Soft primer strike problem is rearing its head

[Nor Cal Mikie]

Well said Fred!!:cool::cool:

[tomme boy]

Your wrong FRED. CCI states the anvil is spaced farther away on the 41 primers.

[Robinhood]

Your wrong FRED. CCI states the anvil is spaced farther away on the 41 primers.


Tomme, I am interested in this. I went to CCI's site but the only thing I could find was that they are built to Military spec's. Can you provide a link. Thanks


I did Find this in a technical article however;
CCI/Speer Technical Services says: "The CCI 400 primer does have a thinner cup bottom than CCI 450, #41 or BR4 primers... [with] the CCI #41 primer... there is more 'distance' between the tip of the anvil and the bottom of the cup."

Credit to John Barsness "A primer on Primers"

[tomme boy]

You know what?? It is no longer on their site. It used to be. And it gave the difference of the depths as well.

[Robinhood]

I found the mil spec references but I never could find the drawing. I had never seen the reference to the #41 with regards to the spacing between the cup and anvil until I uncovered the article I mentioned above.

[sharpshooter]

Instead of relying on what you've seen and heard, has any one of you guys ever dissected primers and actually measured them?

[Robinhood]

Ive done a lot of things but I have never done that?

[sharpshooter]

Well........I have, and I'll stand by my statements.

[wbm]

Good idea.

[Robinhood]

Well........I have, and I'll stand by my statements.


OK, but there is this lingering question. How did you measure between the anvil and the bottom of the cup? Asking for a friend....:o

[wbm]

LOL. Carefully?

[sharpshooter]

Well, first you measure the over all height. Then you remove the anvil and measure it's height. Once you dig out the priming charge from the cup, you can measure it's thickness. This is done using a height gauge and a 1/8" ball bearing, that way you are measuring the thickness on the primer face, not on it's sides. They rest is simple math, and you must figure in how much crush to get the primer approx .004" below flush.
You will find there is a big tolerance in primer specs, and in the end game, they ALL end up within tolerance.

[gumbo333]

Probably no one is interested but many years ago like 35 or 40, Ric Jamison who at that time was a staff writer for Shooting Times did about the best article on primers that was ever written. Comparing and testing nearly every type of rifle primer. Pictures of how far out the fire went. Not sure how to ever look it up but well worth it if you can.

[wbm]

I remember that!

[HRGX]

Hello, I hope that I can help. I am an accredited gunsmith in southern Alberta. A client brought me an Axis in .223 Rem with exactly the same problem. Inconsistent firing pin indents on the primer, thus misfires. Upon very close inspection of the bolt fully disassembled, I notice drag marks on the firing pin at the point where it passes through the 1/4″ cross pin which secures the rotating and fixed bolt heads. I checked firing pin runout on my lathe at the point where is passes though the cross pin. This measured 0.095″. The hole through the pin measures 0.105″ this allowing a 0.010″ clearance. The firing pin runout measured 0.013″ with a digital dial indicator. This would then mean a 0.003″ interference which can cause the drag marks and restrict proper striking. I opened up the cross pin hole from 0.105″ to 0.147″ using a carbide #26 drill bit. The client has reported back to me and indicated that a dozen rounds did not show any more problems. The cross pin is actually a very loose fit. When pressure is relieve from the wave washer, the pin can drop out on it’s own. As such, if the pin is not perfectly lined up center of bore, it can cause interference with such a small clearance of 0.010″. Furthermore, the pin being such a loose fit, can rotate again causing interference. As a side note and warning to do it yourself guys. The drill MUST be carbide as the pin is hard, standard tool steel bits may not cut it. And it’s a precision job, the original hole must be perfectly centered in the vice jaws. I use a milling machine to do this job and not a drill press and certainly not a cordless. Good luck.

[prdatr]

Hello, I hope that I can help. I am an accredited gunsmith in southern Alberta. A client brought me an Axis in .223 Rem with exactly the same problem. Inconsistent firing pin indents on the primer, thus misfires. Upon very close inspection of the bolt fully disassembled, I notice drag marks on the firing pin at the point where it passes through the 1/4″ cross pin which secures the rotating and fixed bolt heads. I checked firing pin runout on my lathe at the point where is passes though the cross pin. This measured 0.095″. The hole through the pin measures 0.105″ this allowing a 0.010″ clearance. The firing pin runout measured 0.013″ with a digital dial indicator. This would then mean a 0.003″ interference which can cause the drag marks and restrict proper striking. I opened up the cross pin hole from 0.105″ to 0.147″ using a carbide #26 drill bit. The client has reported back to me and indicated that a dozen rounds did not show any more problems. The cross pin is actually a very loose fit. When pressure is relieve from the wave washer, the pin can drop out on it’s own. As such, if the pin is not perfectly lined up center of bore, it can cause interference with such a small clearance of 0.010″. Furthermore, the pin being such a loose fit, can rotate again causing interference. As a side note and warning to do it yourself guys. The drill MUST be carbide as the pin is hard, standard tool steel bits may not cut it. And it’s a precision job, the original hole must be perfectly centered in the vice jaws. I use a milling machine to do this job and not a drill press and certainly not a cordless. Good luck.

Thanks for taking the time to post this I am sure it will help some members sought out their particular problem further.