At the range this morning,working on load refinement for deer season.Had 25 rounds of 25-06,100 gr Nosler Ballistic Tips,H4831sc,52.8 gr up to 53.2(previous testing showed 53 gr load a good place to start).Winchester LR primers,Winchester brass.At this point I should mention that previous testing was exactly the same except that I'd used Remington brass.At 53 grains,previous testing was fine.At my start load today,I experienced heavy bolt lift and cratered primer.The primer began to stop to crater as i got closer to my max load.Is the brass responsible for this?

winchester brass is known to be less than remington in the powder capacity department,..therefore you reached higher pressures with the same powder charge. Back the charge down 1 1/2 grains and try working from there with the new brass. Less capacity necessitates less powder to reach the same pressure and velocity.

I should have started with a disclaimer,....
this is what I have found in my loads.

In your last sentence you said the cratering was going away as you approached your max load. I suspect that the Win case has more internal volume than the Remington resulting in somewhat less pressure. "Probably" the start charge you loaded in the Winchester case was a "very" mild load in that case. The primer could have been pushed out of its pocket hard against the firing pin since the fired case would be forward in the chamber with too little pressure to cause the case to expand and "grip" the chamber. I've found that often, not always, that Win cases have more internal volume, lighter and thinner, than Remington. Both are good cases but as has been said, you need to work up loads specifically for each case or component and not use the same data when switching components.

I don't want to sound like a mother hen but it's a fact that there are capacity differences between Winchester and Remington cases that result from diffent thicknesses of the brass. The thicker the brass the less the capacity. Generally this won't amount to more than 1 or 1 1/2grs. so if you stay about 2 or 3 grains below max you'll probably never even notice it.
Best wishes.

Cal - Montreal