ozhunter:
My Jeffery .400 regulates with 81gr AR2213 and the 400gr Woodleigh. Graeme Wright recommends 80gr IMR4831. No filler or wads are needed. Both these loads give velocities at or just above 2000 fps in 24" barrels.

I haven't developed a load for AR2213-SC yet as I bought the old powder in bulk and still have a few kgs to get through. Working on it, though!

I'm betting that your Searcy will be regulated at 2150 fps at normal barrel-length, and why not?, with new steel and modern powders. Start at 80gr AR2213-SC and adjust accordingly, till it regulates. Use a chronograph, very important, and don't exceed 2150 fps. If it comes together a bit under that, bonus. Margin for error. Remember that with a double, you are seeking perfect regulation NOT best ballistics.

As others have advised, if all else fails, ring Butch!