Real Gunbroker Men of Genius

U.S. Military Krags
Griff557
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Re: Real Gunbroker Men of Genius

Post by Griff557 » Thu Mar 26, 2020 9:56 pm

No horse in the race-not defending anyone or trying to start something but its possible the 303 case was a hand load resized to 30/40

Baltimoreed
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Re: Real Gunbroker Men of Genius

Post by Baltimoreed » Thu Mar 26, 2020 11:10 pm

I made some emergency ration [during the brass shortage] .303s into .30-40s for my Krag scout rifle. Shot fine but I didnt try any real .303 loads in it.

FredC
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Re: Real Gunbroker Men of Genius

Post by FredC » Thu Mar 26, 2020 11:32 pm

I made some emergency ration [during the brass shortage] .303s into .30-40s for my scout rifle. Shot fine but I didnt try any real .303 loads in it.


I am going to go out on a limb and guess that you are not a risk taker. Using 303 brass for reloading with sane Krag loads - no risk.

Putting a higher pressure 303 round through a .308 diameter barrel is very risky. Maybe the guy has one of the early barrels that was really .311, but he is still living on borrowed time, on a hot day with 49K PSI the pressures could really get out of hand. If he has done a lot of this insanity he may have set the locking lugs back and have greatly increased his head space.

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psteinmayer
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Re: Real Gunbroker Men of Genius

Post by psteinmayer » Fri Mar 27, 2020 12:22 am

While shooting the .303 in a Krag is probably not wise... the likelihood of shearing off the locking lug and sending the bolt into the shooter's face is doubtful (I refer to the late Michael Petrov's experiments).  Now cracking the lug, receiver or both is more likely, I suspect it would hold up longer than people think.  Again, refering to Petrov... he used a case full of Bullseye before he finally destroyed his Krag, and this was after shooting several loads that far exceeded the recommended max 40,000 CUP.

Rcat7147
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Re: Real Gunbroker Men of Genius

Post by Rcat7147 » Fri Mar 27, 2020 12:49 am

These old guns are much stronger than theyre given credit for.
Referring to Mr. Petrov again, apparently the Trapdoor took so much abuse before detonating he would never publish the data!!  Sure would love to see those numbers just for scientific curiosity.

Whig
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Re: Real Gunbroker Men of Genius

Post by Whig » Fri Mar 27, 2020 1:17 am

The proof mark on Krag barrels supposedly showed that after production testing was done successfully with a load rated at 70,000 psi. PSI and CUP ratings are somewhere around 7% of each other, + or -.

So, the "safe" rating of 40,000 CUP does not mean that things start blowing a part at 40,001 CUP. There's some room to spare, Mr. Petrov's experiments not to be ignored, though.

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Culpeper
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Re: Real Gunbroker Men of Genius

Post by Culpeper » Fri Mar 27, 2020 6:16 am

But. ...But. ...But what about 40,000.25? The Horror! That's it. I have the answer to safely handle my Krags. I'll put together some deer hunting rounds using spent primers.

Whew. Now I will not have to worry if 112 will blow up on me while I am hunting. ::)

I agree. Some folks (no one here) forget that the gun designers in the late 1800s were accomplished and talented engineers who would never put their names on an inferior and dangerous gun that could cause harm to people.

.
Deacon in the Church of the Mighty Krag. Member of People Eating Tasty Animals (PETA).  [url=https://radio.securenetsystems.net/v5/index.cfm?stationCallSign=LWRN]Liberty Works Radio[/url]

FredC
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Re: Real Gunbroker Men of Genius

Post by FredC » Fri Mar 27, 2020 2:29 pm

I have been hanging around here long enough to know the Krag is relatively strong and long lived if common sense is used.
I got the impression the seller had been feeding hundreds of rounds of 303 through it. Finally looked at the ad and 3 rounds. He bought it from someone that thought is was converted. Maybe he is just an idiot for goofy advertising, instead.

I have never touched a drill to a Krag receiver, but it has been described by a gunsmith that I trust as hard on the case and butter soft under the case. Looked at the fellows gauging of the barrel with a 303 round, I would guess that barrel is closer to. 308 than . 311 or .313. All that said if 303 rounds are loaded to 49K Cup then this thing has operating at 30.06 pressure levels for some time. Butter soft steel will move under abuse even though no cracks show. I think this would happen mainly in the receiver as the bolt treated with cyanide on the lug would be harder since more surface area on the angles and corners would have been benefited from the extra carbon.

My worry was that increased head space could lead to a separation in the extractor area. Looked at a loose Krag barrel and that is pretty unlikely. If the headspace is stretched on this one, a person could keep on using 303 brass with 308 bullets and stop further damage. It is a shame this was done to an otherwise nice looking rifle. Maybe the first owner that did the 303 thing, only shot a few rounds and damage is minimal to non-existent. I would pass on it because of the unknown.

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Parashooter
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Re: Real Gunbroker Men of Genius

Post by Parashooter » Fri Mar 27, 2020 5:23 pm

. . . if 303 rounds are loaded to 49K Cup then this thing has operating at 30.06 pressure levels for some time. . .

This topic demonstrates the level of confusion arising from old and newer pressure methods. By current SAAMI standards Maximum Average Pressure (MAP) for .303 British is 49000 psi measured by piezo transducer and 45000 CUP by the old copper crusher method. These pressures are actually the same - it's only the method that's different. Old publications from before general adoption of piezo equipment usually express crusher pressures as "psi", leading to many misunderstandings.

The latest SAAMI publication I have doesn't list a transducer pressure for the .30/40 cartridge (probably due to low production) but specifies a MAP of 40000 CUP (crusher). While the difference between this pressure and the .303's 45000 CUP is substantial, it's not what I'd call catastrophic. In addition, the .303 cartridge shown in the auction is likely Winchester commercial 180-grain - not necessarily loaded to maximum pressure.

Table below comes from an old Hercules data booklet -

Whig
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Re: Real Gunbroker Men of Genius

Post by Whig » Fri Mar 27, 2020 5:54 pm

This is the same kind of tabulation that shows there is a + or - 7% variation between these two pressure unit determinations.

Good discussion about concerns for over-pressurizations and re-loading concerns with these older firearms.

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