Yes I have done that with no significant difference between the two lots. But, I was using them for casual practice, not competition.
Some match shooters like to stay with the same mfg for their practice brass as their competition brass. They say the slight differences between their competition brass and other mfg brass throws them off during practice.
If you don't shoot competition, and you intend to use the brass for practice, then you shouldn't have to worry about using a mixed bag. I've been doing that for years without a worry.
[This message has been edited by feedramp (edited 11-14-2001).]