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Discussion Starter · #1 ·
Ok guys. This one is a good one.

68 worked perfect for 6-8+ years. Fired SSA and Federal without a problem. Then it started light hits no fire on just the SSA rounds, Federal's worked fine. So I was thinking that there was a problem with the SSA ammo. I stopped using SSA and only used Federal ammo. Then about a year later or so I started to get light hits on the Federal ammo also. So I started to look at the gun. I found that the firing pin OAL was 3.279" called the manufacturer and gave them my findings and got another FP with OAL of 3.284". I have not gotten to the range with it, with the new FP so I do not know if that is the fix. The firing pin does not look like it has a broken tip.

I have an extended FP with OAL of 3.291" but I do not want to go there unless I have to. I will try to get to the range this week to test.

Any other ideas?

Thanks
Guys
 

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Firing pins wear like any other component, but I would check that the pin can move freely in the BCG. Might just be carbon build up inside the bolt. If it can move freely, then either the pin is worn, or something is wrong with the hammer on your trigger.
 

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Discussion Starter · #3 ·
Firing pins wear like any other component, but I would check that the pin can move freely in the BCG. Might just be carbon build up inside the bolt. If it can move freely, then either the pin is worn, or something is wrong with the hammer on your trigger.
I did a quick type up on this last night so I did not add everything to it. sorry!

Bolt is clean and I found and got Brownells firing pin protrusion gauge
080-216-013WB
AR-15/M16 Firing/Pin Gaug

I have not checked it with this gauge but I will in the next few days before I go to the range with it. Both with the 3.279" and the new 3.284" pin. This 68 got put in the safe and on the back burner for a while and I am just getting back to fixing it now.
I have looked at the hammer and I don't see anything wrong, I have used a hammer drop block
080-953-000WB
AR-15 Hammer Drop Block

and all seems to be working. I can not find a gauge type hammer drop block that will tell me how hard the hammer is hitting or I would have one of those.

I have a wolf heavy hammer spring also, but I do not want to change more then one thing at a time so I know what the problem is and when it is fixed.
 

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I’d clean the bcg and try the new firing pin. Firing pins do wear, and I’ve replaced a couple. I’ve only used extended pins on steel cased ammo, and think they may pierce a primer on brass cased ammo. The heavy duty hammer spring will definitely make your trigger pull weight heavier.
 

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What trigger are you using. My first thought was a worn or bad hammer spring. If firing pin protrusion is within specs I would try replacing the hammer spring with a standard weight spring. The hammer spring does has much more effect on trigger pull weight than the trigger spring. The trigger spring is basically just a return spring.
 
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Discussion Starter · #6 ·
What trigger are you using. My first thought was a worn or bad hammer spring. If firing pin protrusion is within specs I would try replacing the hammer spring with a standard weight spring. The hammer spring does has much more effect on trigger pull weight than the trigger spring. The trigger spring is basically just a return spring.
Trigger is LaRue two stage. I do not think that the hammer spring is bad. I was looking for a hammer drop block that has a gauge that would tell me how hard the hammer was hitting but I have not been able to find that animal anywhere. If someone knows of one please let me know, I will buy one.

The loss of .005" on the FP is most likely the problem but I will not know until I use the firing pin protrusion gauge and test fire at the range.
 
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