I used Lapua Palma brass (small primer pockets) ALMOST exclusively for my 308 family cartridges for many years. Two things:
1) Nodes will usually move slightly, so your loads won't be interchangeable, simply because the brass is different, not necessarily because the primers have changed. Powder choices are the same, but the internal volumes inherently change, so nodes move around.
2) Sloppy firing pin bores may be more likely to crater or pierce as you swap - I didn't personally have issues, and many, many shooters do not, but some do. This isn't really an indication of increased pressure, but rather just acknowledgment that the primer cups of SRP's are thinner and more prone to show pressure signs than LRP's. If you're loading top-end or over-max pressures which are on the verge of cratering LRP's, you might find yourself piercing SRP's with the same load.
And a bonus 3rd item which is more subjective than the others:
3) Unless you're competing at a high level, I'm not sure I would spend the money to BUY Palma brass nor spend the time to FORM Palma brass into these other cartridges to be used in M1A. It eats up brass in normal operation, and flings it far and wide, so unless there's a true driving purpose behind the idea, that particular juice would not be worth the energy for me to be willing to squeeze it. I have not used enough Peterson brass to really have an opinion on it - and have used NONE of their SRP 243win/260rem brass - it still ain't cheap, but at least you don't have any sweat equity invested to form the brass.
