Mis-Firing Problems

[Denio]

Last July I ordered three Savage actions Model 12 - RBLP. Had them fitted with PacNor Barrels in 20 Caliber..

Strange thing about them is that all three of them are mis-firing about 10% of the time.

One rifle was for a friend and the other two are mine... we both are using Rem 7-1/2 primers...
The primer strikes are lite on the first strike, and sometimes they will fire on the second try... if they don't fire, the primer strike is deep after three tries.
Don't think they are bad primers because of the lite strikes and definitely different lot # of primers...

Did the Head Space twice on all three rifles and it's set tight.

After the first trip to the range we took the firing pins out and cleaned them and lightly oiled them... On the second trip my two rifles had no problems... about 35 rounds shot through each rifle... Friends rifle still mis-fired...

Third trip yesterday for me and the problem is back...

Went to the range again today after polishing the firing pin area where it goes through the pin up by the bolt face and the problem was worse... mis-fired about 60% of the time...Even tried a new firing pin assy and it mis-fired on the 4th shot...

I am using new brass.. Lake City..

Any Suggestions????

[BillPa]

The primer strikes are lite on the first strike, and sometimes they will fire on the second try... if they don't fire, the primer strike is deep after three tries.

I'll assume with that statement your fully depressing the AT blade?

Discounting ,first of all I'd set the firing pin protrusion to .030"-.035" and then set/reset the overall pin assembly length.

Second I'd make sure the sear moves freely and the trigger over travel isn't set too tight, it needs a bit of over travel or its going to drag on the trigger after its released padding the pin fall.

Just a few things I do or check at this point to start.

Bill

[Denio]

Thanks Bill... I took my Savage Model 10 in 223 and checked the overall length of the firing pin and it was a lot shorter than the new one's in the 20 cal's... set them all the same and popped a few primers in the garage... those worked ok... Back to the range later this week...

How is the firing pin protrusion set? I thought they were a set length and controlled by the shoulder on the firing pin going into the bolt head...

I will update on what happens at the range later this week...

Thanks Again.

[thomae]

Denio, Did you use the search function?
Try that first. If you have no joy, Look here:
http://www.savageshooters.com/content.php?143-Firing-Pin-Protrusion-Data
http://www.savageshooters.com/content.php?158-Savage-Firing-Pins-Bolt-Faces

[BillPa]

I thought they were a set length and controlled by the shoulder on the firing pin going into the bolt head...

Thanks Again.

No, its controlled when the adjustment nut bottoms out on the bolt head shaft on the bench setup.

Bill

[jglover_81]

You might check your brass. I resized some for my 223AI and pushed the shoulder back too far and was having major misfire issues. Once I realized what I had done I havent had an issue since.

[Denio]

Just wanted to thank everyone... Went to the range today, and the problem is solved... Thanks Again.

[Werewolf]

Denio if you don't mind please clarify what you believe solved your problem. Others searching for an answer to their problem will want to know.

[Denio]

I took my Savage Model 10 in 223 and checked the overall length of the firing pin and it was a lot shorter than the new one's in the 20 cal's... set them all the same. I came up with a overall length of 4.792...

I didn't even know that they were adjustable.. I am going to take one apart and see how it functions. Then it will make more sense to me

[BillPa]

I didn't even know that they were adjustable.. I am going to take one apart and see how it functions. Then it will make more sense to me

Lets see if I can help ya a bit. Here are the "guts".
http://i56.tinypic.com/23kcbow.jpg

Of interest, the end of the bolt head shaft, adjustment nut and firing the portion of the firing pin forward of the nut. As I said previously the nut bottoming out on the bolt head shaft stops the firing pin forward travel, the adjustment nut determines the amount of the "bench setup" protrusion. The nut is a right hand thread so turning it left shortens the protrusion, right lengthens it.

The amount of protrusion is different between the bench setup and the pin striking a primer. Typically a primer stops the pin forward movement at in the .018"-.020" range regardless of the bench setup. Any amount over that shortens the pin fall, reduces primer impact energy and may be one of the many reasons for misfires. Of course a bit more is needed to make up for primer seating depth, small variations in cartridge head clearance and etc, so a .030"-.035 is more than sufficient to make up for those variations.

The second adjustment is the overall firing pin length from the face of the protrusion adjustment nut to the cocking piece pin. The pin should have about 1/16" clearance from the bottom of the cocking ramp with the protrusion nut bottomed on the the bolt head shaft. That adjustment is made by turning the cocking piece. Again, it will never reach that point on a primer, but ensures the maximum firing spring compression cocking the bolt.

Any time the protrusion length is changed the overall pin length should also be checked and or corrected.

I'm much better with pictures, butI hope this helps at least a little.

Bill

[Denio]

Bill... Thanks for the info.. I believe I have an understanding now of how the adjustments are done.

I believe the reason for the problem with the three actions were that they were never set from the factory.. Action are machined and then sit on the shelf waiting to be used or shipped out..
If they were install on a rifle at the factory they would have had to be checked for the proper adjustments and test fired..

[BillPa]

If they were install on a rifle at the factory they would have had to be checked for the proper adjustments and test fired..

Proper adjustment? Oh, they were more then likely set to a spec, generally in the .055" range or what is considered the correct optimum length but when I asked some of the best why .055 is "optimum" all ever got was "Well, it is" without any detailed rime or reason why.

Back to your previous post...
"I took my Savage Model 10 in 223 and checked the overall length of the firing pin and it was a lot shorter than the new one's in the 20 cal's... set them all the same and popped a few primers in the garage... those worked ok."

I could fill half a page with all the gory details why, but suffice to say a shorter protrusion will result in increased primer impact energy than a longer one provided its not a ammo issue which is different problem all together.

Bill