Very interesting experiment. I scratched my head trying to figure out why the hell it didn’t blow up while reading this.
I have a suggestion for another test regarding catastrophic failures:
It is often said that old ammo might encounter issues when it was exposed to adverse conditions. The moisture etc might cause the propellant to stick together at an odd angle in the case, causing a modified pressure spike. Sometimes you see people suggesting you should shake old ammo to see if you can still hear the grains inside, to make sure it’s not cluttered together.
From what I understand, one of the theories of why this is dangerous is that due to the propellant sticking together, you step away from the standard ignition of powder going back to front. If the powder is cluttered together at the bottom of the case, your primer might cause ignition that causes an upward pressure spike. Putting excess strain on the chamber.
Related to this is the danger of underloading, for the same reason. If the primer pocket is above the propellant, the rate at which powder grains catch fire will travel across the case fast, while underlying propellant will catch fire slower. This creates an upward pressure spike, instead back to front. That makes underloading just as dangerous as overloading.
I would have to agree with GVD. I remember during my ar15/M16 armorer training the instructor did a presentation on bullets/case characteristics/head spacing etc…He warned us that most KB with the ar15/M16 platform was due to underloaded cases. All the powder would ingnite at roughly the same time causing a huge pressure spike.
It split the frame in two in the middle from the back of the magwell to the front of the dust cover and EVERYTHING was destroyed. I outlined it on my FB page. To say the least, it was quite impressive that it broke it that bad and that I wasn’t seriously hurt in the process.
I’ve heard about this happening to the 40cal Glocks and their unsupported chambers but even then everything I’ve seen wasn’t nearly as bad as what I had. The only thing we can think of is that I double charged the load (normal load is 4.2gr of Titegroup with a Montana Gold 124gr HP). We’re thinking that once you seated a bullet on top of 8.4gr that it would compress the load leading to even higher pressures. This is what we’re thinking had to have happened but truthfully I don’t know. That would have had to be it based on the total destruction of the pistol but it does appear to have been partially unlocked by as much as 1/64″ when it let go based on the case. Maybe it unlocked and unchambered as it blew apart because there is no way that it would have ever let the striker loose that much out of battery.
Have you thought about doing a test to over charge a round up to a double charge to see what it would do to the pistol? I’m wondering what would have happened had I been using an aluminum frame Sig instead of a Glock. Would it have held or what I need to go the the ER to pick out metal from my body?
On purpose? I would think a steel frame would hold up a bit different and the case of 45 would have more space available without the resultant pressure increase of a smaller case I would think.
Yes, I would absolutely love to see more about this.
Have you simulated setback in QuickLoad? I have the program, send me an email if I can crunch some numbers for you.
You should try this on an early generation Glock.
Hey Andrew,
Very interesting experiment. I scratched my head trying to figure out why the hell it didn’t blow up while reading this.
I have a suggestion for another test regarding catastrophic failures:
It is often said that old ammo might encounter issues when it was exposed to adverse conditions. The moisture etc might cause the propellant to stick together at an odd angle in the case, causing a modified pressure spike. Sometimes you see people suggesting you should shake old ammo to see if you can still hear the grains inside, to make sure it’s not cluttered together.
From what I understand, one of the theories of why this is dangerous is that due to the propellant sticking together, you step away from the standard ignition of powder going back to front. If the powder is cluttered together at the bottom of the case, your primer might cause ignition that causes an upward pressure spike. Putting excess strain on the chamber.
Related to this is the danger of underloading, for the same reason. If the primer pocket is above the propellant, the rate at which powder grains catch fire will travel across the case fast, while underlying propellant will catch fire slower. This creates an upward pressure spike, instead back to front. That makes underloading just as dangerous as overloading.
Or that’s what I’ve been told anyway.
Something to look into?
Best regards,
GVD
I may indeed conduct further experiments. Thanks.
I would have to agree with GVD. I remember during my ar15/M16 armorer training the instructor did a presentation on bullets/case characteristics/head spacing etc…He warned us that most KB with the ar15/M16 platform was due to underloaded cases. All the powder would ingnite at roughly the same time causing a huge pressure spike.
Nice article Andrew.
Hope this finds everyone well!
So last week at a USPSA match I had one hell of an epic KABOOM with my G34. https://www.youtube.com/watch?v=sQEEYNC3YmU
It split the frame in two in the middle from the back of the magwell to the front of the dust cover and EVERYTHING was destroyed. I outlined it on my FB page. To say the least, it was quite impressive that it broke it that bad and that I wasn’t seriously hurt in the process.
I’ve heard about this happening to the 40cal Glocks and their unsupported chambers but even then everything I’ve seen wasn’t nearly as bad as what I had. The only thing we can think of is that I double charged the load (normal load is 4.2gr of Titegroup with a Montana Gold 124gr HP). We’re thinking that once you seated a bullet on top of 8.4gr that it would compress the load leading to even higher pressures. This is what we’re thinking had to have happened but truthfully I don’t know. That would have had to be it based on the total destruction of the pistol but it does appear to have been partially unlocked by as much as 1/64″ when it let go based on the case. Maybe it unlocked and unchambered as it blew apart because there is no way that it would have ever let the striker loose that much out of battery.
Have you thought about doing a test to over charge a round up to a double charge to see what it would do to the pistol? I’m wondering what would have happened had I been using an aluminum frame Sig instead of a Glock. Would it have held or what I need to go the the ER to pick out metal from my body?
I fired a double charge of Titegroup in a .45 1911 once, it didn’t blow up…but different caliber, load, environmental conditions etc.
On purpose? I would think a steel frame would hold up a bit different and the case of 45 would have more space available without the resultant pressure increase of a smaller case I would think.
The frame doesn’t contain pressure, it doesn’t affect the likelihood of a catastrophic failure in any way.