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Post by Cwi555 on Jul 27, 2012 8:16:17 GMT -7
This thread is intended to dispel firearms myths. I will start the ball rolling with this. There has been a lot of back and forth regarding steel case ammo. Most of the arguments come back to the hardness of the brass/steel casings being near the same. Proponents of steel case ammo get their hackles up when some suggest that they are hard on extractors. Their usual answer falls back to the hardness, and about how the rifle/pistol chamber is always harder. They are trying to rope the wrong goat with that. From a hardness standpoint, there is no significant difference between the steel case and brass case. Where the difference lies is in surface roughness. It is enough that in most cases, it can be felt by hand, much less detected by profilometer. en.wikipedia.org/wiki/ProfilometerThe surface of steel cases have a rougher surface than the brass variant. Even for those rounds that have a polymer coating, it's still rougher as the first thing to go is that coating while the spent casing is being extracted. If you put your firearm of choice in a vice, put a high speed camera to record and time it, you will find about ~ 2-5 millisecond delay in the extraction of casings between the brass and the steel. Thats not much time obviously. However, if you compare that time to the rise time and time at peak pressure for any given round, you will realize that is a very significant amount of time relative to the primer ignition to exit of the bullet. What that means to your extractor is more work. It also means more work to the entire system, springs included. If for instance you are shooting an AR15, you will have a spring underneath the extractor and likely a rubber buffer as well. That part of the system remains under pressure for longer per round as well. x unit of time, y unit of pressure = z unit of stress on the extractor. Its simple math. Increase either x or Y and you increase stress. It doesn't have a thing to do with hardness. If your going to shoot steel case ammo, I suggest you both keep it out of the weather (reference Wills thread on that one), and keep a supply of extractors/springs along with a broken head extractor. |
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Post by woodyz on Jul 27, 2012 16:08:08 GMT -7
edit: removed by popular demand.
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Post by thywar on Jul 27, 2012 16:31:50 GMT -7
Edited; please keep political comments in the appropriate section.
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Post by hunter63 on Jul 27, 2012 16:46:42 GMT -7
This thread is intended to dispel firearms myths. I will start the ball rolling with this. There has been a lot of back and forth regarding steel case ammo. Most of the arguments come back to the hardness of the brass/steel casings being near the same. Proponents of steel case ammo get their hackles up when some suggest that they are hard on extractors. Their usual answer falls back to the hardness, and about how the rifle/pistol chamber is always harder. They are trying to rope the wrong goat with that. From a hardness standpoint, there is no significant difference between the steel case and brass case. Where the difference lies is in surface roughness. It is enough that in most cases, it can be felt by hand, much less detected by profilometer. en.wikipedia.org/wiki/ProfilometerThe surface of steel cases have a rougher surface than the brass variant. Even for those rounds that have a polymer coating, it's still rougher as the first thing to go is that coating while the spent casing is being extracted. If you put your firearm of choice in a vice, put a high speed camera to record and time it, you will find about ~ 2-5 millisecond delay in the extraction of casings between the brass and the steel. Thats not much time obviously. However, if you compare that time to the rise time and time at peak pressure for any given round, you will realize that is a very significant amount of time relative to the primer ignition to exit of the bullet. What that means to your extractor is more work. It also means more work to the entire system, springs included. If for instance you are shooting an AR15, you will have a spring underneath the extractor and likely a rubber buffer as well. That part of the system remains under pressure for longer per round as well. x unit of time, y unit of pressure = z unit of stress on the extractor. Its simple math. Increase either x or Y and you increase stress. It doesn't have a thing to do with hardness. If your going to shoot steel case ammo, I suggest you both keep it out of the weather (reference Wills thread on that one), and keep a supply of extractors/springs along with a broken head extractor. Do have a reference for this? Are we talking unneeded wear?, ......higher pressures? Not trying to give you a bad time just curious. Spare parts are always a good thing, no matter what. |
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Post by wtrfwlr on Jul 27, 2012 16:50:01 GMT -7
I was hoping this would be a thread about guns and stuff like that where I could learn some things, not about politics? But it's not my thread so......
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Post by geron on Jul 27, 2012 16:53:03 GMT -7
Well, It may well end up that way anyway . . . hopefully.
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Post by Cwi555 on Jul 27, 2012 17:13:46 GMT -7
This thread is intended to dispel firearms myths. I will start the ball rolling with this. There has been a lot of back and forth regarding steel case ammo. Most of the arguments come back to the hardness of the brass/steel casings being near the same. Proponents of steel case ammo get their hackles up when some suggest that they are hard on extractors. Their usual answer falls back to the hardness, and about how the rifle/pistol chamber is always harder. They are trying to rope the wrong goat with that. From a hardness standpoint, there is no significant difference between the steel case and brass case. Where the difference lies is in surface roughness. It is enough that in most cases, it can be felt by hand, much less detected by profilometer. en.wikipedia.org/wiki/ProfilometerThe surface of steel cases have a rougher surface than the brass variant. Even for those rounds that have a polymer coating, it's still rougher as the first thing to go is that coating while the spent casing is being extracted. If you put your firearm of choice in a vice, put a high speed camera to record and time it, you will find about ~ 2-5 millisecond delay in the extraction of casings between the brass and the steel. Thats not much time obviously. However, if you compare that time to the rise time and time at peak pressure for any given round, you will realize that is a very significant amount of time relative to the primer ignition to exit of the bullet. What that means to your extractor is more work. It also means more work to the entire system, springs included. If for instance you are shooting an AR15, you will have a spring underneath the extractor and likely a rubber buffer as well. That part of the system remains under pressure for longer per round as well. x unit of time, y unit of pressure = z unit of stress on the extractor. Its simple math. Increase either x or Y and you increase stress. It doesn't have a thing to do with hardness. If your going to shoot steel case ammo, I suggest you both keep it out of the weather (reference Wills thread on that one), and keep a supply of extractors/springs along with a broken head extractor. Do have a reference for this? Are we talking unneeded wear?, ......higher pressures? Not trying to give you a bad time just curious. Spare parts are always a good thing, no matter what. The reference is my own work. I am talking some higher pressures but not dangerous levels. The rounds work just fine, but they do produce accelerated wear rates for the reasons I detailed above. |
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Post by Cwi555 on Jul 27, 2012 17:15:47 GMT -7
This thread is intended to be about firearms only. Please place political content in the general discussion section.
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Post by woodyz on Jul 27, 2012 17:16:18 GMT -7
I was hoping this would be a thread about guns and stuff like that where I could learn some things, not about politics? But it's not my thread so...... DONE |
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Post by woodyz on Jul 27, 2012 17:18:32 GMT -7
This thread is intended to be about firearms only. Please place political content in the general discussion section. Removed |
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Post by randyt on Jul 27, 2012 17:18:46 GMT -7
I have heard that corrosive primers are longer lasting and more reliable than standard primers. I have also heard that it makes no difference. What is the truth?
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Post by Cwi555 on Jul 27, 2012 17:25:24 GMT -7
I have heard that corrosive primers are longer lasting and more reliable than standard primers. I have also heard that it makes no difference. What is the truth? I don't think what we consider standard primers have been out long enough to make a definitive call on that given that there are millions of corrosive rounds in excess of 75 years old still going bang. |
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Post by randyt on Jul 27, 2012 17:28:33 GMT -7
Good point, I have some old pinfire rounds that will still go bang.
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Post by hunter63 on Jul 27, 2012 17:43:06 GMT -7
Good point, I have some old pinfire rounds that will still go bang. Why am I not surpried at that....LOL |
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Post by randyt on Jul 27, 2012 18:02:05 GMT -7
LOL What's happened is there has been generations of gun nutz in my family. Junk has been passed on to the younger generation. Unbelievably every generation has kept all this junk and the pile just keeps getting bigger and bigger. LOL.
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