Questions about M855A1

[Todd.K]

There is no such thing as "overstabilized", a bullet either is or is not stabilized. There is a range we call marginal but that simply means it's within a change of ambient conditions of not being stabilized. The testing quite clearly discovered "fleet yaw" to be the reason for variable terminal performance.

I will not be missing any sleep over M855A1 being unavailable, there are plenty of good barrier blind options to choose from these days. Commie steel helmets at 300m isn't a major factor in my threat assessment.

[Iraqgunz]

Pretty much that.

There is no such thing as "overstabilized", a bullet either is or is not stabilized. There is a range we call marginal but that simply means it's within a change of ambient conditions of not being stabilized. The testing quite clearly discovered "fleet yaw" to be the reason for variable terminal performance.

I will not be missing any sleep over M855A1 being unavailable, there are plenty of good barrier blind options to choose from these days. Commie steel helmets at 300m isn't a major factor in my threat assessment.

[Hulkstr8]

Commie steel helmets at 300m isn't a major factor in my threat assessment.

*watches Red Dawn*

[okie]

I think I understand what you mean now. So why wasn't fleet yaw a problem with M193, but then suddenly it's a big problem with M855? I know I'm derailing the thread now, but I'm curious. And seeing as how we have until 2027 to discuss the finer points of M855A1...

[PappyM3]

I think I understand what you mean now. So why wasn't fleet yaw a problem with M193, but then suddenly it's a big problem with M855? I know I'm derailing the thread now, but I'm curious. And seeing as how we have until 2027 to discuss the finer points of M855A1...

How do you surmise that it hasn’t been a problem with M193? The problems with M855 were initially noticed because US forces in GWOT analyzed wounded/dead enemy combatants. Is there a similar analysis of M193 wounds available to either show(or not) intermittent ice picking? It’s also possible that M193 isn’t as dependent on yaw as M855 due to more dependable fragmentation in the bullet design, but there hasn’t been any experiment to show how much of an impact fleet yaw has on M193. The Army Research Laboratory radiograph testing, which demonstrated fleet yaw characteristics, was conducted in 2005-2006. As such, they used the current issued round for testing, the M855, to either substantiate or refute the observations in the theaters of combat. The report for the experiment is readily accessible and is a good read.

[Todd.K]

M193 also suffers fleet yaw.

"Testing demonstrated that 5.56 mm is highly susceptible to AOA variations, particularly when using military style FMJ projectiles such as M193 & M855."
https://www.m4carbine.net/showthread...27#post1151327

[okie]

How do you surmise that it hasn’t been a problem with M193? The problems with M855 were initially noticed because US forces in GWOT analyzed wounded/dead enemy combatants. Is there a similar analysis of M193 wounds available to either show(or not) intermittent ice picking? It’s also possible that M193 isn’t as dependent on yaw as M855 due to more dependable fragmentation in the bullet design, but there hasn’t been any experiment to show how much of an impact fleet yaw has on M193. The Army Research Laboratory radiograph testing, which demonstrated fleet yaw characteristics, was conducted in 2005-2006. As such, they used the current issued round for testing, the M855, to either substantiate or refute the observations in the theaters of combat. The report for the experiment is readily accessible and is a good read.

M193 also suffers fleet yaw.

"Testing demonstrated that 5.56 mm is highly susceptible to AOA variations, particularly when using military style FMJ projectiles such as M193 & M855."
https://www.m4carbine.net/showthread...27#post1151327

See this is making me think there really is something to the twist rates then, because all the reports from Vietnam were good as far as I've ever heard. And I have to think there were plenty of up close shots being in the jungle and all. Idk, I'm not enough of a physics buff to make my own opinions. I just wish M855A1 were commonly available and then I wouldn't have to think about such things. Uncle Sam finally gave us a cheap round that's worth a damn, then made sure we couldn't get it! Ornery old bastard...

[vicious_cb]

See this is making me think there really is something to the twist rates then, because all the reports from Vietnam were good as far as I've ever heard. And I have to think there were plenty of up close shots being in the jungle and all. Idk, I'm not enough of a physics buff to make my own opinions. I just wish M855A1 were commonly available and then I wouldn't have to think about such things. Uncle Sam finally gave us a cheap round that's worth a damn, then made sure we couldn't get it! Ornery old bastard...

You're still talking about this subject like its a mystery, as stated above we've showed you ample evidence that twist rate doesnt affect the terminal ballistics of these rounds yet you still refuse to believe it.

[Todd.K]

I don't think there is the same problem with MK318 and patents, yet it isn't readily available or cheap.

Vietnam had plenty of variable terminal performance complaints. I think it even started the twist theory as the first ones over there were 1/14" vs the 1/12" that became the standard issue.

When the whole angle/fleet yaw thing was discovered it proved the first hand accounts of both sides could be correct. It comes down to smaller calibers having less reliable yaw and fragmentation with ball. It's also the reason the experts say barrier blind expanding loads are more reliable than loads that rely on fragmentation, even the heavy OTM's.

[vicious_cb]

I don't think there is the same problem with MK318 and patents, yet it isn't readily available or cheap.

Vietnam had plenty of variable terminal performance complaints. I think it even started the twist theory as the first ones over there were 1/14" vs the 1/12" that became the standard issue.

When the whole angle/fleet yaw thing was discovered it proved the first hand accounts of both sides could be correct. It comes down to smaller calibers having less reliable yaw and fragmentation with ball. It's also the reason the experts say barrier blind expanding loads are more reliable than loads that rely on fragmentation, even the heavy OTM's.

Mk318 is yaw independent because it basically an unbonded trophy bonded bear claw. Follows the same hydraulic expansion mechanism as its hunting counterpart.