In low pressure/velocity loads probably makes little or no difference. Did notice that standard primers in 243 and 30/06 sometimes caused delayed ignition with BLC2 and Win 748, was noticeable only when wearing electronic muffs. Some had a definite click-bang that would not have been noticeable with standard muffs and plugs. None of these loads were "hot" and a primer change showed no difference worth worrying about. Win primers might be formulated differently as the ones I have seen are labelled for standard and magnum loads. Tried LPM primers in 45ACP when I was burning through some WW452 and WW473 as there seemed to be a lot of unburned powder, but in this case the primer change didn't help. These were low end loads and think the real issue was the load was too light to generate sufficient pressure for a clean burn.