Some time ago I evaluated an experimental shot crusher from Stuart Crane at Clay Shooting Magazine in the UK. The crusher is basically a heavy steel dowel centered in a guide tube over a steel plate. The dowel is raised to a witness mark, a pellet is placed underneath the point of impact, and the dowel is released to fall 3″ and impact on the pellet. The motive power is pure gravity. The crusher is built of heavy steel and will last a millennium or two. The crusher was thoughtfully accompanied by a .0001″ digital micrometer.
Use of the device was simplicity itself (just as well). The micrometer is first used to measure the original diameter of the pellet. The pellet is then crushed and a new measurement taken on the “flats” of the crushed pellet. The “after” measurement is divided by the “before” measurement and subtracted from 1 to produce a percentage “crush” value. This level of mathematics is basic enough even for the Technoid to deal with.
In actual use, things were not quite as easy as they looked. Most shotgun pellets are not round, so two or three initial measurements and some averaging were required for most pellets before crushing. Measuring the flats after was easy. Due to the initial lack of roundness, the results are approximate, but probably pretty good anyway.
Here is what the surgically clean test laboratories produced on their first test batch. Seven examples of each pellet were tested. A lower percentage means less crush distortion and thus a harder pellet.
#8 Lawrence Magnum bagged shot 26%
#8 Remington Gun Club factory 30%
#8 Federal Xtra-Lite factory 31%
#8 Peruvian Magnum bagged shot 35%
#8 Victory 480 factory 41%
#7.5 Lawrence Magnum bagged shot 25%
#7.5 Remington STS factory 27%
#7.5 Victory 480 factory 30%
#7.5 Peruvian Magnum bagged shot 34%
What does this all prove? Not much yet. Cursory pattern tests have shown that the #7.5 Remington STS and Victory 480s pattern just about exactly the same (and very nicely, thank you), while reloads using the #7.5 Peruvian Magnum bagged shot had noticeably inferior patterns containing an average of 12% fewer pellet strikes. The crush tests of the #7.5s indicate that the Victory’s are in between the STS and Peruvian loads in hardness, but pattern quality does not reflect this. The Victorys produce excellent patterns, right in there with the benchmark STS shells. Perhaps Victory’s use of a superior powder or a clever wad design makes up for the difference in shot softness. Obviously, more experiments are in order, especially with the #8 sizes. Anyone want to volunteer to conduct some more tests? I thought so. Then you will just have to wait.