Total Detonation

[OldLincoln]

I need some words about the following re Total Detonation or KaBoom.

Total Detonation (http://www.thefirearmsforum.com/showthread.php?p=685113#post685113)

"On some rare instances, total detonation of the powder charge occurred upon pulling the trigger causing devastating results to the firearm and injury to the shooter. Initial opinion was that there was (by mistake) a double charge in the cartridge. This eventually was dismissed due to the fact that the cartridge cases involved could not hold a second charge. It is a known fact that fast burning light loads in large capacity cases are subject to excessive pressures when fillers are not used, but the referenced above were full or near full charges using medium and slower burning powders."

"Too small an amount of powder in any burn rate will detonate. The worst is slow burning powders in small amounts."
================================

I read somewhere that there are prescribed headspace requirements for loads. I thought the kb's from set-back bullets were because there was too little headspace, now I'm confused. (Perhaps I should change my location to "The State of Confusion.")

Your thoughts?

[Bawanna]

I need some words about the following re Total Detonation or KaBoom.

Total Detonation (http://www.thefirearmsforum.com/showthread.php?p=685113#post685113)

"On some rare instances, total detonation of the powder charge occurred upon pulling the trigger causing devastating results to the firearm and injury to the shooter. Initial opinion was that there was (by mistake) a double charge in the cartridge. This eventually was dismissed due to the fact that the cartridge cases involved could not hold a second charge. It is a known fact that fast burning light loads in large capacity cases are subject to excessive pressures when fillers are not used, but the referenced above were full or near full charges using medium and slower burning powders."

"Too small an amount of powder in any burn rate will detonate. The worst is slow burning powders in small amounts."
================================

I read somewhere that there are prescribed headspace requirements for loads. I thought the kb's from set-back bullets were because there was too little headspace, now I'm confused. (Perhaps I should change my location to "The State of Confusion.")

Your thoughts?

Don't get overwrought buddy. Bullet set back and headspace are different issues. A 45 and a 9 or any rimless round headspaces on the case rim or mouth. A 357 or 44 etc headspaces on the rim. This is what holds the case in the right place. A bottleneck cartridge headspaces on the shoulder of the case. There are more issues there to deal with.
Bullet set back is just decreasing the amount of space the powder has to work in increasing the pressure.
All this is where the factory crimp die is nice especially on a rimless round like the 45, it give you a good tapered crimp so the bullet is tight but won't allow too much crimp so the case isn't supported as it should be.

[Replay13]

Hello, and interesting subject,

I guess we all have our own theorys about stuff, and I have mine too, lol. Acually I think Glocks in .40 cal had most of the problems for two reasons. First the .40 is a high pressure round and second Glock cut out the bottom part of the barrel to help assist in feeding (that left a small part of the cartridge case unsupported just ahead of the case web. Also the .40 has a pretty small case web to start with. But that being said it all works pretty good if they don't shoot reloads. Do a google search on Glock barrels and you will find a pictures to better explain what I'm talking about. I see where a lot of the Glock shooters replace the barrel for reloading and shooting competition.

There is other reasons that can explain the Ka-booms. Guns that fire out of battery (being able to fire just before the cartridge is fully locked up) can cause a problem with a high pressure round like the .40 I don't think you will find this happening very often with a round like the .45.

OK and like you said there is some slow burning powders that need a tight crimp and magnum primers to burn properly. But those powders are used more for magnum pistols. Also there is a serious problem with bullet setback with our autos (no roll crimp) and this can cause a big problem with over pressure... especially with fast powders and the heaver bullets. Anyone reloading and over taper crimping a bullet (this makes it looser in the case, the bullet sizes down and the case springs back) can have bullet setback especially with a harder recoiling rounds like the .40. Also repeated chambering of a round will cause bullet setback. I got a box of 125 gr bullets for reloading in .40 from a notable bullet manufacture and after some testing I would never shoot them! Being a really light bullet for .40 cal they didn't have much bearing surface for the case to grip and would setback 5 to 10 thousands just just chambering!

Well as you can tell I don't own any Glocks and they are good guns... most of our local finest here carry Glocks. But I do have a 40 S&W that I really like and I load for it and feel safe. There is a lot of good 40's out there but mine is a XDM. It is the gun that I carry out hiking, it has as much power as my .357 snubby and carries three times the rounds and is even pleasant to shoot! That .357 snubby that I have kicks worse then any pistol that I have ever shot! lol. I can shoot it ok, but I will have some blood somewhere if I shoot 50 rounds.

Ok, just my thoughts and some more.. lol
James (Replay13)