Small rifle or small rifle magnum primers for .308/.260 SRP brass?

Yes, you can use them. I use srm’s for the durable cup, but many are using standard sr primers. If your match primers are cci br-4’s, they’re the same as your 450’s in cup thickness and priming mixture quantity.
 
Never loaded SR 260 or 308, but I had phenomenal results with Rem 7.5 BR's in Starline SR 6.5 Creedmoor brass. Lots of people use CCI 450's too though, I've been playing with some in 6.5x47 since I'm low on 7.5's.