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  #1  
Old 01-08-2019, 03:12 PM
Bruw Bruw is offline
 
Join Date: Dec 2018
Location: Colorado
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Default Throat erosion on new barrel?

Just received my third CMP rifle, a CMP Special IHC 30-06. Chose this one specifically to shoot JC Garand matches at a rifle club nearby. Rifle is beautiful and I couldn't be happier with it. The one question I have is why the hang tag says the throat erosion measured 1 when it should be a brand new barrel? Not really concerned about it, just curious. I assumed erosion is 0 on new barrels. My .308 CMP Special was 0/0. Thanks in advance for the knowledge.
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  #2  
Old 01-08-2019, 04:10 PM
Orlando Orlando is offline
 
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I have never seen a new barrel with a TW measurement of 0 .Your barrel is fine
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  #3  
Old 01-08-2019, 05:08 PM
jeeperbob jeeperbob is offline
 
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Default Throat erosion

A new barrel is finished reamed in the chamber which takes out an amount of material depending on how much reaming is required for headspacing, etc.
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  #4  
Old 01-09-2019, 01:52 AM
Doubs43 Doubs43 is online now
 
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Location: Byron, GA
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Quote:
Originally Posted by Orlando View Post
I have never seen a new barrel with a TW measurement of 0 .Your barrel is fine
The CMP Special in .308 that I bought in 2013 measured 0/0 according to the tag.

I started a thread several weeks back asking if new barrels ever measured anything but 0/0 and many responses said that they often did.
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  #5  
Old 01-09-2019, 03:17 PM
Herrmann Herrmann is offline
 
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Location: Terre Haute, IN
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Not sure about .308, but years ago I bought several correct and collector M1s from the CMP. SA and HRA. Essentially new guns and typically had a T.E. of 3. Reaming?
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  #6  
Old 01-09-2019, 05:24 PM
Mike in NC Mike in NC is offline
 
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A TE of 2 to 2.5 is very common on new post-war USGI 30.06 Garand barrels. The only USGI 30.06 Garand barrels that I have fairly consistently seen have TE of less than that are LMR barrels.
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  #7  
Old 01-09-2019, 05:34 PM
Bruw Bruw is offline
 
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Thanks for all the info. This place is great for the newly addicted M1 lovers.
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  #8  
Old 01-09-2019, 07:11 PM
Herrmann Herrmann is offline
 
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I am not a big fan of headspace gaging, but a zero might suggest a problem with an unreamed barrel. However, if the bolt closes properly on a round it would seem you are OK.
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  #9  
Old 01-10-2019, 09:56 AM
ljagdtiger ljagdtiger is offline
 
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Default Throat erosion

Not usual for new barrel to read one. When you get much higher readings it is time for concern. Be happy with the CMP Garand and shoot well and enjoy.

ljagdtiger
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  #10  
Old 01-10-2019, 10:44 AM
jcj54 jcj54 is offline
 
Join Date: Jul 2013
Posts: 46
Default New barrel throat

My USGI throat gauge has a dimple at about 1.75. When I asked a USMC Armorer who kew M1 and M14 rifles extensively, he told me that was where the throat had to be to chamber M1 or M2 ball.
He said a throat of 0 would have no place for the bullet.

Last edited by jcj54; 01-10-2019 at 10:55 AM.
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