I do have to say, modifying the PPK to Full Auto is not recommended, mine originally worked well but the heavy blowback in full auto eventually broke the firing pin setup and I lost it somewhere in my back field. I had to Macgyver a bolt in place to kind of work but now my Full Auto Modded PPK shoots out of control, what I mean by this is when I press the trigger, it does not stop shooting until all the BB's are gone. Safe, I don't think so!
My suggestion is to leave the Umarex Walther PPK as is, it truly is a an awesome CO2 Blowback BB replica with some really decent blowback recoil in a small airgun.
After many many requests to show how the Umarex Walther PPK CO2 Tab Modification is done I have relented to public demand. I don't actually cut my tab in this PPK CO2 Tab Modification Video but I do go step-by-step in detail and compare my modified Umarex PPK to my unmodified Umarex PPK. It is really very basic on how this is done and only a hack say and perhaps a file are all that is required to make the modifications to the PPK CO2 tab in order to make it flush with the bottom of the handle area.
Your best bet is to simply watch my YouTube Video located below and follow the steps there but here it is in text form:
Place an empty (already pierced) CO2 into your Umarex Walther PPK and tighten the unmodified CO2 tab until fully tightened, just like you would tighten a fresh CO2.
Take note at how many threads are exposed between the bottom of the handle and the top of the plastic CO2 tab, there should be about 2-4 threads exposed.
Unscrew the CO2 tab all the way, place the PPK BB Pistol so it is secure (in a vice of some sort) and use a hacksaw or dremel to shorten the CO2 screw just above the plastic tab at the thread location you previously noted. Be conservative as you can always cut or file the screw a bit shorter if your first cut was not short enough.
Now use the same hacksaw or dremel to cut a notch in the exposed cut area of the CO2 screw so that you can use a slot screwdriver to tighten the CO2 screw.
That's it - Enjoy your modified Umarex Walther PPK CO2 BB Pistol!
Watch my Vimeo Video of the Umarex Walther PPK CO2 Tab Modification Tutorial:
Another filed test video in the series. This one is of the Umarex Walther PPK/S CO2 4.5mm BB pistol, I show you both my regular unmodified all black PPK/S and shoot it through my Chrony Chronograph with an averaged reading of 282 FPS, not bad considering the manufacturers claim is 295.
I also shoot 8 rounds with my stock Umarex PPK/S at a target to see what kind of accuracy I get, and just for fun I shoot a 15 round magazine into the same target with my modified fully-auto sliver slided PPK/S.
To finish things up, I slowdown the action just a bit using my high speed Casio camera to capture the blowback action of both my stock and modified Umarex Walther PPK's.
Enjoy my YouTube Video of my Umarex Walther PPK/S CO2 BB pistols getting Chronographed, shooting at a target and slowed down a bit with my High Speed Camera.
This is a video I posted on YouTube a while back that has gotten a lot of views (Now Over 300,000). It's basically me and a friend shooting a couple of guns. The first set of guns (One in each hand - Tomb Raider Style) are two Walther CP99 Compacts made by Umarex. The CP99 Compact is a great little BB gun with a very fast and light trigger pull.
Next up is another Umarex product, a Walther PPK. This one is moded to fire Full Auto, making it one of the smallest Full Auto BB Guns. Too bad it's all over so fast! I'll look at doing some proper reviews of these fine Airguns down the road...
