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  #21  
Old 01-24-2018, 07:41 PM
.Steve. .Steve. is offline
 
Join Date: Oct 2009
Posts: 833
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Thank you.

That excerpt from the sticky is a machinery function description with a few failure modes noted. It should help identify the real cause of seemingly mystery problems.

The culprits are poorly made factory ammo that has cases that are too long, or, poorly trimed/failure to trim reloaded ammo.

The bare factual machinery description is just that. How the action works.

The consequence of partially locked actions firing is obvious. They either stay shut or not.

(As an aside, I have a theory, just that, as to the cause of some carbine broken bolts. The theory being the or a cause is multiple firing partially locked which un-evenly stresses the right bolt lug. Some but not all fractures seem part plus part rather than all at once. The carbine bolt is a simple rotating flap that seemingly should be strong. The design is complicated by all the little cuts and holes and corners cut in the face that weaken it. Some break.)
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  #22  
Old 01-24-2018, 07:59 PM
Dick S. Dick S. is offline
 
Join Date: Oct 2009
Location: N.E. Indiana
Posts: 13
Default Cold temps

I don't know where you live but if the bolt has grease or heavy oil around the firing pin cold temps will hang up the firing pin or slow it down enough to cause misfires.........is the firing pin clean?
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  #23  
Old 01-25-2018, 03:43 PM
luigi luigi is offline
 
Join Date: Mar 2011
Location: arkansas
Posts: 339
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Quote:
Originally Posted by luigi View Post
I still have occasional misfires so I ordered a new firing pin and hammer spring.
The new hammer spring was 0.5" longer than my old existing one! It took 2 football players and a mule to get that new hammer spring and plunger compressed enough to install! While installing this, the trigger spring came loose and I had to re-install the trigger spring/trigger/sear/sear spring/ and hammer.
WOW. Installing the trigger spring and trigger was tricky....and took a while.
It reminded me of a drunk elephant trying to repair a watch.

I will hang on to the new firing pin untill I find out if the new hammer springs helps. Range trip planned when it warms up a tad.
Did a range trip this morning and the "new hammer spring" did the trick!! No misfires or light primers. Even the surplus 1972 LC ammo that never fired before.... all went BOOM. I fired about 50 reloads and 20 of the surplus Lake City.
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  #24  
Old 01-26-2018, 05:38 PM
Bubblehead751 Bubblehead751 is offline
 
Join Date: Dec 2016
Posts: 128
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Quote:
Originally Posted by luigi View Post
Did a range trip this morning and the "new hammer spring" did the trick!! No misfires or light primers. Even the surplus 1972 LC ammo that never fired before.... all went BOOM. I fired about 50 reloads and 20 of the surplus Lake City.
Can you post the manufacturer and part number of that spring. Took mine out today and still had several light strikes.

Probably ought to buy a bolt disassembly tool and change the firing pin out. At some point I should also go ahead and put a new barrel on. This one swallows a 30-06 cartrige and is all over the place at 100 yards.
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  #25  
Old 01-26-2018, 06:00 PM
luigi luigi is offline
 
Join Date: Mar 2011
Location: arkansas
Posts: 339
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Here you go:

https://www.gunpartscorp.com/products/563370B

https://www.gunpartscorp.com/products/544250
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  #26  
Old 01-26-2018, 06:05 PM
luigi luigi is offline
 
Join Date: Mar 2011
Location: arkansas
Posts: 339
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Bubblehead

I forgot to mention I bought a new criterion barrel from CMP last year and had local gunsmith install it and headspace it.

Numrich also has firing pins:

https://www.gunpartscorp.com/products/542270B

Last edited by luigi; 01-26-2018 at 08:40 PM.
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  #27  
Old 01-26-2018, 06:36 PM
microwaveguy microwaveguy is online now
 
Join Date: Dec 2009
Location: South SF Bay Area
Posts: 941
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Quote:
Originally Posted by luigi View Post
The new hammer spring was 0.5" longer than my old existing one!
Could you count the number of coils on the Hammer spring that you removed. Older springs had 22 coils and the newer ones have 26.5 and there is about 0.5" difference in the two.
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  #28  
Old 01-26-2018, 07:08 PM
luigi luigi is offline
 
Join Date: Mar 2011
Location: arkansas
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Quote:
Originally Posted by microwaveguy View Post
Could you count the number of coils on the Hammer spring that you removed. Older springs had 22 coils and the newer ones have 26.5 and there is about 0.5" difference in the two.
I did not count the coils but my old spring was 2.125" long and the new one
was 2.625"

I will get a count on the springs tomorrow.
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  #29  
Old 01-26-2018, 08:19 PM
microwaveguy microwaveguy is online now
 
Join Date: Dec 2009
Location: South SF Bay Area
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Quote:
Originally Posted by luigi View Post
I did not count the coils but my old spring was 2.125" long and the new one
was 2.625"

I will get a count on the springs tomorrow.
2.125 is about right for a 22 coil spring
2.616 is the drawing spec for the 26.5 coil spring
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Beware of people who are certain they are right. That certainty allows them to justify almost any act in pursuit of their goals. ( Jack campbell , Guardian)
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  #30  
Old 01-26-2018, 09:58 PM
6 Ring 6 Ring is offline
 
Join Date: Apr 2010
Location: South of Atlanta, Ga
Posts: 3,063
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Just remember the many of the part houses are selling new made parts and they are not to GI specifications.
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