This is something I've been meaning to do for some time, but never got all the elements together for it.
The Pedal air gun has a good deal of power, and the thing to do is to fire it through a chroney at an appropriate backstop, weigh the projectiles, and publish the results. I had, after all been pushing this thing as a kids toy.
Most of the elements fell together this week. The scale, the Chroney, the weather, and an attempt at a backstop. Click the link and scroll down for a picture of the projectile, made from a 12 ga shotgun shell hull. For this experiment I fired 2 shots, one with a hull with the rear opening flared, and one with masking tape wrapped to make a close fit in the barrel.
Specs: Shell with flared end weighed 266 grains, and the one with the tape came in at 279 grains. A bit heavier than a .45 round.
Air gun pressure was 60 psi.
Measured velocities were 357 ft/sec for the flared projectile, and 366 for the one with the tape. This yields a power factor of 102, which coincidentally is the same as my CZ-82 9mm and right there with a .38spl service revolver.
The backstop is where things got problematical. Here's the setup:
Draped over a ladder were 2 pieces of carpet, with a woven hemp doormat about 3/4" thick in between. The thinking here was that the resiliency of the rig would absorb some of the energy. It probably did, but to be safe, I added a piece of 2 x 8 in behind. Shot #1 penetrated all 3 layers and bounced off the 2 x 8. The carpet hanging down the back would probably have stopped the projectile, but the 2x8 was good insurance. Shot #2 stuck in the 2 x 8. At this point, I quit.
Yes, through 3 layers of hanging carpet, and into the wood. The point on this is 1/4" dia and an inch long and the fuzz hanging out from under is the 3 layers of carpet.
So no more back porch ballistics. Any further tomfoolery will be done at the range.