Bullets and Boomers
Although we had lots of hints over the years it wasn't until April 3, 2006 that we conclusively proved that the bullet shape made a big difference and quantified it with numbers. For years we wanted to believe that if we could set the boomers off with a .22LR bullet going a particular velocity then the boomers would detonate with the same diameter or larger bullet going the same velocity. This isn't true. We found this out in a very painful way during the Precision Rifle Clinic of Boomershoot 2005. The same targets that we could detonate with a .22LR from 15 yards away had multiple .30 caliber holes with bullets in excess of 2000 fps.
We did a series of tests in the Fall of 2005 and spring of 2006 on an improved mix:
We then measured the velocity difference for successful detonation with these two bullets:
The .22LR will reliable detonate the present mix (as of the spring of 2006) with a velocity of 1170 fps. The V-MAX bullet requires 1700 fps to get detonations 50% of the time. For the same probability of detonation it probably is a difference of 550 fps. At this velocity the V-MAX bullet does not expand in the boomerite targets.
We believe the difference is because of the flat point of the .22LR versus the very pointed tip of V-MAX. The flat point increases the compression of the air spaces between the particles of the explosive mix resulting in more heating for the same velocity.
What this means for the Boomershooter is that while a bullet with a good ballistic coefficient will retain more velocity it may also have a shape that doesn't detonate the targets as easily. A bullet with a flat tip with a lower target velocity may give better detonation. However, if you are delivering the bullet with a velocity of greater than 1700 fps it is expected that just about any bullet will detonate them.
Email: Joe Huffman