El-cheapo Artemis PR-900 - the mule

[Racing]

At the shop of mine the most dangerous of times is the coffee breaks.
That´s when all the moronic notions and ideas are shot across the room. So. We started talking right and as the gang has a past within pro motorsports amongst other trades, yeah well.. we love hotrods.

Question came up, me being a part time gun smith, how far can you push the cheapest of PCP guns when it comes to performance? Ie; both power and accuracy.
Later the same day i saw an ad for this...



..which was a used Artemis 22cal PR-900 of Series 1. In short an about as basic PCP rifle there is. Forked over 120€ for it, it lacking its magazine. Still though, that´s not exactly a lot of money for a PCP and the thing was in great order.
Back at the shop i popped like 10 round off, enough. At a mere 10J.. enough already.



Well known i´d say!



We use our PCP´s for pest control. Namely rats, and doing so we need to keep it quiet. The PR 900 lacks provision for putting anything out front basically so i turned a press fit adapter in a hurry, one sporting the industry standard 1/2"UNF thread.

While at it i have to say (and as we were to discover) that barrel wasn´t half bad as far as the rifling and choke goes, however.. the muzzle crown coupled with the chamber and in turn the forcing cone HAS to be one of the worst jobs i´ve ever seen. Cheap rifle in its own right but hello!

So. While the barrel was on the lathe we did a "first pull" as far as those bits, and as it turns out.. well..



Yep. We turn our own cans. Hadn´t gotten around to make one specifically for the PR at that rate so simply stole the one off a Hatsan BT-65. Works for now, what can i say?
Indeed it does make wonders for the sound level. No argument there.



These guns do NOT sport anything close to a "match trigger", then again.. not to be expected on a 120€ gun. Parts out of what we´ve come to call "chineseium". Point being that they´re out of steel alright, just hardened to a point where it becomes stupid brittle.
How i know?
Well. For some reason Artemis decided it was a good idea to put the only adjustment there is, for creep, on the trigger blade. I however beg to differ so i took the centermark for a drill right.. and the sear just snapped off.



Yep. Now, lucky me as i not only own an AC/DC TIG welder but know how to use it as well so albeit the parts might be small the thing was back in one piece in no time and WITH an added M3 screw hole for a grub screw so creep could now be set at the sear instead - where it´s supposed to be.



Ah. Within the tank resides the valve of course, but a "depinger" as well that doubles as a tap off for the pressure gauge that sits underneat the stock. Never having worked on Artemis guns before i took to altering what was there.

I bet someone will come to explain to me why, but for some reason Artemis seems to be hellbent on putting the softer piece of the actual valve n seat on the poppet.
This, as power goes up substantially, turns out to have drawbacks. I must have reworked that poppet like 10 times before i went "to hell with it, i´ll redo the entire thing".



It about came to drive me up the proverbial wall, cause where we were at that in later guise press fit bearing bronze seat.. it would move no matter the amount of press fit and even hard core industrial epoxy.



In action pictures rarely tell of the finished product. But here.. that adapter, and at that the now reworked muzzle crown.



For the actual valve pin these guns rely on a mechanical fit to seal the pin off vs the housing. Well, enough of that already so an endmill later we had countersunk the housing to take a 3mm o-ring. As the pin is 2,90mm though i fabbed a "lid" with a small divot that runs up against the o-ring and compress it. Presto, snug fit AND a way tighter seal - for air heading for the pill to be shot downrange.



At that point i had enough of the stock solution so i turned a poppet out of solid hardened steel. Then a 12mm endmill to the valve housing, boring it out, to which i installed a POM (tough plastic) seat with the downright MASSIVE press fit of 12,30mm. Ie; 3/10mm.. Even turned a tool to be able to install the thing on the hydraulic press.
Done deal and presto.
NOW we were getting somewhere!

At this time i drilled all passages out to 5mm flat and then in turn the valve seat through hole to 6,5mm. Poppet outer dia was set to 7,5mm, so as you can gather.. not all that much width to seal the thing. But it does, with flying colors.