My start in airguns came in about 2005 with the purchase of a Crosman 781AK kit. I was unfamiliar with airguns and three of its features clinched the sale. The 781 is a single pump, multi-shot, BB and pellet gun. I don't remember why the dual ammo attracted me, but it did. I intended to use it for pest control and since I didn't shoot much, I wanted to be able to take a quick follow-up shot. I figured the multi-shot and single pump features fit this bill. This was also a spur of the moment purchase.
Fortunately, about that time, I came across the Pyramyd Air blog. After doing some reading, I began to realize the 781 was not powerful enough for pest control. So began my search for the perfect airgun. The RWS 850 AirMagnum had recently been introduced and seemed to be a good choice. If the Benjamin Discovery had been available at the time, I would have bought it (even though it wasn't a repeater)! This post also wouldn't be here (and probably not this blog). Anyway, I ordered the .22 caliber AirMagnum and couldn't wait to use it after sighting it in. Soon I had a chance.
The First Conversion
Crosman AirSource cut open
Finally I ran across an AirSource to Paintball adapter from Cooper-T. That was the ticket! It was a Crosman AirSource to ASA adapter with a check valve. After buying the adapter, I also bought a relatively inexpensive HPA tank and remote. I had everything I needed!
Remote quick disconnect; Cooper-T adapter (red)
Remote with Cooper-T adapter
A note about Cooper-T
Unfortunately the man who ran Cooper-T passed away. The Cooper-T web site is still up, apparently to clear out inventory. There are some complaints on the web about long waits getting Cooper-T parts now, but that may be understandable given the circumstances. Other sources for AirSource to ASA adapters have become available recently. My condolences to Cooper-T's family.
Now that I had my conversion, I was anxious to try it. I found instructions for a DIY chronograph and set up my own. For my setup, my first paper was 5 feet from the gun and the second paper was 10 feet from the first paper (15 feet from the gun). I set the microphone recording volume to 50% (but NO microphone +20dB boost) and started recording.
The conversion of the .22 caliber 850 AirMagnum performed as follows with Nitrogen. I used Nitrogen for this test because the paintball store I filled at only filled with Nitrogen. JSB Exact Jumbos were used for the test and velocities ranged from 591fps up to 602fps with an average of 594fps (12.38 average foot pounds). That makes this setup about the same as CO2 on an 80 - 90 degree day. (The CO2 results for comparison came from comments on the Pyramyd Air blog.) It was 73 degrees Fahrenheit the day I tested.
Was I disappointed with the results? Yes. I was hoping for better than CO2 performance, not just the same as CO2 at higher temperatures. The tank and remote setup is also kind of clumsy.
-Know what power level you need for hunting different size pests.
-Know where to aim to be humane when hunting. This may be different than where you would aim with a firearm.
-Quite a bit about paintball, high pressure air and air fittings.
I have gone through a couple more versions of the conversion that I will describe in future posts. When I am done with my latest version, I will also post that. Following are a few projects/discussions I am planning for the future.
-Discussion on air power feasibility: problems and some solutions
-Discussion on possible uses of air power
-More installments on the RWS 850 AirMagnum conversion
-Air powered R/C plane
-DIY chronograph (using phototransistors)