The Firing Line Forums

Go Back   The Firing Line Forums > The Hide > The Art of the Rifle: General

Reply
 
Thread Tools
Old January 28, 2009, 09:30 PM   #1
Lamb
Junior Member
 
Join Date: January 28, 2009
Location: Montgomery, Alabama
Posts: 7
Polytech M14

Can anyone tell me about the Polytech M14 IDE .308 stamped on the side. It does not read 7.62x51 like the ones I have seen. Also the wood is smooth and glossy and also light in color.
Lamb is offline  
Old January 28, 2009, 10:03 PM   #2
farmer-dave
Senior Member
 
Join Date: May 4, 2006
Location: Solomon, Kansas
Posts: 127
It's a good rifle, but its been reported that the bolt is a little soft, many people send theirs to a guy by the name of warbird that will switch out to a gi bolt. The receiver is gi spec and the barrel chrome lined. They originally sold for around 4-500 dollars. They can easily go for 8-900 now. Many people shoot thousands of rounds before the bolt gets out of headspace, it's recommended to buy a nato go, no-go gauge. I'm sure some real experts will jump in.
farmer-dave is offline  
Old January 28, 2009, 10:10 PM   #3
Lamb
Junior Member
 
Join Date: January 28, 2009
Location: Montgomery, Alabama
Posts: 7
So even though it says .308 use a 7.62x51 Nato guage. I've heard there is a little difference between the two gauges.

Last edited by Lamb; January 28, 2009 at 10:30 PM. Reason: one more question
Lamb is offline  
Old January 28, 2009, 10:28 PM   #4
farmer-dave
Senior Member
 
Join Date: May 4, 2006
Location: Solomon, Kansas
Posts: 127
Yeah consider it a typo by the chinese, it's definitely recommended to shoot Nato 7.62x51. I have in the past shot some 308 150 grain ammo in mine but definitely stay away from anything 180 grain.
farmer-dave is offline  
Old January 28, 2009, 10:36 PM   #5
Lamb
Junior Member
 
Join Date: January 28, 2009
Location: Montgomery, Alabama
Posts: 7
Well thanks for the help. I paid $800.00 in almost new condition. It even had the old style all steel bipod and nice leather sling w/two 20 round mags
Lamb is offline  
Old January 29, 2009, 11:12 AM   #6
Citizen Carrier
Senior Member
 
Join Date: July 10, 2008
Location: Columbus, OH
Posts: 671
You did well. Paid about that much for my Polytech about 10 years ago. Used it as the basis for a match rifle, but I was too cheap at the time to put a proper barrel on it. Thus I was never able to realize outstanding accuracy from it.

It is having a Krieger barrel put on it right now.

I had the bolt conversion to an H&R bolt by Smith Enterprises. I can't hurt, but I suspect the whole thing about "soft" chinese bolts comes from a different cause altogether.

A guy named Zeideker writes a lot of reloding books and one article, available online titled "Reloading for the Match M14", talks about how all M14 type rifles will lose some headspace tolerance while shooting.

The culprit is loss of parkerization finish on the locking lug bearing surfaces, both on the lugs and their recesses in the receiver. The best way to protect from this is to keep those areas swimming in grease.
__________________
Once you've got your sights adjusted to the ammunition you have, step away from the bench. In competition or the field...there are no benches.
Citizen Carrier is offline  
Old January 29, 2009, 01:37 PM   #7
farmer-dave
Senior Member
 
Join Date: May 4, 2006
Location: Solomon, Kansas
Posts: 127
Previous owner must have added the bipod and the sling, check to see if you still have the cleaning kit in the butstock.
farmer-dave is offline  
Old January 29, 2009, 01:52 PM   #8
Lamb
Junior Member
 
Join Date: January 28, 2009
Location: Montgomery, Alabama
Posts: 7
I would like to get a Chinese upgrade. Who would be the best Fulton or Smith? Also what is the price? I appreciate you guys helping me out!
Lamb is offline  
Old January 29, 2009, 06:09 PM   #9
farmer-dave
Senior Member
 
Join Date: May 4, 2006
Location: Solomon, Kansas
Posts: 127
Warbirdscustomguns.com

A lot of other places will tell you, you need a new barrel, or a bunch of other stuff. This guy has a excellent reputation on some of the m14 boards that I used to hang out. I'm sure the other places are good too but they might push you to do more then needed. I personally wouldn't do a thing unless you headspace is bad. Some people do buy the norinco's and polytechs just for the forged receiver and then do a custom build. It all depends on how much money you want to dump. I'm pretty frugal.
farmer-dave is offline  
Old January 29, 2009, 06:19 PM   #10
nwuboy
Member
 
Join Date: January 27, 2009
Posts: 15
How do the polytechs compare to a springfield? I'm trying to decide between the two.

also, have you guys seen the Troy MCS stock for the M14/M1A ? It looks so awesome. Pity it's now impossible to find.
nwuboy is offline  
Old January 29, 2009, 06:31 PM   #11
Citizen Carrier
Senior Member
 
Join Date: July 10, 2008
Location: Columbus, OH
Posts: 671
The best part about the Chinese guns are the milled, forged receivers. Those are just plain better than castings, which SA uses. The op rods are probably just as good, or if forged, better than the cast rods SA guns sometimes have.

Everything else though, barrel, trigger group, rear sight, stock, stock metal, etc. are better on the SA gun.

At least that's what I gather, seeing as how I own a Polytech but have only inspected SA guns.
__________________
Once you've got your sights adjusted to the ammunition you have, step away from the bench. In competition or the field...there are no benches.
Citizen Carrier is offline  
Old January 29, 2009, 07:11 PM   #12
texfar
Senior Member
 
Join Date: November 27, 2004
Location: TEXAS
Posts: 404
My last build was done by Tim at Warbirds and I could not be happier. When you get the bolt conversion done, mine was TRW, he will headspace it to shoot either the .308 commercial or the 7.62 x 51. You got a great buy on that Poly!!



I added a USGI suppressor, USGI rear sight unit, Sadlak op rod spring guide, Fulton op rod spring, NM trigger group, USGI and a complete repark. Stock is one from Fred's, birch tiger stripe. I built it from parts left over from Fulton PEERLESS NM build. Bought a Chinese barreled action in new condition and went from there. Trust me, you got a good deal. Takes about 1200 to put one together.
Ken

Last edited by texfar; January 29, 2009 at 07:18 PM. Reason: info
texfar is offline  
Old January 30, 2009, 10:07 AM   #13
Lamb
Junior Member
 
Join Date: January 28, 2009
Location: Montgomery, Alabama
Posts: 7
Texfar,

That stock is sweet!!!. I went to warbirds web site and I like the fact that he shows his work to the public. Nice!. Do you know if when you call, are you able to speak with him. Have tried other places (I wont mention the ones) and get a person who doesn't know to much.
Lamb is offline  
Old January 30, 2009, 10:59 AM   #14
Huey Long
Senior Member
 
Join Date: December 22, 2008
Posts: 239
The Chicom receivers are among the best on the market, due to the fact that they're forged and not cast, but the rest of the rifle leaves a great deal to be desired. If I were you, I'd save my pennies and send it in to Fulton Armory to have it completely rebuilt. Then you'll have an M-14 that will be the envy of every gunny in your town.

Years ago, I saw a Chicom M-14 for sale for $600 and I still kick myself for not buying it.

Last edited by Huey Long; February 1, 2009 at 05:33 AM.
Huey Long is offline  
Old January 30, 2009, 12:09 PM   #15
Citizen Carrier
Senior Member
 
Join Date: July 10, 2008
Location: Columbus, OH
Posts: 671
As I understand it, the modification for Chinese guns to take a USGI bolt comes in basically two types.

One, the Chinese receiver is machined/modified to take a USGI bolt.

Two, the USGI bolt is modified to fit in the Chinese receiver.

I could be wrong, but it is my understanding that Smith Enterprises and Warbirds modifies them the first way and Fulton Armory modifies the second way.
__________________
Once you've got your sights adjusted to the ammunition you have, step away from the bench. In competition or the field...there are no benches.
Citizen Carrier is offline  
Old January 30, 2009, 03:56 PM   #16
Lamb
Junior Member
 
Join Date: January 28, 2009
Location: Montgomery, Alabama
Posts: 7
O.K. next question. Since my polytech says .308 and not anywhere does it say 7.62x51 WHAT AMMO SHOULD I USE? 7.62x51 or .308? And if you have a polytech stamped .308 what make do you use.
Lamb is offline  
Old January 30, 2009, 04:42 PM   #17
Citizen Carrier
Senior Member
 
Join Date: July 10, 2008
Location: Columbus, OH
Posts: 671
Use only ammunition marked 7.62 NATO. It doesn't matter what the Chinese stamped on it. The guy stamping it and the guy who told him to stamp it that way probably don't know the difference between the two cartridges and likely don't care.

This isn't so bad a thing, as the affordable bulk ammunition you can buy for it is 7.62 NATO rather than commercial .308 Winchester.

.308 is much, much higher pressure ammo than 7.62.

Anywhere from 10,000 to even 20,000 pounds per square inch hotter.

Oh, your rifle will chamber and fire .308, but you are increasing parts wear and stresses on your rifle by using it.

And like I said....308 Winchester is generally more expensive than surplus military 7.62 NATO ammo anyway.

Up until now, I've used surplus South African PMP 7.62 NATO ammo for it, but I haven't bought any of that in a long time and only have one battle pack sleeve of it left.

But any surplus military ammo from basically any country should work. I used South African because it was available and had good references when it came to accuracy. Now I have acquired about 1700 rounds or so of Remington 7.62 International Match BTHP 168 grain stuff. Older ammo, still in the factory boxes. It is going to be my match ammo for the few matches I shoot a year in which I will use the M14.

After my rifle is re-barreled with the Krieger heavy barrel, I will see how the ammo does.
__________________
Once you've got your sights adjusted to the ammunition you have, step away from the bench. In competition or the field...there are no benches.
Citizen Carrier is offline  
Old January 30, 2009, 04:53 PM   #18
Lamb
Junior Member
 
Join Date: January 28, 2009
Location: Montgomery, Alabama
Posts: 7
Thanks Citizen C. I forgot you told me that a couple days ago. I will make sure it's 7.62x51.
Lamb is offline  
Old January 30, 2009, 05:42 PM   #19
Huey Long
Senior Member
 
Join Date: December 22, 2008
Posts: 239
.308 is much, much higher pressure ammo than 7.62.

Not true:

http://www.falfiles.com/forums/showt...threadid=22889
Huey Long is offline  
Old January 30, 2009, 06:30 PM   #20
Citizen Carrier
Senior Member
 
Join Date: July 10, 2008
Location: Columbus, OH
Posts: 671
I can't access that link, but here's a few that substantiate what I believe.

http://www.surplusrifle.com/shooting...nato/index.asp

"In terms of pressure, there is a wide (very wide) gap between the 7.62 NATO and the .308 Winchester. Here at Surplusrifle.com, we recommend in the strongest possible terms that you do not fire factory .308 Winchester ammunition in any Mil-Surp rifle chambered for the 7.62 NATO round."

Keeping mind that even though the Polytech may be stamped ".308", the M14 design was built for the 7.62 NATO. This wouldn't be such a problem if the M14 had an adjustable gas system like the FAL.

http://www.thefirearmblog.com/blog/2...s-762x51-nato/

"You CAN encounter problems going the other way, however. A commercial .308 Win round can exceed the max rated pressure for the 7.62×51. So, you should avoid putting full-power .308 Win rounds into military surplus rifles that have been designed for 50,000 psi max."
__________________
Once you've got your sights adjusted to the ammunition you have, step away from the bench. In competition or the field...there are no benches.
Citizen Carrier is offline  
Old January 30, 2009, 10:45 PM   #21
texfar
Senior Member
 
Join Date: November 27, 2004
Location: TEXAS
Posts: 404
The first thing that you need to do if you are not doing a bolt conversion is have the head space checked accurately. That will tell you if you can safely fire both 7.62 and commercial .308, or neither. I shoot both through rounds through both of my M14's because they are head spaced to do so. One by Fulton and the other, Tim at Warbirds. The only thing you MUST NOT do with commercial ammo is to shoot light magnum or magnum loads. I shoot standard Remington 150 gr Corlok rounds all day. I also shoot 168 Federal Premium and Black Hills ammo. There is no problem. Go here to learn more about the M14 platform than you thought possible. http://m14tfl.com/upload/ Hope this helps.
Ken
texfar is offline  
Old January 31, 2009, 12:42 AM   #22
Jason_G
Senior Member
 
Join Date: December 18, 2006
Location: Louisiana
Posts: 1,902
Quote:
How do the polytechs compare to a springfield?
The Polys are forged, vs. the SAI cast receivers. There's really no significant difference in the quality of the steel. Some will argue that forged is better, but a properly heat treated cast receiver will outlive you. The major difference is the outside dimensions as they apply to scope mounting. The SAIs are known to be slightly out of spec (as per USGI blueprints), and can interfere with proper mounting of some popular scope mounts. It can be overcome, but sometimes at the cost of more time, and sometimes more money. In this regard, the Poly is superior. If you are planning on an iron sights gun, then there is not a significant difference either way.

The SAI bolts are forged, and generally of excellent quality save a recall in the '80's. The Polys are sometimes softer than spec, which can eventually lead to headspacing issues.

Both rifles will have excellent op rods.

The gas system on the SAI is closer to spec than on the Polys IIRC.

I'm sure I am leaving stuff out, but I can't remember everything right now...


Jason
__________________
"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed." -Amendment II, Constitution of the United States of America
Jason_G is offline  
Old January 31, 2009, 03:23 AM   #23
Huey Long
Senior Member
 
Join Date: December 22, 2008
Posts: 239
Quote:
I can't access that link
What it basically boils down to is that is that you get a different pressure number for .308 Winchester depending on which gauge you choose to measure it with. You get 52,000 PSI with the copper crusher gauge, which is known as copper units of pressure (cup) and you get 62,000 PSI for the same loading of the same .308 Win with the piezoelectric transducer gauge. The use of these two different gauges by the US military (copper crusher) and the commercial SAAMI specs (piezo) is responsible for the fictitious net rumor that .308 is loaded to much higher pressures (62,000) than 7.62 NATO (50,000). They are actually loaded to approximately the same pressures when you measure with the same gauge (50,000 vs 52,000 PSI).

You can tell that the chamber pressure is similar just by comparing the energy of the two rounds. The 7.62 NATO round has 2,472 ft·lb of energy and the 150 gr .308 Winchester round has 2,648 ft·lb of energy. Since chamber pressure is basically a function of energy, the chamber pressures must be very similar.

In short, the .308 Winchester is a little hotter than the 7.62 NATO, but not enough to make it unsafe when fired from a 7.62 NATO rifle.
Huey Long is offline  
Old January 4, 2011, 05:30 AM   #24
bluebeast
Junior Member
 
Join Date: January 3, 2011
Posts: 1
New to the M14

Greetings fellow Polytech M14 people,
New to the world of the polytech M14. Picked up a used polytech M14S chambered in 308. Have fired about 150 rounds through it with no issues.
I was able to pick up, online, 500 rounds of Wolf, 150gr, ammo, thought I was getting a good deal on plinking ammo. Anyhow was at the range yesterday and one of the range guys saw that I was firing this type of ammo and advised me that sooner or later I am going to have to replace the barrel and bolt parts such as the extractor. Was not sure on this but his explaination on this was that the metal to metal contact from the bullet casing can cause issues that will expand the chamber of the barrel because I do not have a chomed? barrel.
Did some research and found out that if the weapon system is original, should be chrome lined. How do you know or not if you have the chrome lined barrel. Also what know issues are there with the poly tech M14.
Thanks,
Birk
bluebeast is offline  
Old January 4, 2011, 08:20 AM   #25
SR420
Senior Member
 
Join Date: May 12, 2005
Location: Georgia, USA
Posts: 2,806
Poly Tech and Norinco M14s came with chrome lined barrels and they are chambered/head spaced for 7.62 NATO.
Shoot surplus ammo until you invest in a USGI bolt conversion - use Warbird or Smith Enterprise, Inc. (SEI) for this service.
Both of these smiths can do this without replacing your chrome lined barrel.

Is the receiver on your rifle side stamped or heel stamped?





.
__________________
facebook.com/M14EBR.US

Last edited by SR420; January 4, 2011 at 10:01 AM.
SR420 is offline  
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 03:13 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
This site and contents, including all posts, Copyright © 1998-2014 S.W.A.T. Magazine
Copyright Complaints: Please direct DMCA Takedown Notices to the registered agent: thefiringline.com
Contact Us
Page generated in 0.11600 seconds with 7 queries