Proof testing 12 ga

[laughingson]

I need some input about proof testing my 12 ga. P.B. shotgun barrel. New breach plugs are in and before proceading further I want to proof the barrels. William Brockway, in his book "recreating the dbl. shotgun", on page 44, recomends using a dbl X dbl load. ie. singel load of powder w/ dbl. loan of shot amd then dbl. load of powder w/ single load of shot. THAT seams to be very hot to me!!! Your thought please.

 

[Walks Alone]

Welcome to the forums.

Seems like I read someplace the standard is a double load of powder with single projectile/shot, but I'd suggest that instead you do some researching at the standards organization C.I.P. as a much safer starting place to confirm what the atandards are for proofing black powder arms barrels/breech instead of trusting my memory.

WA

 

[laughingson]

Thank you Walks Alone for your reply!!! I do not know what C.P.I. stands for. Can you help?

Larry

 

[Walks Alone]

Permanent International Commission for Firearms Testing aka Commission Internationale Permanente (C.I.P.).

Larry

CIP's Link

 

[David W.]

I agree with Walks Alone. Do some research instead of taking someone's word for it. It is probably correct however, that the proof charge is roughly double the maximum service charge.

 

[matt denison]

Brockway's method would simulate a distracted person double charging either powder or shot. It happens in real life. If you are going to go to the trouble of strapping it to a tire and using a string to touch it off then this is as good a method as many others that you will read about. Your gun should be able to handle a double charge or it ain't safe IMHO. You need to know that before it happens by accident. Otherwise, what's the point of proofing it in the first place.

 

[David W.]

Brockway's method would simulate a distracted person double charging either powder or shot. It happens in real life. You need to know that before it happens by accident.......Otherwise, what's the point of proofing it in the first place.

I hate to admit the time I double loaded a barrel of my .58 Kodiak Express. Double loading a barrel is easy, if one doesn't watch what they are doing. I had 280 gr FFg Goex behind a 560 gr Improved Minnie. My shoulder never forgot that episode. It didn't do my unprotected ears any good either.

By all means, when you proof it, use a fuse and stand at a safe distance.

 

[Zonie]

Dixie Gunworks lists the Belgian Proof load for a 12 guage as being 308 grains of powder under a slightly undersize (.024") roundball weighing 493 grains.

Dixie also shows a 1887 muzzleloading provisional proof for the 12 guage as being 350 grains of powder under a 535 load. They don't say if the lead is a ball or shot but I assume it is under a ball.

Neither of these proof loads give the powder granulation but I'm pretty sure it would have been 2Fg powder.

This same 1887 chart gives a definitive Proof load for the 11 guage as 191 grains of powder under a 765 grains (1 3/4 oz) of shot.

If you decide to actually proof your barrel you should have the barrel magnafluxed to see if any hidden cracks were created by the test.
Technically this is called Magnetic Particle inspection.
Many auto engine rebuilding places have magnaflux machines to do the test.

If you can't find a place that does magnaflux then take your barrel to a good gunsmith and have him do a fluorescent penetrant test to see if any surface cracks are present.

 

I studied gunsmithing in the 60's under Bill Prator master barrel maker. P.O. Ackley's head man before he went into teaching. He gave me the honor of working in his barrel making shop located across the alley from the college for barrel buying credit. His rules were simple. Make rifle and pistol barrels with the very finest of steel. Throw away or bore to a larger caliber anything which is not within tight tolerances of the rifle caliber you are making. Grooves and lands must be cut correctly and polished perfectly for the bullets or lead which will be shot down the bore.
When the barrel is mounted to its intended action do not overload the barrel with a charge that could possibly cause excessive pressure and damage the action, set back the bolt face, overstress the breach plug threads, swell the barrel. As, one of these problems may not be seen and cause the rifle, pistol or shotgun to come unglued when some young man is out on an afternoon hunt.

 

[laughingson]

Thank s to all of you for your responce!!!! Any other input will be greatly appreciated. Looks like I have more home work to do before making any blue smoke.

Thanks all
Larry

 

[Dave Rosenthal]

280 grains of powder! OMG! :slap:

The first clue would have been the ramrod would only go halfway in! :haha:

Wish I could have been there to see all of that powder burnin' in mid-air! :shocked2:

Anyway, glad that you & your shoulder are still in one piece!

Dave