Something stupid

[chomondely]

Ok, after 40 years of reloading, I used the wrong powder. I grabbed the wrong bottle off the shelf and I did not double check it as I usually do before I put it in the powder measure.

This error did speed up the reloading process as the primer fell out of the case after I pried the bolt open. No need for a primer press as a new primer fell into the primer pocket. No need for even finger pressure. It is bit awkward to keep the bullet pointed down or else the primer will fall out of the pocket.
I put 68 gr of Varget behind a 140 gr bullet in a 7WSM instead of 68 gr of IMR 7828. Sierra only recommends 55.7 gr of Varget.
After I realized my error, I checked the bottle of IMR 7828. I discovered that I had poured the powder remaining in the measure back into the IMR 7828 bottle. The polluted bottle is now in the trash.

Can anyone use a computer program to tell me the chamber pressure and the velocity? Or is it so high that I don't want to know?

 

[222Rem]

I don't want to know chamber pressure. What I want know how you survived it to ask this question?

 

[7stwhunter]

what was the seating depth and what bullet??

 

[GermanS1]

Well over 90,000 psi from your description of the case, maybe more. The important thing at this point isn't to estimate the pressure, but to examine the rifle. Have the headspace checked to make sure the lugs didn't set back and give the lugs themselves a detailed visual inspection. Magnafluxing for cracks would be prudent too.

 

[Forum Boss]

Glad to hear you're OK. I'll defer to German who has pressure testing equipment, but a rough,very rough) estimate from Quickload,since I don't have details of seating depth, bullet specs) is that you were at 95,000 + psi. That assumes a Sierra 140gr SP and a 2.820 COAL. Hodgdon Varget data says 98K psi, while ADI 2208 data says 94.3K psi. Your lot of Varget is probably somewhere in the middle.

I cringe somewhat at the potential harm that can occur if powders get misidentified or put in the wrong bottles. My practice is to put the factory powder bottle right on the bench next to the measure.

 

[chomondely]

Winchester M70 with Krieger barrel. I'm glad that Winchester builds a strong action. Gunsmith checked and he said it was OK. He was not impressed with my attempt at load development.

After the shot, lots of smoke coming from more places around the bolt than I thought possible. The case ejected. Now that I know what happened, I'm surprised that the case head did not separate. Bullet impacted 2 inches high at 100 yds. Glad I was wearing safety glasses. No impact of gas on my face. It seemed a bit loud even though I was wearing hearing protection.

Rifle still shoots .3 at 100 yds with the correct powder,
140 gr Sierra SP, .01 off the lands, Federal Magnum primer.
The lands are still in the barrel.

I too always,I thought) put the factory bottle next to the measure. I never relabel the bottle. Thank goodness that Varget looks different from IMR 7828. I would have tossed the contaminated bottle any way. It was nice to confirm that I was the one who had contaminated the powder and that not a mistake from the factory. Very humbling to look at the powder, see that there are two different types of powder mixed together and realize that you are the cause.

What is the pressure of a factory proof load?