Other than a prodigious waste of ammo, I’m not sure what that proved, outside of the fact that the dude behind the gun is lucky it didn’t blow up in his face.
It’s not a bad idea to know the limits of the system. All sorts of companies use destructive testing. It’s part of SOP. I do it sometimes. New vehicles are smashed on a regular basis, not just by manufacturers, but by insurance companies.
The thing didn’t blow up, so I wouldn’t conclude from the video alone that it failed from heat only. It may have gotten too dirty, worn, had a spring or an extractor break…
It did slow down right before it stopped, FWIW, which is ineteresting. Normally I’d have said that wouldn’t happen because the rate of fire is determined by the mechanism’s natural period. But I suppose any mechanical resonance can be tweaked a bit either direction as the parts change in some way. In music we call it pitch vibrato, or pitch bending, or playing out of tune.
I call the slowdown “drag”. By that point the lubricants have probably burnt off all the bolt and track surfaces and the bolt and chamber will be growing… until eventually the gas system doesn’t produce enough force to overcome it.
To be honest though, I was expecting catastrophic barrel failure…. heating past the critical temp, barrel droops, projectiles blow through the side….
April 13th, 2009 at 2:12 pm
Other than a prodigious waste of ammo, I’m not sure what that proved, outside of the fact that the dude behind the gun is lucky it didn’t blow up in his face.
April 13th, 2009 at 2:31 pm
“I’m not sure what that proved”
I think they were demonstrating one of the more expensive ways to create a smoothbore barrel.
April 13th, 2009 at 10:58 pm
It’s not a bad idea to know the limits of the system. All sorts of companies use destructive testing. It’s part of SOP. I do it sometimes. New vehicles are smashed on a regular basis, not just by manufacturers, but by insurance companies.
The thing didn’t blow up, so I wouldn’t conclude from the video alone that it failed from heat only. It may have gotten too dirty, worn, had a spring or an extractor break…
It did slow down right before it stopped, FWIW, which is ineteresting. Normally I’d have said that wouldn’t happen because the rate of fire is determined by the mechanism’s natural period. But I suppose any mechanical resonance can be tweaked a bit either direction as the parts change in some way. In music we call it pitch vibrato, or pitch bending, or playing out of tune.
April 13th, 2009 at 11:15 pm
I call the slowdown “drag”. By that point the lubricants have probably burnt off all the bolt and track surfaces and the bolt and chamber will be growing… until eventually the gas system doesn’t produce enough force to overcome it.
To be honest though, I was expecting catastrophic barrel failure…. heating past the critical temp, barrel droops, projectiles blow through the side….
April 14th, 2009 at 12:22 pm
Exactly, Dr.. Which is why I don’t think I would want to be snuggled up against the gun in question.
It WOULD have been interesting to know why it stopped – it could have been just a dud round, since the dude didn’t even attempt to get it going again.
I noted a couple of places where the cyclic rate changed, up & down, though that might have just been an artifact of the video.