Post by FED UPOh heck anyone can make an AK-47 !
Post by GunnerThough the Norinco copy of the M1-A has been noted for very
spotty heat treatment of the bolt and receiver.
Yeah. What happens is that after about 500 rounds you've found that
the
hot gases had almost completely blasted out the chamber. The round now
rattles around
after the bolt has closed.
Blink blink...huh???? Hot gases are contained by the cartridge case
in the chamber. Unless you have a case failure..Not a Good Thing ©
Read about guns in some Mickey Spillane book or something?
The issue is locking lug setback and dimensonal issues with some of
the bolts. Norinco and Poly Technics had some problems..very spotty
record.
Post by FED UPOf course you take your life into your hands shooting it like that.
But quite frankly those people that bought that gun...deserve what
they got.
Why? Because they bought a firearm that was in their price range?
Lets look at what the experts have to say on the subject..shall we?
Heres what Fultons has to say on them.
"Clint, tell us about the Chinese M14S
I'd be happy to go through this. Here's the scoop:
1. The locking lug helix (surface contour) of the Chinese bolt does
not agree/match the locking lug helix of the receiver. Thus, the bolt
locking lug surfaces only partially contact the receiver locking lug
surfaces. As you fire the rifle, the bolt will "collapse" back onto
the locking lugs of the receiver until "enough" surface contact is
engaged to stop the rearward force caused by the 50,000 PSI or so that
is produced on each firing. As the bolt moves rearward, headspace is
lost. Often/mostly/always massive headspace loss occurs. I have seen
Chinese bolts that close & move back & forth with a field gauge. I
have witnessed headspace readings estimated (no gauge long enough to
be certain) at greater than 20 thous. beyond Go. G.I. bolt's will also
"collapse" when receiver locking lugs are not correct (commercial
receivers sometimes have poor locking lug surfaces which is why we at
Fulton Armory always hand lap every bolt to every commercial receiver
to ensure excellent engagement before we install/set headspace),
though they move rearward more slowly due to better heat treat &
steel. The fact that the Chinese bolts are very soft, amplifies the
problem. BTW, the locking lug helix of the Chinese receiver does
agree/match the helix of the G.I. M14 bolts quite nicely. I have never
had to hand lap a G.I. bolt for more than say, 15-20 minutes to get a
beautiful engagement. It's quite odd. It's as though someone ground on
the Chinese bolt lugs with a handtool.
2. The Chinese bolt is "too long" as it relates to the firing pin
bridge of the receiver, which retracts the firing pin on loading. As
the Chinese bolt moves reward, the firing pin tail also moves reward.
So much so that the firing pin bridge does not effectively/at all
retract the firing pin! I have seen Chinese rifles where the firing
pin did not retract at all. This is quite dangerous. Add to this bolt
"geometry" problem the fact that the trigger & sears, & hammers are
also way too soft (hammer fall will occur) one can see the train wreck
ahead.
A. One thousand rounds through an M14 is nothing. I have customers who
do this in a month. The whole point of possessing fine military rifles
is that their design, properly executed, provides for a durability &
reliability virtually unknown in commercial products.
B. That a rifle has not failed catastrophically, nor a wing fallen
off, is hardly a measure of acceptability, safety or serviceability.
C. The vast majority of Chinese M14's that come into our shop have
excessive headspace, among other maladies. A very few have had too
tight a headspace, which is quite odd.
Fulton Armory builds Service and Competition Grade rifles on Polytech
and Norinco receivers from customer-supplied rifles. The result is a
superlative M14-type rifle with a forged receiver, as close to GI as
you can get.
Note to Walt: The barrel must be replaced to allow for a G.I. bolt to
fit, and even then, the receiver needs relieving to safely accept the
bolt! THIS IS A VERY IMPORTANT POINT! Also, the Hammer, Trigger & Sear
need to be replaced.
Our package should be done all at once, or not at all. You would not
believe the horrendous examples that come into the shop that were
"worked on" by the local "Gunsmith," trying to fit the G.I. bolt. One
needs to know what to grind, and even more importantly, what not to
grind. You really would not believe it. You're too trusting to believe
what I've seen, Walt
--Clint McKee
A postscript from Kirk Hays:
Having owned several of the Chinese M14S rifles, and having a set of
M14 receiver gauges available to me, I have independently confirmed
what Clint says about the receiver geometries. The Chinese receivers
are dimensionally as good as TRW rifles in the collection of a friend.
Period.
The finish on the Norinco receivers is rough on non-functional
surfaces - they are ugly, and Polytech receivers are only slightly
better.
John Kepler has inside information that the DCM was actually looking
at using Chinese receivers for providing M14 rifles to Service Rifle
competitors, and access to a steel analysis done on the recievers,
showing it to be 5100 steel, which is a very good alloy for receivers,
but a bit difficult to work.
--Kirk Hays
More on the Chinese bolts from Clint:
The Chinese bolts have a great deal more problems than just the heat
treating. Incidentally, whether a part is cast or forged has nothing
to do with whether they need to be heat treated. These bolts could be
transmutated into Kryptonite, but they will still be dangerously
substandard.
The problems include:
The bolt's locking lugs are cut wrong !The helixial angles are dead
wrong, and thusly, they do NOT properly contact the opposing
receiver's locking lugs. A very bad condition, as headspace will be
lost over time. Sometimes, in only a few hundred rounds! The bolt sits
very far back and away from the barrel mouth, and thus, provides very
poor support to the cartridge case at its base. Bear in mind, this has
nothing to do with headspace (this condition can exist even with
proper headspace). The "closer" a bolt fits to the barrel mouth, the
better the support of the case. Over the years, improperly
manufactured barrels have shown us what can happen, even with proper
headspace, when the cartridge's base is not properly supported: total
case failure with catastrophic results. In the Chinese rifle example,
it's the bolt sitting too far back on a proper barrel!
Next, because the bolt sits so far back in the receiver, the firing
pin tail (which exits at the rear of the bolt body) is also too far
rearward and thusly, the firing pin is not properly retracted by the
receiver's firing pin bridge.
If you ever have an opportunity to examine a Chinese rifle, remove the
op rod, and take notice of how far the bolt can move back & fro, while
in battery. In many of these rifles, it's scary. Naturally, how far it
will move will depend on how many rounds have been fired and just how
bad the bolt was originally.
So, IMHO, forget spending a bunch, or a little, money on "heat
treating" the Chinese bolts.
--Clint McKee
"If thy pride is sorely vexed when others disparage your offering, be
as lamb's wool is to cold rain and the Gore-tex of Odin's raiment
is to gullshit in the gale, for thy angst shall vex them not at
all. Yea, they shall scorn thee all the more. Rejoice in
sharing what you have to share without expectation of adoration,
knowing that sharing your treasure does not diminish your treasure
but enriches it."
- Onni 1:33