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falbuff
March 14, 2009, 14:02
I need some advice on a bolt exchange on a polytech M14 I picked up.I have a new TRW complete bolt to exchange is there somebody in the socal area that does this kind of work.
I've built some fals and a couple Romy's but the M14 is all Greek to me.

Survey Punk
March 14, 2009, 14:54
All you need is a go and no-go headspace gauge. Bolt needs to be stripped. Just close on go and definately not close on no-go.
Fulton armory may provide this service.

JB

kalliste
March 14, 2009, 15:07
Do a search - there have been a couple of threads with a lot of discussion of this. It requires modification of the rifle to fit a GI bolt to Polytech.Polytech & Norinco owners must read this about USGI bolt conversion This information will educate you about how to avoid so-called gunsmiths & armorers who claim they know how to do the USGI bolt conversion to your Polytech or Norinco. If others charge a fee for a tech inspection, that's your first clue that you should find someone else to do the work. They should already know what needs to be done, not trying to educate themselves by working on a customers rifle. I never charge a fee for a tech inspection, ever. I don't need to because I know what needs to be done to install a USGI bolt properly. Also, the Chinese barrel "can be used" when I do the USGI bolt conversion. "You don't need a new commercial barrel" as most so-called gunsmiths claim. Bottom line is they just want your money. Please remember that Chinese rifles converted to use a USGI bolt by these inexperienced people will not be accepted by me, to do work on. The USGI bolt conversion is not being done correctly by some of the others because they don't have the experience to do it right. I will only accept Chinese rifles with a USGI bolt conversion already done, if Smith Ent. or myself did the work. It's my intention to help customers avoid very costly mistakes. I have done 1000's of these bolt conversions and not 1 customer has ever had a problem. My reputation far exceeds me and customer satisfaction is always guaranteed. I have been doing the USGI bolt conversion on Chinese receivers for over 22 years. The other so-called gunsmiths are just starting and have no experience at all. You be the judge. I believe you will make the right choice and rely on a true expert with years of experience.
http://www.warbirdscustomguns.com/Rifle%20Shop%20services.htm (http://tinyurl.com/cwhpc8)

falbuff
March 14, 2009, 15:30
your right I'll get a email out today.
Thanks Greg

TerryN
March 14, 2009, 21:02
You might give Jon Tank a shout at 402.727.1317, www.tanksrifleshop.com

Jon does outstanding work and his prices are reasonable. I've known him since 1981, and he's one of the few people that I'll let work on my own guns.

ActionYobbo
March 15, 2009, 08:10
not all the poly bolt were bad. it was just a small batch. do a search and find out if yours is in the bad batch. I have one thats not in the bad batch and have fired about 7000 rounds and it has no problem at all

Otis Treekiller
March 15, 2009, 08:35
Originally posted by ActionYobbo
not all the poly bolt were bad. it was just a small batch. do a search and find out if yours is in the bad batch. I have one thats not in the bad batch and have fired about 7000 rounds and it has no problem at all

+1. Most Poly bolts will never need to be replaced.

falbuff
March 15, 2009, 09:09
The problem with this rifle is the bolt is loose enough that the roller jumps out of the op rod when fired
but not every round.

falbuff
March 15, 2009, 09:34
do you have a link to check for the bolt hardness.

ActionYobbo
March 15, 2009, 10:01
The problem with this rifle is the bolt is loose enough that the roller jumps out of the op rod when fired

thats an op rod problem
check the rod guide under the barrel for correct alignment also check the lug on the op rod that goes in the track in the receiver for damage or wear

falbuff
March 15, 2009, 10:41
the rod guide under the barrel looks to be in alignment the op rod shows some ware also it seems the bolt has a little more slop than it should is that normal.

Warbirds Custom Guns
March 16, 2009, 02:05
Originally posted by Survey Punk
All you need is a go and no-go headspace gauge. Bolt needs to be stripped.

JB
I've said it before & I'll say it again. There's more to it than just headspacing a USGI bolt.
Chinese receivers vary one to another on the inside of the receiver & a few things need to be checked & fitted as needed.
I have posted pics in the past of many differences in Chinese receivers.
Chinese bolts are a little smaller in size compared to USGI bolts, therefore some fitting on 75% of them is needed.

If you plan to use a U.S. made chromed commercial barrel, you'll have to use a USGI bolt to headspace it. Sooner or later a USGI bolt must be used as Chinese made barrels are not available, unless you use a non chromed barrel.

Originally posted by Survey Punk
Just close on go and definately not close on no-go.
JB
Not true at all. They can be headspaced using a no-go (Nato spec. go is 1.634) gauge. I've done only a few for those who wanted it for use with nato spec. ammo. Still safe for 308 as well.
I prefer 1.632-1.633
BTW, I also assume you're refering to commercial gauges as Nato gauges would be longer.
If commercial gauges is what ya refer to, the go gauge would be a bit tight for nato surplus ammo.


Originally posted by ActionYobbo
not all the poly bolt were bad. it was just a small batch. do a search and find out if yours is in the bad batch.

No such resource is currently available that indicates which are good & those that are not. I'd love see it myself if in fact there is one.
I only assume that you can provide the source of this info ?????

Celt
April 04, 2009, 10:28
This has always been an ongoing debate. I have owned both Norinco and Poly and never had any problems.

I've asked this question over the years: Show me a pic of ONE Norinco/Poly that has had a catastrophic failure due to the bolt.

I am still waiting.


Celt

mortismaker
April 04, 2009, 15:11
Send it to Warbird and just get it done. I had my done a while ago and it is perfect. I can't say enough about the quality of the work and the professionalism that Warbird has. Top notch.

John Crusher
April 04, 2009, 21:56
IF you feel the need to replace your bolt, I would ONLY have Warbird do it. It will be done correctly with no B.S. I know several people who have used him and I trusted them with my life. That being said, I have never had an issue with either a Poly or Norinco and had to replace only 1 roller after I wore it out.

Warbirds Custom Guns
April 05, 2009, 01:06
Originally posted by Celt
This has always been an ongoing debate. I have owned both Norinco and Poly and never had any problems.

I've asked this question over the years: Show me a pic of ONE Norinco/Poly that has had a catastrophic failure due to the bolt.

I am still waiting.
Celt

There's no debate about it.
You said "have owned". So I assume ya don't anymore.
I guess ya never shot them enough to know what could have happened down the road. :rolleyes:

Those that say "Show me a pic of ONE Norinco/Poly that has had a catastrophic failure due to the bolt". Or "name someone who wore out a "chinese bolt".

I've said it before but, I guess ya didn't read it so I'll post it again.
It's more than just a "soft bolt issue".

It's a long list problems associated with the chinese bolts.
1. It may be soft but, maybe not all of them.
2. Receiver lugs don't match the bolt lugs.
3. Many have long headspace which doesn't allow the use commercial ammo.
4. Chinese bolts are slightly smaller than USGI bolts.
5. One bolt lug on chinese bolt may have more contact than the other causing a misaligned bolt which results in poor accuracy. A USGI bolt correctly installed & lapped increases accuracy by about 75%.
6. Chinese bolts can not be used with USGI or commercial chrome lined barrels. Replacement chinese chromed barrels are not available.

BTW Celt, have you ever made a chamber casting of the chinese barrel ?? If ya did ya would know that the throats are .050-.100 longer than U.S. made barrels. That's why they don't have catastrophic failures with long headspace.
Well Celt. Your waiting is finally over.

vmtz
April 05, 2009, 09:06
Fist off, I have never heard a bad thing about Warbirds gunsmithing.

As for replacing the bolt, I did it my self. Jerry Kuhnhausen does a very good book, well a shop manual, on building M-14's. The USGI bolt was not a drop in. The receiver was and breech face fact was a bit small. I had to open up the breech face first. Once the the bolt fit the breech face I lapped the bolt in. There are some angles on the bolt lugs you need to watch and you need to keep the bolt perpendicular to the bore.

If I remember correctly, I did a more detailed post about it in the gunsmithing forum.

Fr. Vince

falbuff
April 05, 2009, 15:25
I want to thank everyone for there advice,sent the rifle to Tin@warbirds for the necessary repairs can't wait to get it back.

garandguy10
April 10, 2009, 20:29
Installing a USGI bolt in a Chinese M14 usually takes a bit of work and lapping. It is rare for a USGI bolt to fit right in and headspace without some work.

wildwilly
May 01, 2009, 15:31
It fit right in. Brought the headspace into 308 forester gage go no go range and runs find with GI and surpluse ammo. Lugs look like even contact on the lugs.
A Norinco had to be fitted. So I agree with depends on the rifle.

DrDuc
May 10, 2009, 22:49
I had a Polytech that shot 2MOA with anything. It swallowed a field gauge. I had intended to replace all the critical Chinese bits with GI but sold the rifle in the after election fever. I still have a TRW bolt and trigger assembly, GI barrel and op rod.
I talked to 2 guys in my club who had shot over 10,000 rounds from the Polytech before they notice the groups opening up. Then they had the rifles rebuilt by Fulton or Smith.

sct1886
May 11, 2009, 06:59
Originally posted by ActionYobbo
not all the poly bolt were bad. it was just a small batch. do a search and find out if yours is in the bad batch. I have one thats not in the bad batch and have fired about 7000 rounds and it has no problem at all

What you have stated is correct. Fortunately you had a good one. The problem is they go out quickly. It generally starts with a few malfunctions. I have one that did this and so did my best friend. If I had an unknown Poly-Tech I would change the bolt. I value my tit-scanners more than a few dollars.