Anyone running 180 Bergers over 3100 fps?

[chuckhammer]

Same seating depth (jump)?

That's scary for what should be such a minor change.

 

[Rent Outdoor Gear]

That's SCARY man! That sort of thing can happen when you're loading to the max plus with temperature changes and a new lot of powder. If it over-pressured your chamber enough to change the headspacing, I'm not sure I'd be comfortable shooting that barrel anymore - not at least at the velocities you were pushing out of it. If it moved the shoulder, what else changed?

 

[idaho elk hunter]

I will tell you this. As long as I have been doing this I have loaded over conservative book loads that are downloaded to very safe levels.

I was OVER book. My barrel is a Broughton 5c 1 in 9 twist. Coal is 3.5 inches the bullet .015 off the lands. Coated with Hex Boron.

The previous original safe loads that were the same loads were somewhat hot. To give a idea of my determination of a "safe" level. They were loaded 4 times loaded was the life span of the brass. Expansion in front of the belt was .02. Primer was starting to flatten but not flat by any means. Loaded to extractor mark was faint on the case head and backed off 2 grains.

All I can think of is some off the Glycerin on the opened can evaporated out in storage causing a burn rate so different than an sealed can. Has anyone else had this experience?

 

[chuckhammer]

If the headspace increased due to overpressure, I'd bet it's the bolt lugs setting back into the receiver rather than the barrel shoulder yielding.

 

[Rent Outdoor Gear]

If the headspace increased due to overpressure, I'd bet it's the bolt lugs setting back into the receiver rather than the barrel shoulder yielding.

Yes, that makes more sense - much easier to put a dent in the lugs or bearing surface than yield the chamber. Might want to inspect the bolt closely. Sheared bolt lugs is a very ugly failure.

 

[Lefty7mmstw]

I posted earlier on the velocities of my 7mm Rem pushing velocities higher than the STW. I even verified the velocities through a Magento3 and a Pact. Something interesting happened last week. Getting low on loaded ammo I loaded some more up. Same powder, Same WW cases. same primer, Same lot numbers. The only thing different was the powder was a unopened keg. The very first shot blew the primer, Bolt was so still I had to take a rubber mallet to it. WOW. I have never had this happen before.

Keep in mind the powder, primers, cases were all bought on the same day at the same time and are all the same lot numbers.

Outside Temperatures were within 15 degrees of each of the days shot.

The only difference was the powder keg was never opened making it "fresh"?

I have had this with different lot numbers and hotter days. But even then It did not over pressure this much.

To let everyone know of how much over pressure it was I have to reset my headspacing. Scary overpressure.

Needless to say I am backing my loads down to 3000fps in the 7mm Mag.

I'm glad you didn't blow anything off of yourself. It takes gumption to admit you've screwed up.

Come on over to the dark side and punch her out to 7stw. Then you can run 3100 fps with your 180's with ease if you've got slow enough powder. h&h brass is available to blow out and you can buy Nosler if you feel rich.

As to your powder, you may have also added weight via humidity and actually been shooting a bit lighter charge than you thought you were. I doubt you lost more than a bit of nitro, but even a bit could have also helped you along also.

People speaking of book loads being mild has always scared me a bit. I've blown primers on an occasion or two with book loads. All it takes is the stars to align a bit out of your favor and you not being quite careful enough to cause bad things to happen.