Bad reloading decision

[cwbuff]

A friend of mine was not getting the accuracy he expected from his rifle. So he decided the bullet needed to be are larger diameter. He is lucky the rifle was not destroyed. In the pic, check out the normal case head on the right vs the "high pressure" case head on the left.
pressure..jpg

[leftyo]

just how much bigger of a bullet did he use?

[randy langford]

I wouldn't think a round with a bullet very much larger than standard would even chamber. Have you personally examined the case in photo and one of his finished rounds, just wondering?

[mold maker]

Something fishy here.

[psteinmayer]

Why do the rims appear to be different size? Higher pressures will certainly bulge a case, but shouldn't increase in rim diameter. I think that photo is suspicious.

[cwbuff]

just how much bigger of a bullet did he use?

The standard bullet is .264, he used a .268. These are long bullets in 6.5mm

[cwbuff]

I wouldn't think a round with a bullet very much larger than standard would even chamber. Have you personally examined the case in photo and one of his finished rounds, just wondering?

I have the case, but don't recall the finished round.

[cwbuff]

Why do the rims appear to be different size? Higher pressures will certainly bulge a case, but shouldn't increase in rim diameter. I think that photo is suspicious.

The photo was done by standing a good and the bad case on my scanner. What you see is how that case was extracted from the rifle.

[joem]

A friend of mine was not getting the accuracy he expected from his rifle. So he decided the bullet needed to be are larger diameter. He is lucky the rifle was not destroyed. In the pic, check out the normal case head on the right vs the "high pressure" case head on the left.
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It looks to me that the high pressure case on the left has clearer head stamps that the right. Is the image reversed as the one on the right looks like the head stamp is somewhat mashed.

[cwbuff]

It looks to me that the high pressure case on the left has clearer head stamps that the right. Is the image reversed as the one on the right looks like the head stamp is somewhat mashed.

The high pressure case is on the right, the normal case is on the left.

[Major Tom]

psteinmayer is right. Looks very suspicious. Case heads do not expand like that.

[Parashooter]

. . . Case heads do not expand like that.

They do when it's good brass, the breech gives solid support, and the excessive pressure is therefore confined in the case.



Case on right is normal, deprimed, .284 Win. formed to 7.5x55. Case on left was the same size until fired with the wrong powder (WC846 instead of WC852), generating estimated 82,000 psi. (Velocity of the 168-grain bullet was 3220 fps on the chronograph I was using - normal is ~2700.) Head expanded uniformly, with smooth K31 bolt face containing gas perfectly despite significant primer pocket expansion. Recoil was stiff but no gas escaped. Quality brass can take a lot of abuse.

The .268" Hornady 160-gr. bullet, designed for the 6.5 Carcano, has a history of pressure anomalies in long-throated barrels, particularly with slow-burning powders, apparently from sticking in the leade before sufficient pressure has built to overcome engraving resistance.

[dave]

Going from .264 to .268 should not raise pressure that much. Germans went from .318 to .323 with no problem, they did not rebore altho they did relieve chamber throat.

[Hefights]

With that much apparent difference in diameter, is the rifle damaged? Can you post a picture of the fired cases standing side by side? Chambers do not grow or stretch that much without a big problem. So perhaps there was a "flow" in the brass somehow but it survived, but the chamber cannot have stretched that much in diameter.

[Matt Anthony]

With that much apparent difference in diameter, is the rifle damaged? Can you post a picture of the fired cases standing side by side? Chambers do not grow or stretch that much without a big problem. So perhaps there was a "flow" in the brass somehow but it survived, but the chamber cannot have stretched that much in diameter.

For someone to use the wrong size bullet, when it's published as plain as day in every reloading manual, is just plain stupid! Yep I said it, STUPID and remember you can't fix stupid. Any time you reload any cartridge, double check your components, measure and weigh each component so there is no chance of making a very costly and stupid mistake that could cause harm to others and yourself.
Matt
Matt