Proof Loads

Brimfire

Well-Known Member
An educatory question more than anything. I was wondering what the proof loads were for particular calibres. I am not sure how true this information is, but for a .577 BP muzzle loading rifle the proof load is 192grn of BP pushing a 724grn bullet. I am more than happy with a 70grn load with a lighter bullet.

The real question is there any verifiable data for proof loads? I'm talking mainly for metallic cartridges rather than BP muzzle loaders. It is purely for personal interest as to what kind of charge my firearms have been subjected to in the proof house.
 
Whilst you, now, may not get the exact recipe of powder and charge they are about 65% overload and oiled so as to give maximum back thrust on bolt lugs. IMHO the thing's a make work nonsense in that we don't test new factory fresh crash helmets individually and the charges! An MOT costs what? Walk in, on demand, at the Proof House that's our minimum charge, Sir. Oh...and 50% additional for the on demand!
 
An educatory question more than anything. I was wondering what the proof loads were for particular calibres. I am not sure how true this information is, but for a .577 BP muzzle loading rifle the proof load is 192grn of BP pushing a 724grn bullet. I am more than happy with a 70grn load with a lighter bullet.

The real question is there any verifiable data for proof loads? I'm talking mainly for metallic cartridges rather than BP muzzle loaders. It is purely for personal interest as to what kind of charge my firearms have been subjected to in the proof house.

I was looking into rebarreling my 223 into 6x45 and phoned up Birmingham Proof House to see whether they held proof rounds for that caliber. They said that they did not, but would proof it provided they were provided with 3 rounds that had 10% more powder than the maximum charge that was likely to be used in the rifle.
 
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Proper CIP (of which we are a member) proof loads are 25% higher pressure.

I do agree with Enfield though. The US has no proof procedure and it's not a problem. If they ever do have problems it can always be traced back to cheap foreign arms or over hot handloads
 
I was under the impression that a proof load was 125% of max pressure ,it is pressure not powder that is measured although the two are obviously linked .
 
I was under the impression that a proof load was 125% of max pressure ,it is pressure not powder that is measured although the two are obviously linked .
Pressure is the standard. Calling simply for 10% more powder is ludicrous. The difference is that in the UK you proof the weapons. SAAMI just proofs the integrity of the case and loads, setting standards for it's production. Safety of the weapon for factory cartridges is assumed by the manufacturer. ~Muir
 
So what happens in the case of wildcats? Do they just do a half arsed job and stamp it with proof marks anyway?
This illustrates the fallacy of 'proofing' as you guys know it. You can't proof a wildcat. If they indeed asked for a 10% overload of powder, and the round already uses a compressed charge of Powder X, what is the recourse? Many on this site have claimed proofing is a rip off. I tend to agree.~Muir
 
There was an instance of the London proof house where they stamped .22cf mods with the .30 cal stamp. Bit of a cockup as the hole was smaller than .30.
 
originally with Black Powder the proof house used a special blend of black powder according to the history I read. But no it is a farce it seems. Was reading about teh 280 AI and they just asked the chap for three formed cases then the proof marking were so faintly etched than with the finishing for bluing they were almost removed. The photos and build info were posted ona gunsmithing forum:....

http://curioandrelicfirearmsforum.y...ject-280-AI-Picture-heavy-Part-1#.V0goR_krK00

http://curioandrelicfirearmsforum.y...ly-blacked-my-280-AI-BSA-Monarch#.V0gnuPkrK00

I thought I had seen these photos on this forum but have been unable to locate them a google search for builds nad projects threw this one up.
 
Pressure is the standard. Calling simply for 10% more powder is ludicrous. The difference is that in the UK you proof the weapons. SAAMI just proofs the integrity of the case and loads, setting standards for it's production. Safety of the weapon for factory cartridges is assumed by the manufacturer. ~Muir

Surely there is a certain amount of fallibility around proofing if you look at pistol calibres with fast burning powder. Assume someone accidentally throws a double charge of their chosen pistol powder into a pistol calibre case and then pulls the trigger. Not sure I would want to be standing next to them.
 
Yes. A double charge of, as then know, Hercules's Bullseye was fairly fatal for some handguns.

A double charge of fast pistol powder was also fatal for a genuine Remington Rolling Block as well. Blew the action apart and if the reports that came back to the clubs committee were correct injured another shooter on the line. Our club was heavily into historic arms and although it was no one connected to our club the incident was mentioned to them to pass on the caution of inappropriate powder choice and lack of care when loading.
 
Yes. A double charge of, as then know, Hercules's Bullseye was fairly fatal for some handguns.


The process even had a name. I was once shown a (previously) very nice S&W 686 with a shattered cylinder, a bent down barrel and a very bowed top strap. It had been "bullseyed".
 
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