CMP Forums

CMP Forums (http://forums.thecmp.org/index.php)
-   M1A/M14 (http://forums.thecmp.org/forumdisplay.php?f=100)
-   -   Using Chinese Barrel on Polytech With USGI Bolt (http://forums.thecmp.org/showthread.php?t=274667)

Danny 01-10-2021 10:02 AM

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.

nf1e 01-10-2021 10:25 AM

Simple shorten the iron that protrudes into the receiver to give the bolt room to function.

Danny 01-10-2021 11:33 AM

Quote:

Originally Posted by nf1e (Post 2002744)
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?

nf1e 01-10-2021 12:28 PM

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.

Nodakdad 01-14-2021 05:01 PM

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?

540 M-Sport 03-20-2021 07:44 PM

Quote:

Originally Posted by Nodakdad (Post 2004222)
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.

Danny 03-20-2021 07:47 PM

Quote:

Originally Posted by 540 M-Sport (Post 2027557)
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.

540 M-Sport 03-20-2021 07:58 PM

Quote:

Originally Posted by Danny (Post 2027559)
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.

Bart1015 04-19-2021 09:28 AM

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

jimthompson502002 04-20-2021 10:50 PM

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!!!


All times are GMT -5. The time now is 06:46 AM.