In my last post, I was working to turn my Crosman 1322 into an air conserving pumper. In spite of achieving some success with a short spring, there was still a bit of a fart sound to the report, indicating that there was still hammer bounce. I decided to build a free flight hammer to eliminate hammer bounce for good.
The one disadvantage is seen in the above photo – you get a good bit of protrusion when the gun is cocked. I’ll be trimming it down a bit to make it sleeker. So how is it put together? I threaded both ends of a piece of 3/16″ drill rod to 10-32. On the hammer end, I threaded a nut on and ground its perimeter until it would slide freely inside the hammer. I took my already shortened hammer spring and slid it over the rod. The end cap was then drilled to 7/32″ so the rod could pass through. To reduce noise and vibration, a o-ring was added, and everything locked into place with another nut. Here’s what it looks like when removed from the 1322:
Cocking is still very smooth and easy with this in place. This is a good thing, in the interest of pursuing more power, I plan to install replace my shortened spring with a stiffer version.
What about performance? Well, it has dropped down to averaging 465 fps on an initial 10 pump charge, with 7 pump refills. It is very consistent, so I am definitely on the right track. I’m working on raising the power level in a couple of ways. I’ve already mentioned a stiffer hammer spring. To complement the hammer spring, I’m going to install a much lighter valve spring to reduce valve cracking effort.
As mentioned in my last post, I was wanting a more consistent powerplant. I opted to purchase a flat top piston and valve. The piston is adjustable and includes an oiler. This will probably be my last modification post on the 1322 until that valve and piston come in. Let me leave you with a short video clip that will let you see and hear the device in action: