Yep Ackleys data is based on using full length 30-30 brass....where the typical 6mm 30-30 Imp. nowadays is shorter and holds less powder. I have a few really good loads for different weight bullet for your 6mm 30-30.....excellent 58 gr. V max load and a small deer/coyote type hunting load using heavier bullets. I can Pm..............
Freds data on the 6mm BullberryImp is a great place to start......my 6mm 30-30 is very similar in dimension as the overall length is the same. The case body on my imp. is longer but the neck is shorter.....gives me a little more room for powder and little more velocity.