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.

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[Bob Seijas]

Just to dot the i, every M1 barrel was proof fired separately after completion, and the letter P was stamped on it to denote that. When it was assembled to a rifle and the rifle was proof fired, a punch mark was to be put in the loop of the P as evidence. In early production this was done carefully as shown, but as production ramped up, the original P became smaller and the punch was hurriedly stamped only in the general vicinity of it.

[bulldog_mack13]

Heres a barrel picture I have put up before. I have heard time and time again this was a replacement barrel for the rifle during the war from a unit armorer , not a sent home and re done rifle. It has 2 P's on it.

[RCS]

Stock in photo has the early second firing proof with a non serif P in circle. The cartouche has been obliterated and the stock is for the solid buttplateAttachment 20272Attachment 20273

[Ramboueille]

Heres a barrel picture I have put up before. I have heard time and time again this was a replacement barrel for the rifle during the war from a unit armorer , not a sent home and re done rifle. It has 2 P's on it.

It has no maker's name on it (SA) and the date is hand-stamped indicating it's a probable forgery. What's marked under the hand guard on the top of the barrel?

[rayg]

Great info Bill. Clears up a lot of questions for me, Ray

[Bill Ricca]

Thanks to Mr. Seijas for the added information. His knowledge is incredible.

[ulflyer]

How about three P's? My 34760** has on the barrel a punch/more like a small dash, then a "P", an U/I mark then way forward another squarish "P" with punch in the loop with a tiny 3 on top left side of that loop, then A 2 45, then where the barrel taper begins, another small "p'' a punch mark near it . Coloration of metal matches and appears original, not reparked.

Sorry, don't know how to post pics. Will try to take some today and can forward to someone by email if desired.

[Bodyman]

Heres a barrel picture I have put up before. I have heard time and time again this was a replacement barrel for the rifle during the war from a unit armorer , not a sent home and re done rifle. It has 2 P's on it.

That is unlike any barrel markings that I have ever seen, ... not sure what ot make of it, other than to say that I don't think it looks real and might be a modern barrel that has had some WWII markings applied. Are there any other markings on it under the handguard?

Oop, just saw Ramboueille's post - I appear to be restating what he is thinking.

[Joe W]

Just to dot the i, every M1 barrel was proof fired separately after completion, and the letter P was stamped on it to denote that. When it was assembled to a rifle and the rifle was proof fired, a punch mark was to be put in the loop of the P as evidence. In early production this was done carefully as shown, but as production ramped up, the original P became smaller and the punch was hurriedly stamped only in the general vicinity of it.

I Know that NM rifles have a 2nd proof P placed on the barrel when the rifle is proof fired as a NM rifle but way do some late Post war SA rifles also contain 2 "P" proof marks plus a punch mark ?? My 5.8, that I bought at the GCA convention in Anniston, has 2 "P" proofs and the punch and I have seen pictures of others. My rifle appeared almost unused.