I think you're gonna have to test it with live bees ...
This reminds me of a story about some guys trying to sell 20mm explosive ammunition to the Army. Apparently, they were on the final leg of the approval process and had to demonstrate live fire in front of Army inspectors. They fired their 20mm test round, and a short distance in front of the gun it detonated in the air. Instant fail. No chance at the contract now, but if they could present evidence of why it wasn't the fault of the ammo, they could be reconsidered.
Upon scouring the slow-mo video for clues, someone spotted a bumble bee. Could it have flown into the bullet? Could that set it off? Only one way to find out. Out at the range, they have bees dangling from fishing line as they shoot at them with 20mm bullets. Can't seem to get the rounds to go off though. Bummer.
Then someone notes in the video, that it looks like two bees flew into each other. Could it be? So, back to the range with the 20mm gun, this time shooting at two bees at a time. Sure enough, it's enough mass to detonate the round each time. They had solved the mystery. After presenting the evidence to the Army, and demonstrating the "two bees hugging in front of the gun" effect, they supposedly passed and won the contract.
I don't know if this story is true, but I like it anyway.
