Proof Marks

[ovenpaa]

Ever followed an Audi A4 driver? They are usually 'Proof driving' their company car

[Rockhopper]

Samples of new ones are though and the MOT system tries to ensure that each car on the road maintains that level of safety (in terms of structural integrity etc).

[dromia]

Yes samples of new cars are tested but not every car, as you are supposed to do with firearms.

The MOT is not a test that subjects the car to events that it is not supposed to perform at, and like the proof test all it means is that it passed the test it is no guarantee of safety.

[Chuck]

[mullen7]

It's honestly f*** stupid. Lets fire a heavy load through your barrel. Oh it never broke. GREAT it's proofed. But you've just taken that barrel to a pressure that it never will see. And have possibly caused weaknesses in it, wouldn't have showed during the proof obviously if it passes. But I can bet my bottom dollar that it is not good for the barrel. I'm pretty sure there's a better way of doing it using NDT but our country is backwards.

[FredB]

i worked in design and development in the motor industry for 40 years. Proof testing is not equivalent to an MOT. It is similar to what we did to prototypes of safety critical parts before issuing drawings and specifications to production. After these tests, the prototype parts were scrap. Service failures are virtually always a result of metal fatigue and overload testing reduces the fatigue life of a highly stressed part dramatically.
Fred

[saddler]

Group Buy maybe?
Take over the Manchester Proof House & re-open it?

[ovenpaa]

Fred, were you working for a Tier 1 supplier by any chance?

[WelshShooter]

Proofing doesn't make sense to do on every modern firearm as there's always a chance of weakening the receiver because you are inducing forces that were never set in the design. Why can't this be done based on a sampling rate with batch processes (i.e. If you make 50 barrels in one batch why not destructive test first on /last off?). It's the same principle as special processes in manufacturing where you cannot measure the part without destroying it (a la crash testing in automotive).

[redcat]

I think you will find that batch testing is exactly what happens, in the Italian proof house at least. I visited there in 2005 and watched a double barrel shotgun go through test. The gun was broken down and all areas of the barrels and receiver were measured. The gun was reassembled and test fired. It was then broken down again and the parts were visibly inspected and measured to see if any "stretching" had occurred. From the point of view of the time taken it would not be physically possible to do all of the shotguns that came in, let alone the thousands of other arms. Imagine how long it would take to load and test fire every percussion revolver from Uberti and Pietta!

Redcat