Isn't there a shortage of new 300WM brass right now?
What's reasonable to me might not be reasonable to you, right?
Tell us what he's offering and maybe we can comment on whether the price is reasonable, or not?
A dollar a case?
If you're shooting a match next week and you use a 300WM and you think that you can win that new car that they're giving away by shooting your 300WM, you might think that $5 a case is worth it for smaller batch, no?
If the RWS group buy guy is thinking ~$1.50 a case for new Swiss, or German production, than 1x USGI brass should be less than that, but if you need it now and can't find it, you'll just have to pony up and bite the pillow.
Chris