i've been playing a lot with primers lately, and thought i'd share some data.
loading setup is new winchester brass, 45 acp, in a dillon 1050b with a light load of 5.6g vv n320 and hornady xtp 200g HP. seat depth of 2.225". fired from wilson supergrade compact.
without varying any of those factors, i loaded a bunch of rounds with different primers and chrono'd them. The results (mean FPS):
794.20 FPS - Winchester LP (box says "Large or Magnum")
750.85 CCI LP
750.75 Federal 155 Magnum Pistol
stdev was 16.7, 19.4 and 26.1 FPS respectively
and also interestingly was that while none of the primers flattened anywhere near a dangerous level (obviously, as i'm shooting very light loads), the federal magnum primers showed more flattening than either cci or winchester. probably due to slightly softer material, but i have a theory that the magnum primer might be a bit hotter, resulting in steeper but shorter pressure curve that doesn't translate into higher velocity. dunno.
the reason i went through this exercise is that my winchester primers were giving me consistent rates of misfires around 30% (ack!) so I called wilson and they said they had the same problem and switched to federal. unfortunately, I could only find cci and fed magnum primers in nearby stores, so i decided to try them. I put about 150 rounds of the fed mag load through the pistol with zero misfires so far. I can't wait to chrono regular federal LP primers though.