I think the cause of these primers being pierced is due to a weak firing pin spring. The ammo is factory. I've looked at the spring and it is not broken. I would appreciate your thoughts.
pierced primers
- Thread starter moosemoose
- Start date
I think the cause of these primers being pierced is due to a weak firing pin spring. The ammo is factory. I've looked at the spring and it is not broken. I would appreciate your thoughts.
Spotcheck_Billy
As I'm sure you know a pierced primer is usually a sign of too much pressure, but a firing pin with a damaged tip can also pierce a primer on a safe load.
Forum Boss
Administrator
Mic,measure) your web dimension at the top of the extractor groove and then .150" up towards the neck.
Compare numbers for unfired, fired with normal primers, and fired with flowing primers or pierced.
That may give us a sense of weather there is a pressure problem.
Also, how is the headspace on this gun?
If those cartridges are bouncing front to back, that will cause strange effects.
Compare numbers for unfired, fired with normal primers, and fired with flowing primers or pierced.
That may give us a sense of weather there is a pressure problem.
Also, how is the headspace on this gun?
If those cartridges are bouncing front to back, that will cause strange effects.
First of all thanks for the suggestions and coments, and I apologize for the lack of information as I was in a rush the day I posted this thread.
The rifle is a Winchester model 70 in .264 magnum, it was my Dad's rifle made in 1965. He gave it to me in '86. Just guessing I believe that there have been less than 300 rounds shot during the life of the rifle.
I wanted to start reloading for it so I purchased some ammo from Remington, which by the way the bullet diameter is only .257 or 6.5mm, .264 x 25.4 =6.7mm)
The picture is of the 6 rounds I shot I don't recall which order they were in. There is some leakage around the 2 primers in question.
I thought of the firing pin spring because the one primer looks like an "outie belly button" like the pressure blew it back into the bolt, the 2nd primer looks like the same thing but it broke as it entered the bolt face.
For all I know theses two shells were hot and the pressure blew out the primers.
I measured just above the belt and all unfired cases were .505".
On the fired cases the measurement was .509", as I continue measuring toward the shoulder the case expands to .515" at about the point where the web tapers into the body of the shell approximately .100" above the belt.
I can also see the shiny ring associated with case stretch.
My case length gauge hasn't arrived yet so I have no way of measuring the case, or chamber.
Again gentlemen I appreciated your suggestions...
The rifle is a Winchester model 70 in .264 magnum, it was my Dad's rifle made in 1965. He gave it to me in '86. Just guessing I believe that there have been less than 300 rounds shot during the life of the rifle.
I wanted to start reloading for it so I purchased some ammo from Remington, which by the way the bullet diameter is only .257 or 6.5mm, .264 x 25.4 =6.7mm)
The picture is of the 6 rounds I shot I don't recall which order they were in. There is some leakage around the 2 primers in question.
I thought of the firing pin spring because the one primer looks like an "outie belly button" like the pressure blew it back into the bolt, the 2nd primer looks like the same thing but it broke as it entered the bolt face.
For all I know theses two shells were hot and the pressure blew out the primers.
I measured just above the belt and all unfired cases were .505".
On the fired cases the measurement was .509", as I continue measuring toward the shoulder the case expands to .515" at about the point where the web tapers into the body of the shell approximately .100" above the belt.
I can also see the shiny ring associated with case stretch.
My case length gauge hasn't arrived yet so I have no way of measuring the case, or chamber.
Again gentlemen I appreciated your suggestions...
Considering the things you've said and the fact that it's a hot caliber I immediately start wondering if there's a buildup of fouling in the bore causing an overpressure. You may have already taken care of this but if not I would scrub the heck out of that bore and consider some good copper solvent. Then see what happens. Also try some other ammo if that's not the case. The factory can make some bad batches.
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