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USGI Op Rod Spring ?

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Old March 23rd, 2011, 02:42 PM   #1
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USGI Op Rod Spring ?

Who has NOS USGI M14 Op Rod Springs?
Thanks guys

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Old March 23rd, 2011, 02:49 PM   #2
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op rod spring

Sure you want to go that route? Tubb's springs (Superior Shooting Systems) are good for a half million cycles and withstand much more heat. Comes with hammer spring also for about 22 bucks. If not, try M14 parts.com or RA parts. Both are site sponsors and good people!

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Old March 23rd, 2011, 02:56 PM   #3
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I have a couple of tubs and I even bought a couple from Fuloton. I am not sure if the tubs do what they claim I have faith that they do I plan on getting them for my next two builds as well. I have seen GI ones being sold on GB in lots of 10 or so I am not sure if they are NOS. If you want o eliminate any doubt grab a tubbs. Off topic I was not happy with there AR spring it was too heavy duty and I ran into short stroking on my varmatch AR build. I will give it a try and see if it works in my A2 set up.

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Old March 23rd, 2011, 05:03 PM   #4
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Fred's Stocks also carries them for cheap -

Of course (as is dicussed in another thread), you'd best be prepared to wait quite a while for delivery. They are notoriously slow. I got zinged pretty good on shipping, so maybe it wasn't such a deal in the long run.

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Matt

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Old March 23rd, 2011, 05:16 PM   #5
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Smile Op Rod Springs

We have them at Shooters Den. They are original new GI springs. I use them in my personal rifles and they will work for many thousands of rounds.

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Old March 23rd, 2011, 07:05 PM   #6
 
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What are the min and max lengths for the USGI spring and about how many rounds before it gets "shortened" or starts to take a set?

Is this something people should stock up on or will the spring last longer than most shooters (at least us old timers)...

Thanks from Quicksilvergoat
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Old March 23rd, 2011, 09:54 PM   #7
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Quote:
Originally Posted by pastprime View Post
What are the min and max lengths for the USGI spring and about how many rounds before it gets "shortened" or starts to take a set?

Is this something people should stock up on or will the spring last longer than most shooters (at least us old timers)...
From Lee Emerson's Book.......

Quote:

The USGI drawing B7267079 for the operating rod spring is illustrative of the detailed
requirements typical of M14 parts production. Some of the drawing B7267079
specifications are described below.
The operating rod spring material was 17-7 precipitation hardening stainless steel wire
per military specification Mil-W-46078 and manufactured under military specification Mil-
S-13572 Type 1 Grade B. This material was chosen for the operating rod spring in 1952
as part of the T44 rifle modifications. The physical dimension and performance
requirements were as follows: wire diameter equal to 0.054 " + or – 0.001 ", coil outside
diameter of 0.4575 " + or – 0.0025 ", free length of 15.23 ", a total of 104 coils, and the
direction of the helix must be right-hand wound with closed ends.
The operating rod spring formed by coiling cold drawn wire had to be heat treated as
follows: age hardened at 900 degrees Fahrenheit for one hour then air cooled. After that,
the operating rod spring was heat set by heating at 700 degrees Fahrenheit for twenty
minutes with the spring compressed to a length between 5.9 " and 6.0 ". Heat setting a
spring improves the stress relaxation during use. Age hardening is used to increase the
strength and hardness of manufactured parts made from certain alloys, e.g., copperberyllium
and 17-7 cold drawn stainless steel. Each material responds differently to the
age (precipitation) hardening process based on a combination of time, temperature and
the amount of cold drawing from the initial rod size into the final wire diameter.
Depending on the material, the toughness, corrosion resistance, fatigue strength,
electrical conductivity or thermal conductivity can be improved upon by stopping the
hardening procedure before or after the time needed to achieve maximum strength. By
age hardening and heat setting the operating rod spring, service life was significantly
increased.
The operating rod spring, like other compression coil springs, was designed with a given
spring rate. The spring rate, or stiffness, is defined as the amount of load (force) needed
to compress the spring one inch. The lower the spring rate the softer the spring. After the
operating rod spring had been heat treated and heat set it was compressed to solid
length three times and then load tested at several specific lengths. These tests verified
the operating rod spring met the design spring rate. The design spring rate for the M14
operating rod spring was 1.95. When the operating rod spring was compressed to a
length of 10.97 " the applied load had to equal 8.13 pounds + or – 0.81 pounds. When
the operating rod spring was compressed to 6.42 " the required load was 17.00 pounds +
or – 1.69 pounds.
When the operating rod spring was compressed to the minimum operating length it
measured about 7.19 " long with an applied load less than 16.00 pounds but sufficient to
engage the bolt lock. The USGI drawing B7267079 for the operating rod spring specified
a maximum length of 5.78 " for the solid compressed length. The design and
manufacturing process ensured the USGI M14 operating rod spring would function
properly for thousands of cycles. It also means that the minimum force necessary would
always be exerted on the operating rod spring guide, and consequently, the magazine full
of life sustaining ammunition. The M14 rifle enthusiast or collector should proceed with
caution when hearing the term “mil-spec” in casual conversation with such detailed
design, manufacturing and testing requirements for USGI M14 parts.
Aloha, Mark

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Old March 23rd, 2011, 10:27 PM   #8
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If you go GI get one from Ted you will want to shoot yourself in the foot if you order from Freds. there was a long thread regarding feedback on "Freds" if you care to read it. From what I read a GI spring should be golden through 5000 rounds before you might need to change it.
Ted is a sponsor on the forum and I for one try and support our sponsors. He is always willing to answer PM with questions.

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Old March 23rd, 2011, 10:29 PM   #9
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Quote:
Originally Posted by pastprime View Post
What are the min and max lengths for the USGI spring and about how many rounds before it gets "shortened" or starts to take a set?

Is this something people should stock up on or will the spring last longer than most shooters (at least us old timers)...
I just changed the op rod spring on one of my rifles. I started getting FTF (feed) issues. It is always the second to last round of mag that wouldn't chamber. I knew it was the rifle and not mags becaused the mags functioned 100% in my other rifle.
I am the third owner of this rifle so I don't know total round count on this spring, but I probably got 1500 through it. The new op rod spring measured 3/8" longer than the one I took out.
I bought four op rod springs the last time I was at the Reno gun show because I got two rifles, the price seemed right, and I just love buying M14 stuff.
An extra op rod spring or two, is something you should have on hand, IMHO.......

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Old March 25th, 2011, 08:08 PM   #10
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Quote:
Originally Posted by Ted Brown View Post
We have them at Shooters Den. They are original new GI springs. I use them in my personal rifles and they will work for many thousands of rounds.
Ted,

For a rifle intended for match shooting at the tune of 600+ rounds a month, including training, at what round count do you suggest replacing the GI spring?

Thank you.

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Old March 25th, 2011, 08:30 PM   #11
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I've used Tubbs in the past and like them very well. I had an extra, so I put it in my SAI rifle. That and a Sadlk guide rod sure butters things up. Last GI spring I got was from Claude at RA parts for around $10, and it was indeed new. Give him a shout.

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Old March 26th, 2011, 02:04 PM   #12
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Springs

I've used GI op rod springs exclussively in all my rifles. I am a Master class competition shooter. The only time I have had a problem with my op rod spring was when I installled a used spring which became weak after about 7 or 8 years of use. At that point it failed to keep the spring guide engaged in the magazine under recoil. The mag would drop down in front and the next round would jam against the breach face. No problems after replacing the spring with a new GI part. By the way, springs are cheap.

Gi springs work great as do Tubb and wolf springs. You can't go wrong with any of them.

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