Who makes 6.5 rem mag brass? Where can I get some? Is there some other brass that can be formed into 6.5RM?

Any belted mag brass ie 7mm Rem Mag, 300 Win Mag etc can be formed to 6.5 Rem Mag with the correct form and trim dies. .350 Rem Mag brass can be necked down as well but I imagine it take a few steps down and possibly some neck reaming as well though I am not sure about the last. Sean

Might try this....

Start out with your bullet seating die...
take the guts out...
back the die out untill it barely touches the case
(you are using .7mm cases right?)
Lube the case
Size the case in steps, half a turn on the die at a time
Trim to proper lenghth
Full lenghth size with you FL die

Will probably have to neck ream.

I have made .22/250 cases from .30/06 brass this way just fooling around. It can be done, just takes a little time.

I used to make 6.5 Remington from .264 Winchester with one pass through the die then a trim. 7mm Remington should do as well. Since most factory chambers are very loose in the neck, you likely won't have to ream, but only trial in you actual chamber will tell.