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chrome lined VS stainless steel (AR15)
l3to
Member Posts: 256 ✭✭✭
Could some one give me a quick run down of the difference between a stainless steel barrel and chrome lined? I am less concerned with the molecular structure and more concerned with the practical differences.
Some extra info, it's for an AR15 and it's a 20".
Thanks!
Some extra info, it's for an AR15 and it's a 20".
Thanks!
Comments
The chrome lining is there to resist wear and corrosion. However, most commercial chrome lined bores have a thickness of 0.0005 to 0.00075 inches of chrome. It is very difficult to control the tolerances of the bore when chrome lining because it is plated onto the barrel steel. While the chrome is good for preventing corrosion and some metal fouling, it is not good for accuracy and the chrome plating will wear out. Chrome plating the bore will not increase velocity either.
Stainless steel is a strange beast because of its different varieties which impart different properties. What gives stainless some of its best properties is at least a 10% chrome content. Generally, stainless has some very favorable properties such as wear resistance, corrosion resistance, and resists high temperature scaling. To attain the proper tensile strength for firearms, the stainless formula must be altered which can allow rust and corrosion. An important note is that stainless steel is brittle and will sheer under temperature extremes or if not heat treated properly. There is a major premium after market rifle barrel manufacturer who recommends their stainless steel barrels not to be fired when temperatures approach -40F. Due to the toughness of the stainless it is also difficult to machine which can cause problems with rifling, reaming, etc.
Chromemoly steel is the most commonly used steel for firearms and is probably the most durable. 4140 S.A.E. grade is considered an ultra high strength steel and if properly heat treated can attain a tensile strength of 180,000 psi. Plain-jane cold drawn and annealed chromemoly can attain a tensile strength of 98,000 psi.
The idea here is to remember that each material has its own merits and disadvantages. How you intend to use your firearm and under what conditions should guide your selection of a barrel material.
Regards,
Heavyiron
Hi,
The chrome lining is there to resist wear and corrosion. However, most commercial chrome lined bores have a thickness of 0.0005 to 0.00075 inches of chrome. It is very difficult to control the tolerances of the bore when chrome lining because it is plated onto the barrel steel. While the chrome is good for preventing corrosion and some metal fouling, it is not good for accuracy and the chrome plating will wear out. Chrome plating the bore will not increase velocity either.
Stainless steel is a strange beast because of its different varieties which impart different properties. What gives stainless some of its best properties is at least a 10% chrome content. Generally, stainless has some very favorable properties such as wear resistance, corrosion resistance, and resists high temperature scaling. To attain the proper tensile strength for firearms, the stainless formula must be altered which can allow rust and corrosion. An important note is that stainless steel is brittle and will sheer under temperature extremes or if not heat treated properly. There is a major premium after market rifle barrel manufacturer who recommends their stainless steel barrels not to be fired when temperatures approach -40F. Due to the toughness of the stainless it is also difficult to machine which can cause problems with rifling, reaming, etc.
Chromemoly steel is the most commonly used steel for firearms and is probably the most durable. 4140 S.A.E. grade is considered an ultra high strength steel and if properly heat treated can attain a tensile strength of 180,000 psi. Plain-jane cold drawn and annealed chromemoly can attain a tensile strength of 98,000 psi.
The idea here is to remember that each material has its own merits and disadvantages. How you intend to use your firearm and under what conditions should guide your selection of a barrel material.
Regards,
Heavyiron
Thanks! that helps alot. I am looking for more of accuracy than anything.
thanks again