If it's new or known low pressure load brass I don't worry about it. I figure it's insignificant.
(Loose is a relative term)
If the primer is loose on reloaded brass of high pressure loads or unknown origin, I scrap it. (And reduce my load if it's mine)
(I recently talked with Stan Watson of the Lawton OK area and I believe he mentioned that primer pockets get blown at a pressure of about 73,000. 10,000 to 11,000 above most safe loads if I recall correctly.)
Thanks, it is on reloaded brass and probably because of too hot a load, so I do back off my loads but wondered once they got loose (will still hold a primer), if they have to be scrapped (trying to avoid prepping and fireforming new brass).
Directly affecting accuracy?? I would have to say no. The only thing you need to lookout for is when they get really loose and start leaking. you'll notice a black ring around them. You've got to be careful of this because eventually you can damage your bolt face if it starts to get gas cuts in it from leaking primers.
Image of a leaking primer:
Image of the boltface from the fired case above:
So the million dollar question is how loose is loose? I've had primer pockets that were loose enough that I could put a primer on a table top and put the case over the top of it and with very little finger pressure seat the primer. WAY to loose and gas leakage will happen if it hasn't already. if you have to use finger pressure to seat them using a priming device that has any type of mechanical leverage system, you should be ok.
also as a standard safety disclaimer.... how many firings do you have on these cases when you notices the PP are loose? As in very loose... If it's only a 3-4 firings you load is on the upper end of the scale and you might want to back down some. If you have more than that, then it's up to you. Is it "save case life" or stay with the accuracy I've got. just watch if the temperature goes up from what you've been shooting is all. Also if there's any doubt about the looseness of the primer pockets, and these case aren't some exotic caliber, throw then away. It's one of the cheapest parts of safety equation in handloading.