I have seen mention of using slightly reduced hornet loads for the 5.7 on a couple of sites. 2400 and blue dot are both commonly used in hornet reloading, any one experimented with powders other than ram shot and accurate?
I have used Power Pistol and W-W 540, (which is obsolete, HS6 is still available).
There seems to be a small number of powders which work well. The semi-automatic action makes things more difficult. I am sure that a single shot or bolt action could make use of a wider range of powders safely, but the pressure curve has to be just right for the P90/PS90 and FiveseveN pistols to operate successfully.
Longshot and Bluedot both seem like possible candidates. Due to other projects taking priority, I will probably buy a can of TruBlu or HS6 next.