How did the Armories "Proof" a barrel before modern methods?

O

Old Time Hunter

New member
The thread on "Best WWI Rifles" migrated to strength and hence, pressure. AMP 44 gave a pretty good description of how the CUP (Copper Units Pressure) pressures were derived and most are familiar with PSI testing methods. But how did the Springfield Armory "proof" the barrels or chambers of the Trapdoor? How did the British or German gun manufacturers "proof" the barrels back in the 1800's, the 1700's, or even as far back as the 1600's?

Did they just keep loading powder in it until it exploded? 'Suppose serfs were cheap...
 
L

LukeA

New member
IIRC in the early days (1600s) they proofed guns by firing them with an extremely large powder charge, like a double or triple charge. The gun passed if it survived without a kaboom.
 
K

kraigwy

New member
Find a copy of Hatcher's Notebook, MG J. Hatcher. He covers that quite well, way more in-dept to go into hear. But yes, high pressure proof loads were used.

Besides no serious shooter should be without Hatcher's Notebook.
 
4

44 AMP

Staff
Proof Houses

Nations with their own small arms industries had "proof houses", a department that "proofed" guns by firing them with "proof loads" These are specially overloaded cartridges, giving much higher pressures than regular ammo.

If the gun survived firing a certain number of proof rounds (and I don't know how many, certainly one, for each chamber, I would assume), it was passed, and stamped with a proof mark. England required all imported guns to be proof tested by their own proof house, at one time. I don't know what they do today, but I expect not much as they don't import many guns anymore.

For example, US GI proof rounds in 7.62mm Nato and .30-06 are listed at 67,500psi, where the regular ball ammo is 52,000psi. 5.56mm is 70,000psi proof, M193ball is 52,000psi. And .45acp proof is 22,000psi where ball ammo is 19,000psi - info from Cartridges of the World, 3rd Ed. Barnes/Amber.
 
L

LaserSpot

New member
Seems like a good idea, I wish they still did this.

In the case of pistols with one or more barrels, the proof firing of which in accordance with Paragraph 3 and 4 is not possible, the proof charge shall be determined, taking into account the length of the barrel(s), according to the maximum service charge laid down for that type of firearm. The quantity of proof powder must be twice the service charge.

http://randywakeman.com/bpcip.pdf
Click to expand...
 
M

mapsjanhere

New member
That is a reason why a lot of guns have a series of proof marks. It started out with a first barrel white finish proof with regular load, followed by up to three loads with up to 50% overpressure, depending on country.
Proofing in 19th century England must have been fun so, the standard method used round ball and 4 times the usual powder amount.
 
F

FrankenMauser

New member
Anyone that owns a Mosin Nagant rifle should be able to find a minimum of two chamber proof marks, with a possibility of up to five (plus 2-4 for point of impact and accuracy - it all depends on the model and year).

All MNs started with a black powder proof firing. (Some had a "provisionary" firing with just a raw barrel clamped in a firing fixture, before the first black powder firing in the barreled action.)

The final chamber proofing was an over-load of smokeless powder, and often consisted of three cartridges being fired (again, the actual number depends on the year).

After chamber proofing, standard ammo was used to tune the point of impact, and certify the rifle capable of minute-of-bulldozer accuracy. This could include up to 4 different steps and stamps for standard rifles. Interestingly, and counter-intuitively; special rifles destined for certain special units often received fewer proofs than regular rifles, rather than more proofs.

Oh, and if the rifle was designed to accept, or had a built-in, bayonet, they were attached or extended for all of these proofing and accuracy tests.
 
You must log in or register to reply here.
Top