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  #1  
Old 01-10-2021, 10:02 AM
Danny Danny is offline
 
Join Date: Jun 2011
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Default Using Chinese Barrel on Polytech With USGI Bolt

I may consider building one of my Polytechs into a USGI Type Rifle. I know nothing about issue M14 type clones. I know some have used the Chinese Barrel, but as far as I know, the breech end of the barrel will hit a USGI Bolt when installed. What is done to get this to work? I know what to do to fit a USGI Bolt to a Chinese Receiver. I have not had to do it yet because my one Polytech build took a USGI Bolt without modification. My other two won't.
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  #2  
Old 01-10-2021, 10:25 AM
nf1e nf1e is online now
 
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Simple shorten the iron that protrudes into the receiver to give the bolt room to function.
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  #3  
Old 01-10-2021, 11:33 AM
Danny Danny is offline
 
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Quote:
Originally Posted by nf1e View Post
Simple shorten the iron that protrudes into the receiver to give the bolt room to function.
Just the hood part? Typically, by how much are they too long? Thousandths of an inch, or a greater amount?
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Looking for Rifles:
Springfield Armory 5,940,259, 5,840,184, 4,238,435 and 2,023,912.
Harrington & Richardson 5,549,399.

"Furniture" is NOT stocks and handguards.

I want to punch Dr. Rick from Progressive in the mouth, just because.

"REPO" M1 Parts: The parts you buy that they come to take back later on.
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  #4  
Old 01-10-2021, 12:28 PM
nf1e nf1e is online now
 
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10 to 20 ths as I remember. Been at least 10 years since I ground one down. Must have worked because I still have two rifles with them in service rifle builds and they do a great job. Much better than most usgi chrome lined barrels, that I have used over the years.
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  #5  
Old 01-14-2021, 05:01 PM
Nodakdad Nodakdad is offline
 
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I've read about having to modify them to get the US bolt to work, but I can't picture it. Anyone got a picture of it?
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  #6  
Old 03-20-2021, 07:44 PM
540 M-Sport 540 M-Sport is offline
 
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Quote:
Originally Posted by Nodakdad View Post
I've read about having to modify them to get the US bolt to work, but I can't picture it. Anyone got a picture of it?
Go to the M14/M1A forum on Facebook. Ron Smith from SEI has several videos on Polytech M14s and shows the various modifications he does on them to make them better shooters. One is the recut the bolt races to accept a USGI bolt.
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  #7  
Old 03-20-2021, 07:47 PM
Danny Danny is offline
 
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Quote:
Originally Posted by 540 M-Sport View Post
Go to the M14/M1A forum on Facebook. Ron Smith from SEI has several videos on Polytech M14s and shows the various modifications he does on them to make them better shooters. One is the recut the bolt races to accept a USGI bolt.
No Facebookie for me. There was some controversy concerning Smith Enterprises some years ago in this or another forum.
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-------------------------------------------------------------------------------------------------------
Looking for Rifles:
Springfield Armory 5,940,259, 5,840,184, 4,238,435 and 2,023,912.
Harrington & Richardson 5,549,399.

"Furniture" is NOT stocks and handguards.

I want to punch Dr. Rick from Progressive in the mouth, just because.

"REPO" M1 Parts: The parts you buy that they come to take back later on.

Last edited by Danny; 03-20-2021 at 07:56 PM.
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  #8  
Old 03-20-2021, 07:58 PM
540 M-Sport 540 M-Sport is offline
 
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Quote:
Originally Posted by Danny View Post
No Facebookie for me. There was some controversy concerning Smith Enterprises some years ago in this or another forum.
Too bad, I don't know Ron personally, but he is super helpful on that page, offering advice and wonderful videos of mods and improvements to the M1A platform.
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  #9  
Old 04-19-2021, 09:28 AM
Bart1015 Bart1015 is offline
 
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don't have much to contribute, but FWIW, I have a Federal Ordnance receiver with a Chinese barrel that I bought 10+ years ago. It is way more accurate than I am. I have had no issues at all with it and it outshoots my SA Scout.

The gun has a GI bolt installed. The guy who built the gun said he had to remove a small amount of metal from the barrel to clear the bolt.


Brett
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  #10  
Old 04-20-2021, 10:50 PM
jimthompson502002 jimthompson502002 is offline
 
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Location: La Crosse, Wisconsin
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There were two manufacturers and several generations of Chinese M14 ( they are NOT M1A's--that's an SAI product, exclusively and ONLY!!) and their barrels.

However, the barrels were all very good in terms of roundness, straightness, dimensional conformance, concentricity, and so on. A few early ones featured the very loose "NATO" chambering similar to that found on HK21 GPMG's, however, and while accurate, they were TROUBLE in terms of brass life and getting them to civvy headspace specs.

There's a middle area, before rifled firearms from China were effectively banned due to very heavily financed lobbying pressure and bribery, from stateside manufacturers, where it seemed for a while every one I measured and tested had significant differences from the last...very few of which impacted performance downrange.

I always thought the first of them were designed for Chinese-made, steel-cased, "throw away the hulls" ammo. Almost tore my arm out of the socket trying to resize some G.I. brass fired through an early NORINCO, then took the brass to a gun show to dump it. Not worth pulled muscles!!!

Last edited by jimthompson502002; 04-21-2021 at 07:27 PM.
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