M14 Forum


Questions about Polytech M14

This is a discussion on Questions about Polytech M14 within the The M14 forums, part of the M14 M1A Forum category; I recently purchased a Polytech M14S knowing I would change some parts on it. My first improvement is to change the gas cylinder, piston, lock, ...


Go Back   M14 Forum > M14 M1A Forum > The M14

Reply
 
LinkBack Moderator Tools Display Modes

Old June 18th, 2011, 08:11 PM   #1
Old Salt
 
GardenValley's Avatar
 
Join Date: Jun 2011
Location: Texas
Posts: 1,079
Questions about Polytech M14

I recently purchased a Polytech M14S knowing I would change some parts on it. My first improvement is to change the gas cylinder, piston, lock, and plug. Several persons had told me that all parts except the bolt can readily be replaced with U.S. GI parts, but I now wonder if that is the case. The gas cylinder is new GI and when I installed it, it slipped right in place and fit better that the Chinese gas cylinder. But when I started to install the GI gas cylinder lock I discovered it would not screw on. The threads on the barrel apparently are different from GI threads. I have a new GI gas cylinder plug and to further investigate I tried the Chinese gas cylinder plug in the GI cylinder and discovered it too would not screw in, the threads also apparently being different. I don't have a GI flash suppressor nut, but I am now wondering if it also is threaded differently. Has anyone else experienced this same issue?

GardenValley is online now  
Remove Ads
Old June 18th, 2011, 09:00 PM   #2
Designated Marksman
 
Oryguner's Avatar
 
Join Date: Nov 2003
Location: Oregon
Posts: 665
My understanding is that with the exception of the receiver thread, the gas cylinder lock and the flash suppressor castle nut threads are metric on barrels of Chinese origin. You have to wonder.....when they elected to copy the M14 receiver so close to original specs.....why they chose to change the thread pitch on the barrel. But....only on two of the three threaded areas. Go figure?

Oryguner is offline  
Old June 18th, 2011, 09:20 PM   #3
Automatic Rifleman
 
Join Date: Feb 2008
Location: Texas
Posts: 141
I have a VERY early Polytech. Think low 700 serial number.
All the threads on the rifle are metric except the scope mount hole on the side of the receiver. I have not checked the barrel but I think that is the only other exception to the rule. Even the rear sight is metric.

It's odd considering everything else on the gun is a match to GI stuff. I guess the tooling was easier to build in metric.

feets is offline  
Old June 18th, 2011, 10:20 PM   #4
Old Salt
 
GardenValley's Avatar
 
Join Date: Jun 2011
Location: Texas
Posts: 1,079
Another difference ...

Staying up late and just noticed another oddity. A GI SA op rod will not fit on this Polytech. There is more relief on the Polytech op rod just above the top of the tab. It appears the SA op rod would have to be relieved just a little in this area to fit on the Polytech.

GardenValley is online now  
Old June 19th, 2011, 03:50 AM   #5
Dodgin' The Reaper
 
Different's Avatar
 
Join Date: Jul 2003
Location: Las Vegas, NV, USA
Posts: 8,960

Awards Showcase

The gas cylinder plug and gas cylinder threads are also metric. There's nothing wrong with the Chinese gas system. I would leave it on the rifle.

Different is offline  
Old June 19th, 2011, 03:57 AM   #6
Dodgin' The Reaper
 
Different's Avatar
 
Join Date: Jul 2003
Location: Las Vegas, NV, USA
Posts: 8,960

Awards Showcase

Quote:
Originally Posted by feets View Post
I have a VERY early Polytech. Think low 700 serial number.
All the threads on the rifle are metric except the scope mount hole on the side of the receiver. I have not checked the barrel but I think that is the only other exception to the rule. Even the rear sight is metric.

It's odd considering everything else on the gun is a match to GI stuff. I guess the tooling was easier to build in metric.
The parts on your rifle were made in the early 1960s as part of the project at State Arsenal 356 to build 100,000 M14 rifles for armed insurrection in another country. The parts were not originally intended for compatibility with U. S. made M14 rifles. It was likely a matter of practicality for State Arsenal 356 to use existing dies for cutting the threads on the gas system parts. 100,000 rifles in those days was not one of the larger small arms projects. The receiver on your rifle was manufactured in the late 1980s as part of a rifle intended for export sales to the United States.

Different is offline  
Old June 19th, 2011, 05:34 AM   #7
Newbie
 
Join Date: Jun 2011
Location: Lake Ariel, PA
Posts: 9
Sarco has the ChiCom specific gas regulator parts if you need them, BTW.

quikdraw67 is offline  
Old June 19th, 2011, 06:29 AM   #8
Old Salt
 
brycom1's Avatar
 
Join Date: Feb 2007
Location: CO
Posts: 1,436
You can use the new gas cylinder parts but you have to use the chinese cylinder lock.

The chinese oprod track on the reciever is tighter than a U.S. reciever so you will have to fit the oprod to the reciever.

brycom1 is offline  
Reply

  M14 Forum > M14 M1A Forum > The M14



Search tags for this page
poly tech m14
,
polytech m 14 reviews
,
polytech m-14
,
polytech m-14 reviews
,

polytech m14

,
polytech m14 parts
,
polytech m14 parts compatibility
,

polytech m14 review

,
polytech m14s review
,
polytech m1a review
,
polytech m1a reviews
,
polytechm14
Click on a term to search for related topics.

Moderator Tools
Display Modes


Similar M14 Forum Discussions
Thread Thread Starter Forum Replies Last Post
Who makes M14 type rifles? And, other questions. sandanbob Modern M14 13 May 11th, 2010 06:28 AM
Polytech M14 and JAE Gen1 Stock ***Rifle SPF - Stock Still Available - $ Lowered*** jimonfly PX 1 September 24th, 2009 08:53 AM
fact or fiction? stichy The M14 16 February 27th, 2008 07:45 AM
My Polytech M14 experience so far JKJ The M14 9 September 26th, 2006 11:24 AM
WTK: Norinco M14 or PolyTech M14? Kim The M14 15 July 9th, 2006 01:02 PM



Top Gun Sites Top Sites List