6.5CM Small primer vs large primer brass

[OTG8]

I have some once fired factory brass and noticed some brands (Federal premium) use small primer pockets and some used large primer (Sako, Sierra).
Wondering if there could be some noticeable differences between velocities and extreme spread or not a factor?

 

[remington jim]

The real benefit of SRPrimers in std head size brass is longer life of the brass due to less expansion of the smaller pockets .
Velocity etc are usually very similar .
Your better of with LRP in colder weather and MAGNUM LRP in
the REAL Cold !