Proof Firing

[Bill Ricca]

You have heard the terms "Proofed" or "Proof Fired". These terms indicate the item passed a test procedure. This applies to all US GI firearms.

Each Barrel, Bolt, and assembled rifle/carbine/machine gun is fired with a High Pressure Test Round, also known as a Proof Round. The cartridge has much higher pressure than service ammunition. In the postwar period afterwards the barrel or bolt would be "magafluxed, or magnetic particle tested", to check for cracks.

After firing the Bolt, Barrel, Receiver and in the case of an assembled rifle, the stock, are all marked as an indication of passing the high pressure test.

The marks are as follows:

Stock: P in a circle or square
Bolt: PR!CK punch mark and some can have an M either inscribed in electric pencil (M14, M16) or white paint stamped on the body (Carbine) indicating it was magnetic particle tested.
Receiver: PR!CK Punch Mark
Barrel: P for Proofed, M for Magnafluxed or Magnetic Particle Tested

Do not be surprised if occasionally you see a barrel with two P's or a bolt with two punch marks. If a barrel was destined to be a spare part, it was proofed. Later on if it needed for assembly into a rifle, it was proofed again as a rifle. Sometimes two marks will be present, but not always. Occasionally on a Garand bolt you will see two punch marks, as it went through rebuild and both times it was marked.

Here is a picture of the M1 Carbine being proof fired. Notice the protective cradle. The weapons are fired remotely because occasionally one will detonate due to structural failure. The right side shows a stripped barrel being proof fired.




---------- Post added at 10:16 AM ---------- Previous post was at 10:14 AM ----------

Part II:

As shown above this applies to all US GI weapons. Here are the specifics for the M1 and M14. It is described in detail in some NM publications.







On many message boards the actual designation of the military punch mark is a word that cannot be used. In some areas it is a "bad term", thus the spelling on all message boards is PR!CK PUNCH. The actually military designation will get the word deleted or hidden from view.

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