Forming 7mm BR from 6mm BR Brass

[kschilling]

Hello everyone... I already posted this topic on another area of this forum.... then I saw the Reloading Forum.

My challenge is forming 7mm BR Brass from 6mm BR Brass. Can it be done and is it safe? My current stock of 7mm BR Brass,RP) is not what I expected and I have access to some 6mm BR Lapua at a great price.

Is there an expander I need to use or is it simple fire forming? I know this sounds like alot of work, but I'm a retired Army guy with nothing to do.... )))))

Thanks.

 

[janderson0]

I've done this with very good results. Just used a K&M expander, and imperial lube. The Lapua brass necks ended up thicker than the 7br Ren brass I have. ,fit better for my chamber) I also found that the Lapua has less run out made from 6br brass than the factory Rem 7br brass.

Jim

 

[Preacher]

Necking up is not a problem at all, but they should be opened up in steps... .041 is a lot to do in one step.. A .257 and a .270, then a .284 mandrel is what I would use to do it.... along with lots of Imperial Sizing die wax.....

 

[olympian]

I go from 6mm to 7mm without any problems using Redding expander and plenty of Imperial Wax. You can do the same from .224 to 7mm as well.....at least making 7mmTCU.

 

[Pem_Tech]

Just tried resizing .243 (6mm) brass to 7mm in a 7mm BR sizer die. Seems to work fine. Will mic it shortly.
Started on a 7mm Mag die, but that produced uneven necks and some had neck bulges. Running the 7mm Mag pre-sized and unsized .243 brass through a 7mm BR die cleaned up the the necks and produced excellent looking product. Dependent on a pending deal I will either have plated 7mm BR brass or will place an order for Norma 6mm BR cases.

 

[A Marsh]

I just made some 30 br brass. I went from 6mm to 7mm in the first step with a K&M expander. Not bad at all.

 

[JayHHI6818]

Not the same but I had no issues necking
7 BR cases to 338 using imperial lube and running them into 338 Whisper sizing die with eliptical button.

 

[Dusty Stevens]

Half full case of bullseye keeping it pointed to the sky will form them. No filler only toilet paper if you need to point it anywhere but up. Bump them back for a crush fit of 3-4 thou

 

[butchlambert]

Or a healthier does of Bullseye with a wax plug to fireform. Makes a better case that expanding them with an expandiron.

 

[NorCalMikie]

I go from 6 MM BR to my 6.8 BR Wildcat in one pass with a Sinclair Expander Mandrel. No issues. First firing will iron out any kinks if there is any.

 

[sean68]

I go from 6br to 30br in one pass with a PMA 6mm to 30 carbide expander mandrel.

 

[jimmymac]

Or a healthier does of Bullseye with a wax plug to fireform. Makes a better case that expanding them with an expandiron.

Hey Butch. Would you do the same going from 6BR TO 30BR? I’m about to head in to uncharted waters with this 30BR thing. Was thinking expandirons in two or three steps to get from .243 to .308.

 

[NorCalMikie]

From experience: Be careful about annealing BEFORE you start expanding. With soft brass, the neck can be pushed down into the shoulder area.
AND, that's enough to piss off the Pope.

 

[butchlambert]

Hey Butch. Would you do the same going from 6BR TO 30BR? I’m about to head in to uncharted waters with this 30BR thing. Was thinking expandirons in two or three steps to get from .243 to .308.

I chambered a 223 barrel in 30BR for fireforming. Not a miss type, I do use a 22 cal barrel as that was what I had at the time in the tomato stake pile.

 

[JRS]

From experience: Be careful about annealing BEFORE you start expanding. With soft brass, the neck can be pushed down into the shoulder area.
AND, that's enough to piss off the Pope.

If the brass is new/virgin, it's already annealed.

 

[Dusty Stevens]

Hey Butch. Would you do the same going from 6BR TO 30BR? I’m about to head in to uncharted waters with this 30BR thing. Was thinking expandirons in two or three steps to get from .243 to .308.

K&m makes a special expandiron to make 30br from 6br. Works like a champ- one pass and youre ready to go