Case forming question??

[rockhound78]

Made a 6mmX out of a 243 barrel I had on the shelf and have been working on loads for it. I am using re-formed 22-250 brass. Have a couple of different decent loads for the 70 and 80 gr Nos. BT.
Now, when I want to re-form some more brass, can I just use the loads I have developed with previously formed brass, or do I need to reduce the load? Will the brass form itself to the chamber as pressure is rising so pressure will not be too excessive, or will the pressure rise so fast that the brass will not have time to re-form itself before max. pressure?

 

[mikecr]

Hard to say. Brass expansion does consume some energy, while a higher load density can still raise pressure. Could be a wash.
I would not be afraid to fire form with a chosen good load.

 

[Ray B]

I'm not familiar with the cartridge, but it appears the question is: can you use a full charge in a case that is smaller than the chamber so that it will fireform to the larger size? This process is exactly what happens when standard cartridges are fired in improved chambers. For example full power 300 H&H cartridges are fired in a 300 Weatherby chamber, resulting in slightly less velocity than if the cartridge were fired in an H&H chamber, but yielding a perfectly formed Weatherby case.

 

[fguffey]

Will the brass form itself to the chamber as pressure is rising so pressure will not be too excessive, or will the pressure rise so fast that the brass will not have time to re-form itself before max. pressure?

as pressure is rising so pressure will not be too excessive,

I believe it is a bad habit but many reloaders use pistol powder when fire forming. I don't. I understand when fire forming I am forgiven for what most reloaders believe is a mistake. I am forgiven because of time, and then there is the bullet; I do not like the ideal of having the bullet setting against the rifling. Reloadrs five no consideration to the difficulty the bullet can have getting past the rifling meaning I am the fan of the running start, I want my bullets to have 'that jump'. When the bullet hits the rifling I want the bullet past the rifling before the knows it is there.; as opposed to forcing the bullet to be pushed thorough the rifling from a dead stop.

Time is a factor, I have fire formed cases with loads that exceeded maximum loads, the load did not become over maximum until the case was formed meaning I had to back the load off by 5 grains and start over or reduce the weight of the bullet by 50 grains.

F. Guffey

 

[alinwa]

I believe it is a bad habit but many reloaders use pistol powder when fire forming. I don't. I understand when fire forming I am forgiven for what most reloaders believe is a mistake. I am forgiven because of time, and then there is the bullet; I do not like the ideal of having the bullet setting against the rifling. Reloadrs five no consideration to the difficulty the bullet can have getting past the rifling meaning I am the fan of the running start, I want my bullets to have 'that jump'. When the bullet hits the rifling I want the bullet past the rifling before the knows it is there.; as opposed to forcing the bullet to be pushed thorough the rifling from a dead stop.

Time is a factor, I have fire formed cases with loads that exceeded maximum loads, the load did not become over maximum until the case was formed meaning I had to back the load off by 5 grains and start over or reduce the weight of the bullet by 50 grains.

F. Guffey

please put down the bottle and back away from the keyboard..........slowly now.......

For The Love Of GOD people don't lissen to this stuff!

I agree with mikecr, I wouldn't be afraid to use a known load and HAVE done..... OTOH....When one "has to back off 5 grains or 50 grains" one should NEVER BE THERE with a first round.

And 5gr or 50gr mean entirely different things when referring to a 22-250 VS a 300WM....... to the beginning reloader some of the niceties may be vague and posting broad generalities can be dangerous. Especially when posted by "the best reloader ....In The WOOr'ld" A man who purports to be the only guy on the planet "who truly understands reloading"

fguffey you need to take responsibility for the fact that someone, somewhere might LISSEN to you!

Be safe out there people, use the reloading manual recommendations until you've a deep understanding of the processes involved and like yer Momma said, "don't take candy from strangers"