Chrome Lined Barrels
- Thread starter John S
- Start date
G
gt40
Guest
The WSSMs from Winchester & Browning were chrome lined to increase barrel life. How it is done 
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gt40
.gt40
O
Old Gunner
Guest
M14 barrels were chromelined mainly to allow use of the cheaper to produce but much hotter burning Double Base Ball propellants in use at the time. More modern Ball Propellant formulas include temperature moderators and coolants but still erode unprotected bore steel due to the heavier molecular weight of gases of combustion.
M14 barrels manufactured without Chrome lining are a bit more accurate so the Sniper rifle version of the M14 used unlined barrels. Match ammunition loaded with Single Base powders were generally used for Sniping as well as long range match shooting so the Chrome lining was un necessary.
The more recent US Military sniper rifles use a Martensitic Stainless Steel alloy barrel that holds up well to the slightly higher erosion of modern Ball Powders. The rifling used is of a special design intended to reduce the effects of erosion and gas blow by. Together these improvements allow a greatly extended accuracy life.
Cromelining and Stelite inserts at chamber and throat allow a long useful bore life for semi auto and full auto weapons.
Plated bores are also less prone to corrosion, but this is more a beneficial side effect, reduced erosion is the primary reason for going to the extra expense of chromelining since the introduction of non corrosive primers.
M14 barrels manufactured without Chrome lining are a bit more accurate so the Sniper rifle version of the M14 used unlined barrels. Match ammunition loaded with Single Base powders were generally used for Sniping as well as long range match shooting so the Chrome lining was un necessary.
The more recent US Military sniper rifles use a Martensitic Stainless Steel alloy barrel that holds up well to the slightly higher erosion of modern Ball Powders. The rifling used is of a special design intended to reduce the effects of erosion and gas blow by. Together these improvements allow a greatly extended accuracy life.
Cromelining and Stelite inserts at chamber and throat allow a long useful bore life for semi auto and full auto weapons.
Plated bores are also less prone to corrosion, but this is more a beneficial side effect, reduced erosion is the primary reason for going to the extra expense of chromelining since the introduction of non corrosive primers.
O
OldPPC
Guest
I've always understood that chrome barrels are actually made from chromium steel rather than being hard chrome plated. Hard chrome plating is thicker than decorative chrome plating and it's applied using electro-plating but I can't imagine electro-plating the inside of a rifle barrel without chroming the entire barrel inside and out.
Chrome Plated Rifle Bores
This is a better term.
Being they are military barrels they must be hammer forged.
How do they do it without constricting the bore and maintaining acceptable accracy?
I did an internet search and didn't find much info on small arms.
Sometimes I wish I never thought about some stuff=
This is a better term.
Being they are military barrels they must be hammer forged.
How do they do it without constricting the bore and maintaining acceptable accracy?
I did an internet search and didn't find much info on small arms.
Sometimes I wish I never thought about some stuff
=Chrome-lined barrels...
are, indeed, plated with hard industrial chromium.
The process requires an electrode of a form which is the reverse of the rifled bore, in order to prevent plating of uneven thickness caused by varying distance from the electrode to the bore surface - needless to say the quality of the plating depends on accurate orientation and centering of the electrode in the bore. It is also necessary to dimension the finish-rifled bore to allow for the thickness of plating while remaining within permissible tolerances.
Others have given the reasons why such plating is useful in military barrels: these hardly apply to civilian use, since civilians do not (usually) subject their arms to the extremes of environment experienced in military hands, nor do they often engage in extended periods of rapid fire or full-auto fire.
Examination of the interior of plated barrels will show that the surface finish is usually not so good as in an un-plated bore: neither is the average accuracy. When chromed barrels DO fail, they usually do so by cracking and flaking-off of the plating in the throat, extending progressively forward with further use: when this happens, that barrel is done, so far as accuracy goes.
If your requirement is for best accuracy, rather than endurance of extreme conditions, a non-plated barrel is the best choice.
mhb - Mike
are, indeed, plated with hard industrial chromium.
The process requires an electrode of a form which is the reverse of the rifled bore, in order to prevent plating of uneven thickness caused by varying distance from the electrode to the bore surface - needless to say the quality of the plating depends on accurate orientation and centering of the electrode in the bore. It is also necessary to dimension the finish-rifled bore to allow for the thickness of plating while remaining within permissible tolerances.
Others have given the reasons why such plating is useful in military barrels: these hardly apply to civilian use, since civilians do not (usually) subject their arms to the extremes of environment experienced in military hands, nor do they often engage in extended periods of rapid fire or full-auto fire.
Examination of the interior of plated barrels will show that the surface finish is usually not so good as in an un-plated bore: neither is the average accuracy. When chromed barrels DO fail, they usually do so by cracking and flaking-off of the plating in the throat, extending progressively forward with further use: when this happens, that barrel is done, so far as accuracy goes.
If your requirement is for best accuracy, rather than endurance of extreme conditions, a non-plated barrel is the best choice.
mhb - Mike
B
Big Al
Guest
Truth be told, chrome lined bores vary in depth of plating. Uneven plating deposits is the rule of lining. One other thing to keep in mind that dimension for a bore that is intended for plating is that the ID is increases. This is easily verified by a call to any of the after market barrel makers who supply military style after market barrels.