doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Some English guns won't make proof.

External striking up and polishing, especially in pitted barrels, removes more metal than internal honing, in my experience.

Internal honing on modern machinery is precision controlled. External filing and polishing is not.

It is possible to have in proof shotguns with pristine bores, well within the proof max of 0.789 (18.9mm) yet thinned by external polishing.

The Belgian system that recorded the weight of the barrels, and made reproof obligatory if there was loss of more than 3 per cent weight had its merits.

I suppose it might be a part of initial manufacture, but if no one trusts proof stampings after that point, what's their value?

Craig, the value is that in their countries of origin, the gun is supposed to be submitted for reproof and those proof stampings changed if there's been significant modification to the gun in question: Chambers lengthened, barrels honed so that they're maybe .010 or more larger than originally stamped, etc. So the value is, with bore and choke and chamber gauges, you can very quickly determine how much the gun has been tampered with since it was originally proofed. Or reproofed.

Shotgunlover,

Thanks for that bit of information on Belgian proof. If that was combined w/British proof law one would have a very good proof law that addresses both internal & external modifications to the bbls from the original condition that they were in when proofed.

Well, depending on country where proof was done they help identify county of origin chamber length and weight plus power of loads the gun was originally designed for. Being we have "tire, string, big tree" as proof house in America we can go by original mechanical condition and measure of barrel wall thickness. I would say they will try to sell you anything in USA safe or not so be aware what you're looking at.

Sorry, I have been a while replying to this, but I had a word with a very important person and he pointed out that the various Proof Laws forbid unscrupulous people from circumnavigating safety issues . But it should be possible for you gentlemen to obtain SAAMI Proof loads to self test any guns that you have concerns about.
British Proof specifications factor in the safety factor for reasonable age and wear, if it is out of proof it just is not safe.

Nobody seems willing to state the obvious on this, so I will.

"But it should be possible for you gentlemen to obtain SAAMI Proof loads to self test any guns that you have concerns about."

That is poor advice.

SAAMI proof loads are only available to those who have any business applying them, namely manufacturers of new guns and other SAAMI affiliates.

There is more to the business of British Proof than simply firing the cartridges.

Anyone capable of doing the required pre-proof firing inspection is well capable of determining the safety status of a gun without setting off 20K psi bombs in it.

'Out of proof' is a technical term, and not necessarily indicative of an unsafe gun and certainly no reason for destroying one or putting 20 years of stress on it.

Thankfully, we don't have legal issues with proof here.

Hear, hear, Shotgunjones. Well said!

"in proof" only refers to the interior dimensions of the barrel. I know of no proof test that measures the wall thickness or outer dimension of a barrel other than the actual firing of the gun. If a gun has the original bore dimensions, it is assumed to be "in proof", regardless of how much the exterior of the barrels have been struck. Absolutely crazy.

If Shotgun lovers post on Proof in Belgium re. bbls. weighing <3% of the weight @ original proof being out of proof is correct, that proof law would make good sense & protect the buyer from most (but not all) internal & external bbl. modifications & or repairs.

If nothing else, a step in the right direction.

I've never paid a lot of attention to proof laws other than English so there may be much better proof laws out there to protect the consumer from unscrupulous sellers.

It does seem to me that requiring a minimum wall thickness would be desirable & alterations to forcing cones or chamber length should require reproof as the English proof law does.