Re: Who makes good brass for the 7mm rem mag?
Well I have used Remington, Winchester, Federal, and Hornady, take your pick, in my rifle they all shoot about the same as far as accuracy. That said, I find different issues with each brand after a few loads.
With some, the pockets seem to loosen up really easy, others stretch lengthwise excessively to the point I only get a couple of loads, some as you mention seems to get loose necks or excessive spring back, which I haven't tried annealing yet.
Overall the most used in my loads is Winchester, with Remington being right there along side. The accuracy load in my rifle will shoot both brands into nice 3/4" or so groups at 200yds using the 162gr Hornady SPBT.
If your set on Win or have a large number on hand, go ahead and pull out 10 or so and do the anneal on them. At least you will find out if that is the issue. Lets us know what you find out.
Mike / Tx
"Heck why would I lie, most folks don't believe the truth when I tell them"