PELLET TESTING BALLISTIC RESULTS Before we get onto the two chronograph tests that I carried out, we are first going to look at the plaster cores that I obtained. Pellet Entry wound size Maximum cavity diameter Cavity length AA Field Diabolo 25.9mm 25.9mm >100mm Power-force Sport 33.7mm 33.7mm 90.8mm JSB Polymag 31.4mm 31.4mm 87.5mm JSB Hades 24.8mm 28.7mm 71.4mm because the totality of the energy within the pellet has been surrendered within the quarry, but this has to be considered in combination with the other factors. The Polymag and the Sport are ballistically very close, but if I had to pick a winner to proceed to the next round of testing, and I do, I’m going to go with the Polymag, the reason for this simply being its superior accuracy. As you can see, with the exception of the Hades, most pellets achieved their maximum cavitation at the moment of impact, the cavitation size decreasing thereafter. The Hades did cause slightly more cavitation within the wound tract, but overall the results were less impressive than the Polymag and the Sport. To help us understand this, it’s important to note that when looking at cavity length, shorter generally means better expand the skirts. Does this matter? Will the skirts expand to a degree as they accelerate into the resistance of the air as they progress up the barrel? To be honest, I haven’t a clue. CHRONOGRAPH RESULTS Velocity lost (fps) Energy Lost (ft.lbs.) AA Diabolo: reverse load 284.8 7.15 SECOND SKIRT? AA Diabolo: conventional load 204 6.34 What I have seen that might help to explain the results obtained from the Polymag is that it almost has a second skirt resulting from the hollowed cavity which necessitates the accommodation of the plastic tip, and what can’t be denied is that the Polymag was the only pellet that flew backwards, yet perfectly straight into the wax. It’s also blindingly obvious that although a reverse-load domed pellet does perform ballisically better than a conventional load, it’s not even close to beating a modern pellet which has been specifically designed to expand on impact. JSB Polymag: reverse load 368 8.17 JSB Polymag: conventional load 404.4 9.73 From the above figures we can see that the domed pellet, when fired backwards, does indeed give better ballistic performance than when fired conventionally, but the performance of the Diabolo, and the Polymag in reverse are no match for the JSB Polymag when it is fired conventionally. DON’T FORGET … look into, then please don’t hesitate to contact the magazine and I’ll do the very best I can to research and deliver. As always, if you happen to have any other ideas or if there are theories you’d like me to I 49 www.airgunshooting.co.uk AIRGUN WORLD
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