Lead free primers may not work well will all powders. I'd try them out and check velocity variation and accuracy at the least. I can also say that I suspect they aren't the best for extremely cold temps. A normally consistent load was pretty poor when the temps went under 20. Checking velocity showed more variation than when I worked up the loads in warmer weather. Didn't get the chance to put some in the freezer and test them, but did the same basic thing at the range when we had the last cold snap. I've tried a limited amount of the small rifle so far, but have a few other types to check out. I think I'll wait until spring.

It would be interesting to find out if they have a decent shelf life when stored properly. I might not live long enough to find out, but some of the younger guys might have time to test them over 50 years or so.