Fire form 6br brass with cream of wheat

[Grimstod]

My recipe was 12gr of H110 filled to the neck with cream of wheat and plunged with tissue or packing foam. This gives you about an 85-90% form and adequate for head spacing on a BRX.

 

[MarkS]

So I see lots of replies, and will pipe in now.
First I'm looking to fireform my brass 6br to 6br after I have full length resized it.
So with that said what is a good starting point of amount of Winchester WST powder?
I'm guessing that the best plan is to load up the cartridges then holding my rifle with the barrel pointing up, insert the cartridge and shoot.
Doing this repeatably increasing the the amount of powder till the cases are forming correctly.
If all this is correct how much should I increase powder charges by. By 1 tenth or what amount of powder?

No need to FF for a 6BR, put a bullet into the lands and shoot. The fast powder will heat your barrel as much as firing a bullet.

Mark Schronce