Interesting read guys, and will chime in with a couple of thoughts. I have been casting for my 404J and have tried lots of combinations, from 2206 to 2209, (3031 to 4350) but found tht I could get best performance, ie velocity and accuracy, with the same powders that I used for jacketed, as in 2208 and 2209 with over 2400fps easily obtainable with 350gn GC HT and with straight lino GC. I always use Mag primers as we are talking up to 84gn 2209 and 74gn 2208. I use my own lube which is simply 2/3 bees wax to 1/3 vaseline and have had very good results with it right up to the highest velocities I have obtained.
For reduced loads I have been playing with Red Dot following advise on the Cast Boolit forums as it is very insensative to position and volume in the case and is very clean burning like trail boss. I have tried it with smaller cases as in the 7x57 and 11.5 gn gets me 1500fps for 160gn GC and lots of loads from a can. They have a standard load of 13 gn as starting place and standard for all cases of 30 cal and above ( excluding those like the x 39 variety) and including the 458 win so that may be a good area to investigate for the Taylor. I intend to try from 13 -18 gns in my 404 at some stage as A 4kg of 2209 dosent last long at the big scoops it takes to feed it.

Von Gruff.