I think they give more consistent ignition, I use Federal magnum match primers a lot in 25 06 and larger cartridges a good bit. I try large rifle first.
Hanco,
I don't know if this is a myth or not but I've often heard what you mentioned is especially true when hunting in sub freezing temps. I haven't been able to substantiate the claim for myself however I do take note of it as its been mentioned by some I consider to be knowledgeable.
Trystan
