Eddie,
Try different brass if you can get some - Norma - RWS - Winchester. These are normally very reliable 'everyday' brass. No one gets excited about the weight or apparent strength of these cases besides the heavier brands, but my experience is that in general they are very reliable.
If they work better - then get rid of the other stuff. I've witnessed a .25-06 get a bit 'picky' with some cases which were hard to extract after firing - some had to be rodded out at home which was a darned nuisance when out at night foxing, and it became the norm to have another rifle with the fellow who was doing the lamping.
A change of case brand solved the problem.
As has already been suggested earlier in this thread, try to put the hard extraction cases aside - in a different pocket, and see if there's any comparison between them - then afterwards - the others which extracted normally. Outside case dimensions at shoulder and base - length from base to shoulder - diameter dimensons at neck - (Inside and out).
Too thick a neck wall, pushed outwards by the seated bullet, might create a crimp effect when the cartridge enters the chamber, especially if the chamber neck is a bit on the tight side. We all length-size the case necks because the brass flows down there - but we seldom think about neck wall thickness.
Remember that during extraction of the case from the sizer die, the neck expander ball on the decapping pin expands the INSIDE of the case neck out to suitable bullet seating dimensions whilst the bullet then pushes the neck that bit further out when seated.
So, there's nothing to govern the size of the OUTSIDE of the neck although all other parts of the case affected by the the die have been squeezed inwards for an easy fit.
I'd start with the brass as Muir says and work on from there. You can see that you could write a small book on its own on this one subject, but one step at a time.
Good luck.