If you scaled up our 131 ACE it would be 142 gr 0.264 and carry 0.350 G7, which does not suck. Scale down to 0.243 it would be a 0.326 G7 and 111 grains, which does not suck. The 6mm print we have is not 111 grains, but we won't get to it for a couple of years.
Perhaps the components of a bullet's design have an effect on external ballistics.
Instead of waiting years to see how 25 cal progresses, how about I just post a full length video of our Oehler 89 testing in addition to the full write-up? I don't mind providing actual data.
We want our shooters to hit small targets a long ways away as often as possible.
Sierra has a 110 smk that has a posted bc by sierra of .617 @ 2600 fps and above .605 @ between 1900 and 2600 fps .580 @ 1900 fps and below. Seems decently close in terms of performance to the theoretical 6mm blackjack spoken about above. I'm shooting them now in a dasher and have shot them in an xc with good luck. Could not get them to run in 3x 6 creedmoors.
Using Same thing with 230 smk, .51 x 800g1 = 408 g7 which with some rough math is what a basic scaled up 131 blackjack would be if it was 30 caliber. +/- a percent or so.
Given that they are very similar, it seems that you and sierra have a very slippery design on your hands.