Re: 7BR brass ?
I'm using Redding dies for the reloading right now, but would be just as happy with Forster. Both make a good quality product. For the actual necking, however, I use the special die from Sinclair. It has a universal body, and accepts a variety of expander mandrels (which they also sell), and is used exclusively for this operation. 6mm BR to 7mm BR, 30-06 to 338-06, 221 Fireball to 300 Blackout, whatever, all the same die. Fairly inexpensive and does a great job. The mandrels have a fairly long radius tapered on the front portion, which makes for a very smooth entry into the case. With just a touch of lube, they do a great job and make the process a very easy one.