I've always used necked up .30-06 brass in my .338-06. I had the rifle built in '97. I've put over 1000 rounds through the rifle, and I've never had an issue with using .30-06 brass, other than wearing some of it out.


I also have a .30-06 and I have NEVER gotten the ammo mixed up. It's not that hard to tell them apart with a quick glance, but there are a lot of other ways to keep them straight, if a guy wanted to be anal:
- use different colored ammo boxes for each caliber - this is what I do
- Nosler Ballistic Tips are already different colors for each caliber
- use completely different bullets for each caliber
- use different head stamps - choose one brand for .338-06 and another for .30-06
- use nickel-plated brass for regular .30-06 ammo (necking it up doesn't work so well, BTW)