Showing posts with label ballistics. Show all posts
Showing posts with label ballistics. Show all posts

Wednesday, October 31, 2018

Basement Ballistics And Astronaut Training

So from the "Junior Mechanics Handbook" comes a couple more short projects. The first is a method of testing the muzzle velocity of BB and pellet guns. I called the second one, "astronaut training", mostly tongue in cheek, because a couple of older energetic kids could probably get this back yard "pump-around" up to a high enough speed to be effected by centrifugal forces. With out any safety features (seat back, safety harness) you should probably limit use to younger children in the 5 to 8 year old range, or add some of the mentioned safety features.

Growing up I didn't know to many kids who didn't have a BB gun or pellet gun at some time. I remember working my butt off, delivering fliers, to earn enough money ($52 back then for a nice solid wood stock break-barrel) to buy one when I was 13. I remember taking a back trail, to a remote lake out of town, one fall, to hunt grouse and do some target practice. I was doing some target practice at the lake, when two hunters with scary looking Winchesters in their hands, come walking down the trail. One guy commented on my "ineffective pellet gun" the other guy suggested to the big mouth that we see who can hit a pop can target about 40-50 feet away. I went first and nailed the pop can, the mouthy one's ear splitting shot missed. He made some excuse for missing, and shot down my humble pellet gun again. The other guy gave him a sour look and said, "at least he can hit what he's aiming at", ha,ha,ha, I was relieved when they continued on down the trail.

As mentioned before, I haven't hunted since I was a kid, but I still own three pellet guns, that I like to do target practice in the back yard with, on warm summer days. In Canada an unlicensed air rifle must be below 500 fps, muzzle velocity. Most retail units claim to be 495 fps, some may be, but many are not, and are actually much less (that made in china problem again). Generally I can puncture 1/4" spruce plywood. Many years ago I purchased one that claimed to be 495 fps, but it would stick or bounce off 1/4" plywood, rather than puncture it. I made some modifications with a heavier spring and this seemed to do the trick, I could puncture the plywood.

The problem of course is, without testing it, I could have been illegal at that point. Don't come and get me, I no longer have it, lol. So here is an interesting and relatively easy method of checking muzzle velocity in BB and pellet guns.



As mentioned I still play around with target practice. I have three pellet guns that I play with, one is similar to the classic, solid wood stock, break-barrel, that I mentioned above, it's now made in China so the quality isn't quite there. The Beeman below is the most accurate I have, it's made in China now too, but for playing around in the back yard, the price was right.


So here is that pump-around I mentioned. Energetic kids can have alot of fun on one of these, but it might be wise to consider some of the safety mods I mentioned above.