Remington 700 question on firing pin - intermittent misfire

D

DH2849

Guest
Hello folks,

I thought I would ask the gunsmithing forum to comment on the photo and the problem as I'm sure the correction is going to require a gunsmith to correct the problem.

This past weekend was enjoying dispatching prairie dogs to the great prairie in the sky when a problem came up. Out of roughly 150 rounds fired from a Remington .222 - there were 3 that failed to fire. On the first one the thought was "Dang - somehow missed getting the powder into this one" and then quickly cycled another round to connect with the dog barking an alarm. On the second misfire - "What the heck!! I missed two loads??!!" And then again back into game as the battle was raging. The third misfire brought everything to an immediate halt. SOMETHING IS WRONG BOY - CHECK YOUR WEAPON!!. After inspecting the three rounds carefully the rifle was promptly declared "out of service" and put into it's case. At the reloading bench - the cartridges were partly disassembled and each had it's proper charge - however the primers had not ignited.

You can see in the photo the small indentation in the primers from the pin on the cases that did not fire compared to other cartridges that fired. My question is what may be causing this intermittent concern to occur? I will be taking it to a gunsmith but would like to hear your thoughts please.

Thank you in advance,
Dale

IMG_3860.jpg
 
Dusty Stevens said:
Blanked primer disc in the bolt body or oversizing your brass. How far are you bumping them back?
Click to expand...



This batch had full resize & trim to get all the cases the same size, then they were all annealed as they had never been (bought new machine). Mostly I just neck size with a .002 shoulder bump. I don't shoot hot loads and this brass I have been using since 1996 and only recently had a couple of necks split (hence the machine purchase).

To my untrained eye the firing spring and pin look ok.
 
If the primers were seated full, then the pin velocity may have beeen slow. Clean the pin channel. Install a new firing pin spring. Check the firing pin protrusion with a gauge.
 
Firing pin protrusion should be .030"-.039" on the small rifle primer, .060"-.068" on large rifle primer as per DOD ammo test guidelines . Use a new firing pin spring. If you had a firing pin indent test fixture, a HS GO gage machined for a copper crush cylinder, you should have and indent of .020"-.025" on both sizes.
 
I once had a problem with ignition failure. About 5-10% of primers would not go off. It turns out that the tip of the firing pin was slightly bent. This caused it to travel slow enough that some primers would not go off. Very frustrating until I figured it out.

You should keep in mind that reading the indentations can be misleading. The indentation on a primer that does not go off will always look different even if it was properly struck by the firing pin, because there is no pressure from ignition forming the primer against the bolt face.
 
skeetlee said:
maybe just bad primers? Have you ruled that out yet?? Lee
Click to expand...

Yes I did... however in over 40 years of shooting I have never had even one primer fail.. I'm very fortunate I guess.... and these are "Benchrest" primers. So to have three of them faulty? Very slim odds in my humble opinion.
 
Have you measured the amount of shoulder setback on the cases that failed to fire compared to the ones that did? You stated that you annealed after full length sizing. Sometimes after annealing, the size die needs to be adjusted to avoid excess shoulder setback. If you have been neck sizing for years with no problem and then have misfires after full length sizing it would seem likely that there is a size issue. Do you use a Stony point tool or a similar gizzie to measure the length from the base to the datum line?
 
SGS said:
Have you measured the amount of shoulder setback on the cases that failed to fire compared to the ones that did? You stated that you annealed after full length sizing. Sometimes after annealing, the size die needs to be adjusted to avoid excess shoulder setback. If you have been neck sizing for years with no problem and then have misfires after full length sizing it would seem likely that there is a size issue. Do you use a Stony point tool or a similar gizzie to measure the length from the base to the datum line?
Click to expand...

Bingo!

Combination of too much shoulder setback and freshly annealed cases.
 
You must log in or register to reply here.
Back
Top