip, patience, and a paddle wheel will make short work of the initial rough griding. Just have to be sure not to over-do it. The rest I did with stone and sanding dremel bits/hand sanding as well.

My bandit had a newer style grip. But was seemingly equally as bad as far as dimensions go. The angle towards the air tube is the opposite of yours.

I ordered the pp800 with they synthetic detachable stock.

 

[Vetmx]

What I have found with SPA pistols is they all use the same valve. The stem doesn’t stick as far out of the valve like a Crosman valve. The porting on my .177, .22, CO2 pistols, .177 PP800 and Bandit were all the same. I believe they control the power with the hammer spring. With this approach, the tune on all the pistols is jacked up. How can you expect a CO2 pistol operating at 800psi and a PCP operating at 3,000psi to function properly using all the same components. I shim the valve spring in the valve to get it to close faster because of the short barrels and use a patch from an inner tube on the face of the valve like a B Staley type mod to get things operating efficiently. Then I focus on the hammer spring and eliminate hammer bounce. These pistols are the equivalent of something designed by an 11th grade Vo-Tech class but are fun to try to take an archaic design and get the most out of it. If I had a .25 I would port it to 4.9mm open up the interior of the valve for more volume then focus on controlling the dwell. Then dial in the hammer spring and control bounce. I also believe the hammer in all these guns is too heavy. It is so heavy that you can feel it every time you pull the trigger. 

 

[Long_Gun_Dallas]

That's all good info. I did reduce the hammer weight and hammer spring tension drastically on my .177. I havn't done much tuning on unregulated guns (pistols are more challenging, in my opinion). So, I'm still learning, and trying to pick up more info.

Have you managed good spread with one of these guns unregulated?

Also would be curious for more info on the valve face mod. Can't say I've heard of anything of the sort before. 

 

[Vetmx]

As I moved the Bandit in the direction of having a nicer usable spread, it was headed right towards regulated velocities. That’s when I gave it to a friend for a garage gun. I still had some ideas but had other more intriguing projects waiting. I shoot PCP’s for one reason, consistency. Having a usable curve with that tiny tube is tough until you slow the gun way down. Problem is when the manufacturer advertises that speed, nobody would buy the gun. So they just smash the valve real hard at 3,000psi, get a max velocity and post that as the speed of the gun. With the .25, you need to focus on a giant blast of air with a very quick dwell. As far as the rubber on the face of the valve goes, it’s just a shortcut to limiting the valve strike and softens the blow and helps it be consistent. It’s no different than guys jamming orings in their Benjamin guns. It’s shade tree, but it works if you don’t want to spend weeks dropping grams off your hammer and playing with springs. Hitting big power numbers with an unregulated gun is easy. Doing it and having a useable ethical shot count for hunting is more difficult. My favorite topics are guys working on these guns. Like I said over on GTA, the guy who comes up with the right combination on a Bandit style pistol will be a hero. Most, just like me, loose interest because when you finally get the pistol moving in the right direction, it gets too slow for our power hungry appetite.