Almost had a big oops

[bullseye308]

I was teaching someone to reload and double checking everything for them at each stage as they completed it. Found a double charge in a case in the loading block and was wondering what the ballistics and the amount of damage would have been if it had gotten loaded. The round in question is a 357 supposedly loaded over 5.0gr Bullseye & a CCI 500 shooting a 158 SWC cast from WW's. The double charge of course made it 10.0 grains. OAL is 1.59 with a good crimp. Also these were to be fired from a Ruger GP-100 6" stainless if that matters.

TIA

 

[rcmodel]

10.0 grains of Bullseye would be about 3.0 grains over a max load shown in the Lyman #49 manual with a 158 grain cast bullet.

I don't know what the ballistics would have been, but pressure would certainly have been well over anything intended for a .357 revolver.

Whether the Ruger would have been damaged is hard to say.
But I for one, would not have wanted to be holding onto it.

rc

 

[gun guy]

They actually tried to blow up some cheapo pistols in an attempt to determine what a saturday night special was. They weren't able to come to any good conclusions. By the time the pressure was enough to cause the cheaper weapons to fail, to quality "control" guns were failing too. The full power blank load/foul bore accident that killed Brandon Lee must have sent chamber pressures on that model 29 into the stratosphere. Odds are the Ruger would have held together, though might have had some damage. That same load in a lighter 38 special could have been very hazardous. Like they say: "Don't try this at home kids."

 

[RidgwayCO]

Using your data, QuickLOAD predicts a pressure over 71,000 psi, or more than double the SAAMI max average pressure. Assuming the Ruger held together (a very optimistic assumption), the program also predicts a muzzle velocity of over 1600 fps, with over 930 ft-lbs of energy.

Good catch on the powder charging error...

 

[rhoggman]

nice ballistics. I'll back off 10%, and work up a load from there.

 

[Doug b]

Had a friend double charge a S&W M29 years ago with bullseye.It cracked the cylinder and broke his wrist.Good catch.

 

[bullseye308]

Thanks for the replies. Definitely glad to have caught that one. Just a good reminder to use loading blocks and a flashlight to check in every case. Even if you have been doing this for a while, but especially if you are teaching someone new.

What is bad is you can almost get 3 charges in one case, so you really have to be careful. Bullseye is a great powder, but you really have to respect it.

 

[bullseye308]

program also predicts a muzzle velocity of over 1600 fps, with over 930 ft-lbs of energy

I would thought it to be more, but I understand the increase is not linear. but still, only 1600 FPS

 

[qajaq59]

Your student will probably never load without double checking, so it served a good purpose. And it's a good habit to have. Especially after you've loaded for a lot of years and start to get complacent.