C.U.P. Ever wonder what those little copper crush pellets look like?

tark

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A guy walked into the Rock Island Arsenal museum today asking if we wanted this: A box of the copper crush pellets used in pressure testing. It is dated, as can be seen in the first picture, at the beginning of WWII. I have always wondered what these things looked like. They are about a tenth of an inch in diameter and about 3/5 of an inch length. Folded, in the box, was a chart stating what the breech pressure was determined by the amount of crush. Unfortunately, the paper was damaged, but most of it is legible.

An interesting bit of history, at least indirectly related to firearms themselves.
 

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The size "C" government coppers are .225" diameter and 0.400" long. They are still used for measuring striker indent and for some pressure measurements still required to be measured via radial copper rather than piezoelectric.

Olin is the sole producer of them these days. The last time I bought any the minimum order was 1000 coppers. Their cost in 2001 was $1 each, due to the stringent manufacturing requirements.
 
The size "C" government coppers are .225" diameter and 0.400" long. They are still used for measuring striker indent and for some pressure measurements still required to be measured via radial copper rather than piezoelectric.

Olin is the sole producer of them these days. The last time I bought any the minimum order was 1000 coppers. Their cost in 2001 was $1 each, due to the stringent manufacturing requirements.
That is fascinating! Thanks for that info! I suspect that you may have considerable knowledge in this subject matter.

Since you are pretty new here:

Welcome to the forum!!
 
Highly interesting, and thanks for posting. This is the first time I have even seen any of those things. I could sure see that as a part of the Rock Island Arsenal museum; especially with the early WW2 dating.
 
There was a small .146" diameter crusher used for .22 Rim fire and small caliber pistol rounds and a lead .225x.500 lead crusher used for shotgun, mortar boosters, Kaufman starter cartridges for radial piston engines and explosive bolts for aircraft ordinance.
 
The size "C" government coppers are .225" diameter and 0.400" long. They are still used for measuring striker indent and for some pressure measurements still required to be measured via radial copper rather than piezoelectric.

Olin is the sole producer of them these days. The last time I bought any the minimum order was 1000 coppers. Their cost in 2001 was $1 each, due to the stringent manufacturing requirements.
For the the Government, 0.04010 -0.0020" by 0.2265 - 0.0020 to be exact:

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For civilian use, 0.2260 -0.0005/+0.0010" by 0.400 +/- 0.0010"
Untitled.jpg
 
There was a small .146" diameter crusher used for .22 Rim fire and small caliber pistol rounds and a lead .225x.500 lead crusher used for shotgun, mortar boosters, Kaufman starter cartridges for radial piston engines and explosive bolts for aircraft ordinance.
The .225 X .500" cylinder is the size "A" pressure cylinder. If in copper, it was for medium and heavy cannons.

The 0.146 X 0.400" size is the Government "D" cylinder and for pistols and revolvers.

There is also a 0.3125" pressure sphere.
 
Mods, If this is not QUITE up to the standard for posting, feel free to 86 it.

A guy walked into the Rock Island Arsenal museum today asking if we wanted this: A box of the copper crush pellets used in pressure testing. It is dated, as can be seen in the first picture, at the beginning of WWII. I have always wondered what these things looked like. They are about a tenth of an inch in diameter and about 3/5 of an inch length. Folded, in the box, was a chart stating what the breech pressure was determined by the amount of crush. Unfortunately, the paper was damaged, but most of it is legible.

An interesting bit of history, at least indirectly related to firearms themselves.
What you actually have is a box of Government Size "B" pressure test cylinders. These are for 30mm through 3 inch (as I remember).

The Size "B" and Size "A" cylinders are the same dimension and tolerance, the difference is calibrated range for a fixed crush on the calibration sheet (shown in the OP). To qualify a lot, you took 20 of them and put a special test fixture and put 300 pounds on it, the resulting crush should equal 9,000 "psi" as shown in the attached calibration sheet. The test was repeated increasing the load by 200 pound with a crush equal to 15,000 psi, and so on to 2,500 pounds equaling 75,000 psi. The average and the standard deviation was calculated for all that data. If the results met the requirements in MIL-C-20109 the lot was accepted.

That is one reason these are so expensive, the minimum lot sample size per MIL-C-20109 is 450 samples. at least 400 cylinders to go through the test above (there are 20 pressure steps) and 50 for chemical/physical properties verification, and retest, if needed.
 
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The .225 X .500" cylinder is the size "A" pressure cylinder. If in copper, it was for medium and heavy cannons.

The 0.146 X 0.400" size is the Government "D" cylinder and for pistols and revolvers.

There is also a 0.3125" pressure sphere.
Sounds like we may have worked at some of the same places, though maybe at different times...
 
Old school equipment and methods still prevail in the aviation ordnance business. Though mostly used up since GWOT there still exist some aircraft which drop plain "dumb" gravity bombs without JDAM kits, that are older than the aircrews flying them and were new when their grandfathers wore brown boots with the uniform. The B-52 and A-10 are the surviving USAF examples.
 
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Old school equipment and methods still prevail in the aviation ordnance business. Though mostly used up since GWOT there still exist some aircraft which drop plain "dumb" gravity bombs without JDAM kits, that are older than the aircrews flying them and were new when their grandfathers wore brown boots with the uniform. The B-52 and A-10 are the surviving USAF examples.
Another example!
I was really surprised when the US military got rid of the 1911. Simple to use, maintain, and repair. I figured they would soldier along with the old school pistol for at least 50 more years just cause the old guard that were in charge dislike change.
 
Old school equipment and methods still prevail in the aviation ordnance business. Though mostly used up since GWOT there still exist dumb bombs and aircraft which drop that are older than aircrews flying them and were new when their grandfathers wore brown boots with the uniform. The B-52 and A-10 are examples.
How old do you think the oldest F/A-18E Super Hornet is?

How about the newest F-15C?

How old is the F-22?

Full rate production of the F/A-18E/F began in 1999, 25 years ago. The F-15C production halted in 1986, the last C model was delivered around 1989. The newest F-22A is about 10 years old.

Our entire fleet is getting old, both technologically, and practically.
 
How old do you think the oldest F/A-18E Super Hornet is?

How about the newest F-15C?

How old is the F-22?

Full rate production of the F/A-18E/F began in 1999, 25 years ago. The F-15C production halted in 1986, the last C model was delivered around 1989. The newest F-22A is about 10 years old.

Our entire fleet is getting old, both technologically, and practically.
Consider the dinosaur view. Back when I was a young grape we were still flying piston engines fueled with AvGas on the COD. The first turbo prop C2s were replacing them. I remember arrival of the first F14s when they came to the fleet and our F4s were sent to the boneyard to be stripped for spare parts for the Shah's air force.
 
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