Primer "Strength" or "Force"

[BruceB]

Today my wife exhumed my old Speer #7 Manual from some dusty nook. On the flyleaf, I had written: "BruceB, Yellowknife NWT, August 1968" ...so, I've owned it for a while.

Reading through the instructional part of the manual, I was impressed by how little has changed. Articles by Nonte, O'Connor, Grennel, Forker, Powley etc still make excellent reading.

Then I came across a little gem from CCI, that being a table containing the foot-pounds of force generated by each of their various types of primers. This data is obviously pretty old, but the types are exactly the same, and I've never noticed any change in the CCI's I've used in the meantime, which amount to hundreds of thousands over the decades.

"A uniform initiating blow of 0.45 foot pounds was used to fire all primers. Values are energy imparted to a piston in a test cylinder."

"By actual copper crusher test, the CCI 250 Magnum primer produces a pressure of 25,000 psi when fired in a small closed chamber. This is an essential function of a primer in igniting smokeless propellant powders."

Now, the figures provided from CCI for energy developed by each type of primer:

Small Pistol #500 ----------------5.50 ft lbs

Small Pistol Magnum #550-----8.80

Small Rifle #400-------------------6.00

Small Rifle Magnum #450--------7.20 (lighter than sm pistol magnum! BB)

Large Pistol #300---------------- 7.10

Large Pistol Magnum #350------9.15

Large Rifle #200------------------9.20

Large Rifle Magnum #250--------9.45

Interesting, yes????

[Topper]

That brings up another question.
Winchester sells a large pistol primer that is rated for both standard and magnum.
Is there any similar published data for this primer?

[felix]

That needs to be done with all primers. Plus a table of the amount of calories, or some other heat measure, generated by each. And, perhaps, another table depicting the speed of the shock wave front. I bet, from intuitive experience, that the correlation coefficient between each pair of curves would be no more than circa 0.65 or so.

I wonder if CCI still has that equipment and would allow one of us retired folks to operate it so one or more of these tables can be published? ... felix

[ron brooks]

George Nonte is one of my favorite "gun writers", my favorite on reloading, yet I hardly ever hear him mentioned. His Modern Handloading was the first real volume on handloading I ever had. Wish I had had it sooner, would have saved me some silly mistakes.

Ron

[454PB]

Many years ago there was an article in The Handloader magazine where the author made up a crude but effective method of measuring primer force. It was a rod with measurement hash marks along the length, and a piston attached to the end that butted up against the chamber. He then used the available primer selection at the time and documented the distance each primer ejected the rod. I have every Handloader magazine I've received for the last 34 years, maybe I can locate the article when I'm very bored.

I bought a pile of old CCI primers at a garage sale, all of them had the purchase dates written on the bricks. What amazes me is that the oldest (dated 1976) function exactly as the present day primers.

[Mk42gunner]

As long as primers, or ammunition for that matter, are stored in decent condtions they will last a surprisingly long time. I have shot or ran the range to expend several pallets or 7.62 Nato through M-14's, that was made from 1964 to 1968 it was in garand clips. We never had any misfires with it. Most of it was Winchester, some from Twin cities (I think), and a very small amount of Remingtonthat was in belts for an M-60.


Robert

[4060MAY]

http://castingstuff.com/primer_testing_reference.htm

[Topper]

Thanks for the link.
I just bookmarker it for future reference;)