Can someone define this and give me more information on it? I will be buying my ODCMP Garand and 1903a3 within the next week. They say that the garands are 3-5 on the throat errosion guages. "military servicable" Not totally sure what this means. I should be able to fire it right? Don't really want a wall hanger. By the same token WILL NOT be blasting the heck out if it. Help is always welcome gang. DAROGUE1
throat errosion in rifles??
- Thread starter darogue1
- Start date
Art Eatman
Staff in Memoriam
I believe the CMP website gives a pretty thorough explanation of throat-erosion numbers.
Basically, throat erosion can--but it doesn't always so happen--cause a loss of accuracy and thus cause larger sized groups. Doesn't mean the rifle can't be shot.
The obvious cure is to have new barrels installed...
, Art
Basically, throat erosion can--but it doesn't always so happen--cause a loss of accuracy and thus cause larger sized groups. Doesn't mean the rifle can't be shot.
The obvious cure is to have new barrels installed...
, ArtThe barrel throat is that portion right in front of the mouth of the case, where the bullet fits when the rifle is loaded. It gets a major blast of hot gas every time the rifle is fired and that affects the steel of the barrel. This is worst in rifles loaded (or overloaded) to gain high velocity, but it happens in all rifles.
As it becomes worse, throat erosion eats away at the lands in the barrel throat until the bullet gets a poor start on its way, tending to slew and skid as what is left of the rifling tries to grip it. While the bullet will eventually "straighen up and fly right" to some extent, its accuracy will not be the same as one with a good sendoff.
A brand new barrel would run 0-1 on a T-E gauge; a shot out barrel would be a 10 (in this case, the worst; we are talking about barrels, not women). A barrel gauging 3 would be in good shape; a 5 would still have a lot of life left and be perfectly serviceable.
Throat erosion should not be confused with rifling wear at the muzzle, caused mostly by cleaning rods. In a some rifles, muzzle wear can be corrected by back boring (drilling the bore to a larger size for 1/2 " or so), or cutting off the barrel to good rifling and recrowning. But that can't be done on an M1, since the M1 needs that barrel length to provide enough pressure through the gas port to function. The only practical way to correct muzzle wear on an M1 is a new barrel.
Jim
As it becomes worse, throat erosion eats away at the lands in the barrel throat until the bullet gets a poor start on its way, tending to slew and skid as what is left of the rifling tries to grip it. While the bullet will eventually "straighen up and fly right" to some extent, its accuracy will not be the same as one with a good sendoff.
A brand new barrel would run 0-1 on a T-E gauge; a shot out barrel would be a 10 (in this case, the worst; we are talking about barrels, not women). A barrel gauging 3 would be in good shape; a 5 would still have a lot of life left and be perfectly serviceable.
Throat erosion should not be confused with rifling wear at the muzzle, caused mostly by cleaning rods. In a some rifles, muzzle wear can be corrected by back boring (drilling the bore to a larger size for 1/2 " or so), or cutting off the barrel to good rifling and recrowning. But that can't be done on an M1, since the M1 needs that barrel length to provide enough pressure through the gas port to function. The only practical way to correct muzzle wear on an M1 is a new barrel.
Jim
kindlyoldcoach
New member
Are there some calibers more prone to throat errosion then others?
The classic throat-eroder in popular firearms lore is the .220 Swift. Tiny bullet, huge bottlenecked case, and a few cubic inches of slow-burning powder seem to be the recipe.
Conversely, a rifle chambered in something like .38 Special (fat bullet, straight case, slow enough to time in flight with a stopwatch) should keep a decent throat for quite a while.
'coach
The classic throat-eroder in popular firearms lore is the .220 Swift. Tiny bullet, huge bottlenecked case, and a few cubic inches of slow-burning powder seem to be the recipe.
Conversely, a rifle chambered in something like .38 Special (fat bullet, straight case, slow enough to time in flight with a stopwatch) should keep a decent throat for quite a while.
'coach
DAVID NANCARROW
New member
The simple answer is that the more pressure you make, the hotter it burns, and the quicker the barrel throat goes away. Barrel burners would be high capacity magnums as a general rule, especially in the smaller to medium bores.
The 223 is known for a pretty good barrel life, but if you firewall any cartridge, you can make the barrel wear faster due to heat and pressure, which are in lock step with each other.
Stainless barrels can help a bit, but know that nothing launching a barrel is flame proof.
The 223 is known for a pretty good barrel life, but if you firewall any cartridge, you can make the barrel wear faster due to heat and pressure, which are in lock step with each other.
Stainless barrels can help a bit, but know that nothing launching a barrel is flame proof.