Unofficial technical weapon question forum.
- Thread starter Scythe
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As for kB!s in polyagonally rifled pistols, another suspected cause is bullet set-back. Chambering a round multiple times can push the bullet back in the case; this can increase pressure when the round is set off. With the tighter chamber in a polyagonally rifled pistol (glocks, usp's), the pressures can increase much more quickly, leading to catastrophic failure (kaboom! or kB! for short). One of the theories was that it is in part due to the fact that Glock chambers are not fully supported, but I doubt that's the case since there have been a number of documented USP kb!'s, and the USP does have a fully supported chamber. It seems that this happens more frequently with .40 s&w than other calibers, as well - perhaps this caliber tends towards higher pressures? I haven't checked into that myself....
IIRC, Winchester and other ammo manufacturers suggest not chambering a round more than twice to prevent excessive setback. Personally, (especially since I carry a usp .40c) I always rotate my ammo - each round gets to be in the chamber once - when each round (or most of them) in the mag gets a turn in the chamber, they all get emptied into the range pile and fresh cartridges go in. Also, I'm pretty anal about cleaning and only shoot FMJ in my USP. Although for that matter, aside from various JHP's (which I'm considering), I don't think I've ever seen anything but FMJTC in .40s&w... Gryphon?
As for the supressor/silencer debate:
IIRC, Winchester and other ammo manufacturers suggest not chambering a round more than twice to prevent excessive setback. Personally, (especially since I carry a usp .40c) I always rotate my ammo - each round gets to be in the chamber once - when each round (or most of them) in the mag gets a turn in the chamber, they all get emptied into the range pile and fresh cartridges go in. Also, I'm pretty anal about cleaning and only shoot FMJ in my USP. Although for that matter, aside from various JHP's (which I'm considering), I don't think I've ever seen anything but FMJTC in .40s&w... Gryphon?
As for the supressor/silencer debate:
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I have seen both blown Glocks and USP's, so no doubt it can happen, best thing you can do the way i see it is to make sure you dont chamber multiple times, and only buy standard factory ammo (not a problem for me as thats pretty much all i can get currently), untill they fully know why this happens, you might aswell try to play it safe and belive the theory to be true.
Yes Dupre, I know that APFSDS rounds exist for rifled guns, it's just that smoothbore guns are much more suited for firing them - they are capable of achieving much higher velocities with much less barrel wear, and that's precisely what's needed for KE rounds, as they require muzzle velocity to be as high as possible.
I've seen solid lead TC in .40 S&W. If I'm not mistaken Federal offers it in their economy American Eagle line... Yep. 180 grain high-antimony lead at 990 fps. FWIW my "experience" with a Glock came in the form of .45 ACP SWC reloads. Don't care to destroy my hands like that again.
WRT the silencer/suppressor issue, there doesn't seem to be a well-established consensus anywhere. Call it what you want, but I'm sticking to my definition.
WRT the silencer/suppressor issue, there doesn't seem to be a well-established consensus anywhere. Call it what you want, but I'm sticking to my definition.
The point is the shift to smoothbore was to benefit HEAT. KE rounds are better off with rifled bores because rifled is more accurate than any smoothbore.
On the blown Glocks and USP's? if so, its not really 100% sertain what causes it yet, the most plausable theory at the moment is that when you chamber a round more than once, the projectile might be pushed further into the casing, adding more preasure to the charge, and that might cause more preasure than the chamber can handle.
But it remains a theory for now, it has yet to be prooven or disprooven...you cant really say its the round or the gun, its a combination i guess
glock/USP kB!
Yeah, the setback thing is the most plausible thing I've heard regarding factory ammo. Using reloads, the pressure may have been to high to begin with, so again, stick with factory loads of a type reccomended by the gun manufacturer, and rotate your ammo.
Jaunty, the idea of a bullpup going kB! is downright scary!
Yeah, the setback thing is the most plausible thing I've heard regarding factory ammo. Using reloads, the pressure may have been to high to begin with, so again, stick with factory loads of a type reccomended by the gun manufacturer, and rotate your ammo.
Jaunty, the idea of a bullpup going kB! is downright scary!
isn't that why the chamber has an armored plate over it (at least the FAMAS has). Regardless what are the odds of a military rifle going kB! It's not like they use reloads that often.
Isn't that a quote from the space program?
The bit about the gear being built by the lowest bidder?
The bit about the gear being built by the lowest bidder?
That is true, but only in an ideal world. In a real world, however, the extremely high muzzle velocities of subcaliber KE rounds wear rifling down EXTREMELY fast, so you have to use smoothbore. Even with smoothbore, the barrel wear is very noticable - the 120mm Rheinmetall tank gun used by most modern tanks is good for 400 shots, then the barrel has to be replaced. Imagine what it would be like if it was rifled. My father was doing research in internal ballistics during WWII, he's telling me that battleship main caliber guns often required an overhaul after less than 50 shots - that is what forced a research into smoothbore weapons.
Hmmm, I've heard of a "concussion" grenade (no, not a flashbang) that is exactly like a frag grenade, except it doesn't generate shrapnel, or very little fragments, due to its case.
Does it actually exist and is that a correct description of it?
Does it actually exist and is that a correct description of it?
Blatantly stolen from www.fas.org
MK3A2 concussion offensive hand grenade
The MK3A2 offensive hand grenade, commonly referred to as the concussion grenade, is designed to produce casualties during close combat while minimizing danger to friendly personnel. The grenade is also used for concussion effects in enclosed areas, for blasting, or for demolition tasks. The shock waves (overpressure) produced by this grenade when used in enclosed areas are greater than those produced by the fragmentation grenade. It is, therefore, very effective against enemy soldiers located in bunkers, buildings, and fortified areas.
(1) Body -- fiber (similar to the packing container for the fragmentation hand grenade).
(2) Filler -- 8 ouunces of TNT.
(3) Fuze -- M206A1 or M206A2.
(4) Weight -- 15.6 ounces.
(5) Safety clip -- yes.
(6) Capabilities -- can be thrown 40 meters by average soldier. The MK3A2 has an effective casualty radius in open areas of 2 meters. Secondary missiles and bits of fuze may be projected as far as 200 meters from the detonation point.
(7) Color/markings -- black with yellow markings around its middle.
MK3A2 concussion offensive hand grenade
The MK3A2 offensive hand grenade, commonly referred to as the concussion grenade, is designed to produce casualties during close combat while minimizing danger to friendly personnel. The grenade is also used for concussion effects in enclosed areas, for blasting, or for demolition tasks. The shock waves (overpressure) produced by this grenade when used in enclosed areas are greater than those produced by the fragmentation grenade. It is, therefore, very effective against enemy soldiers located in bunkers, buildings, and fortified areas.
(1) Body -- fiber (similar to the packing container for the fragmentation hand grenade).
(2) Filler -- 8 ouunces of TNT.
(3) Fuze -- M206A1 or M206A2.
(4) Weight -- 15.6 ounces.
(5) Safety clip -- yes.
(6) Capabilities -- can be thrown 40 meters by average soldier. The MK3A2 has an effective casualty radius in open areas of 2 meters. Secondary missiles and bits of fuze may be projected as far as 200 meters from the detonation point.
(7) Color/markings -- black with yellow markings around its middle.
The KB's are being attributed to using lead bullets in the polygonal rifling. From glockmeister.com:
My experience was due to the ammunition. This happened over 5 years ago when this phenomena wasn't widely known. We had initially attributed it to a double charge, although since these were my dad's reloads done on a Dillon XL650 with a powder alarm, that was quickly written off. Years later, the ugly truth is revealed...