Steelharp
Member
I know there's probably places I can find this, but I trust you guys more than anybody. What do things like "Throat Erosion is 4. Muzzle Wear is 2.5" mean? What are good/bad numbers?
Help my Garand ignorance...
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jrfoxx
Member
If you are quoting from CMP, i believe I was told that the numbers are on a scale from 1-10. Dont really know if that would hold true anywhere else, but it would seem like a common standard. Someone else may have more or better info on this though.
ReadyontheRight
Member
Others probably know better than I, but I will take a shot.
Muzzle wear refers to how large the barrel opening is at the muzzle. As the barrel is "shot out", it gets bigger. This is tested with a muzzle gauge specifically for 30-caliber. Low numbers are good. You can check muzzle wear yourself with a 30-cal bullet - if it goes in just a little, the muzzle is nice and tight. If it falls in, the muzzle is shot out and will likely be inaccurate.
Throat erosion is similar, from the receiver - end.
Both are also a proxy for overall rifle wear.
From the www.odcmp.com website:
-Check muzzle for excessive wear. If muzzle gauge reads '3' or less and no excessive wear of the crown is present, barrel passes service grade criteria. If muzzle gauge reading is over 3 or wear of crown is evident, barrel passes for rack grade.
-Gauge Throat Erosion (TE). If TE is 5 or under, classify rifle as Service grade. If reading is between 5-8, rifle passes Rack grade criteria. If reading is over 8, reject rifle and place in reject container.
Muzzle wear refers to how large the barrel opening is at the muzzle. As the barrel is "shot out", it gets bigger. This is tested with a muzzle gauge specifically for 30-caliber. Low numbers are good. You can check muzzle wear yourself with a 30-cal bullet - if it goes in just a little, the muzzle is nice and tight. If it falls in, the muzzle is shot out and will likely be inaccurate.
Throat erosion is similar, from the receiver - end.
Both are also a proxy for overall rifle wear.
From the www.odcmp.com website:
-Check muzzle for excessive wear. If muzzle gauge reads '3' or less and no excessive wear of the crown is present, barrel passes service grade criteria. If muzzle gauge reading is over 3 or wear of crown is evident, barrel passes for rack grade.
-Gauge Throat Erosion (TE). If TE is 5 or under, classify rifle as Service grade. If reading is between 5-8, rifle passes Rack grade criteria. If reading is over 8, reject rifle and place in reject container.
VG
Member
And FWIW, I'd say the MAJORITY of rifles for sale at gun shows have barrels worn beyond these standards.
cracked butt
Member
Sounds like a typical barrel that has a little bit of use at best.
From what I've seen, a new GI barrel will have a throat erosion ration of around 2-3 and a muzzle wear rating of 1-2.
There are lower numbers on the scale, but out of a sampling of many new barrels, some will have slightly lower or slightly higher numbers due to manufacturing tolerances.
Throat erosion is just the throat wearing out due to hot gasses being blasted through it with every shot. Muzzle wear is the loss of metal on the lands due to cleaning practices.
A new G.I. barrel should have a TE of "0" when installed. You will see some brand new, just installed, barrels with a TE of "1" due to timing issues when they were installed. Nothing wrong with that. A new barrel shouldn't be above "1," or maybe "2" (at the absolute high end). Generally, the lower the better, with anything under "5" being preferable. The highest on any of my rifles is "3."
Btw, a rifle with a good TE can still be a poor shooter if the muzzle wear is excessive. A rifle with a very good muzzle will sometimes shoot well even with a high TE. Low on both is the way to bet, though.
Btw, a rifle with a good TE can still be a poor shooter if the muzzle wear is excessive. A rifle with a very good muzzle will sometimes shoot well even with a high TE. Low on both is the way to bet, though.
jacobtowne
Member
As I understand it, the muzzle gauge measures bore (land) diameter in thousandths of an inch. At 0, the diameter is .300, or .30. At 3, which is the bore diameter of the M1903A1 I bought from the CMP, it is .303.
Still shoots just fine, though.
JT
Still shoots just fine, though.
JT
45Badger
Member
Mikey- Ya getting a Garand? It's hard to stop at just one!
Steelharp
Member
No, I'm not getting a Garand... not right now, anyway. Someday, maybe... I don't know. The funds and the stars have to line up, ya know? 
On a personal note, I can't even do a refund right now... so don't ask!!!
On a personal note, I can't even do a refund right now... so don't ask!!!
Crosshair
Member
I bought a Garand from Scheels that turned out to have a shot out barrel. Since they guarantee the condition of the guns and the bore was rated as "excellent" I get a new barrel put onto it for free. New barrel is really nice.
New barrel is really nice.- Status