Bullet trap + chronograph

Buerste · 2009-07-20T07:40:17+00:00

I'm thinking of a trap or tank that I can test pistol loads. Imagine the kind you see on cop shows that they can test fire weapons. Look at: I'd like to incorporate a chronograph and be able to test pistol function in multiple shots. The unit will have to be quiet enough to keep the neighbors oblivious and the fumes will have to be vented. Has anyone seen plans for such? The cheapest commercial ones are thousands of $, and no chrony. It would seem the perfect way to work loads in a very short time.I was thinking of an automated computer controlled conveyer system to transport the empty shells through a cleaning cycle and back to the reloading press. The powder charge could be adjusted by computer to the desired FPS and the fresh reloads could be conveyed back to the test chamber. (just kidding)

Doug White 17 years ago

cavelamb wrote in news:E6udnd-vZr6PwvjXnZ2dnUVZ snipped-for-privacy@earthlink.com:

In another life, I taught a high speed photography course at MIT in Doc Edgerton's "strobe lab".

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That included bullet photography. A couple of things:

1) A regular xenon photoflash flash is WAY too long (and variable) to give a good image of even a .22 rimfire bullet. It also doesn't start & stop instantly. It ramps up, peaks, and then trails off slowly. We used a special "microflash" unit that used a 4 kV(?) air spark. 2) The triggering was done with a crystal microphone with the diaphram removed. Otherwise the shock wave would break the crystal. The shock wave off the bullet trails behind by a very repeatable amount for a given distance between the bullet path & the microphone. For a fixed velocity round, it didn't take too many shots to get a good photo.

As far as being practical for the bullet trap business, a flash would be tricky at best. You might actually be able to use a pair of the triggering mics instead of the usual optical system. As long as the mics were placed parallel to the bullets flight, it should work pretty well. You have to make sure the mics are closer to the bullet's path than to the muzzle, so the shock wave from the bullet hits them before the muzzle blast does.

Doug White

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Martin H. Eastburn 17 years ago

Steel plate vaporizes most bullets. I don't mean normal hot rolled metal. I use AR400 for rifle and pistol targets. I get a target to weld on new feet - they blow them off their feet on hot loads - there is round dots of lead. Copper in the trap or sand pit.

The trap is like a leaning, collapsing box. The bullet hits and if it has anything left, it is reflected (think pool balls) by the angle above to the angle below - so if at 45 degrees, it goes downwards.

It is possible if you are very close - 20 or so feet and fire into a flat hard surface that some back splatter might come at you.

Remember - this is not Armor plate bullets that split out a center of Tungsten and it goes haywire...

NRA and IHMSA (and others) shoot metallic targets on ranges every day. Many indoor ranges have diagonal bullet plates that drive the bullets into a sand trap on the floor.

Mart>> Blow off the junk bullet - let it smack into steel.

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RBnDFW 17 years ago

I have one of those $50 .22 traps that is a miniature of this. At 10-ft I get splatter back. The paper is riddled with tiny holes coming back out. I decided to move back a bit.

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