Ive reloaded 5.45 and while it is a lotof work can be rewarding. Reasons? Accuracy, better bullet performance both BC and terminal. Ive got down to about 1.25 5 shot groups at 100 yards, and the rounds are great on groundhog.
I started from data from pomofo and bolt2bounce over on akfiles. The procedure runs some thing like this: run 222 through sizer without ball. Use drill to ream, as the thick shoulder becomes part of the neck (if I had a neck turning tool that would be better, I know) then run again with ball. Ive discovered that Lapua brass doesnt need to be annealed which makes it worth the extra cost. Another option is to do Mexican match from commercial steel ammo. You save a little by using brass, as brass life isnt great. Ive cut open brass after resizing and sucessive reloads - I havent pushed beyond 4 reloads.
Ive reloaded both the 221 hornady bullets that midway carried (great bullet) as well as resized 224 bullets. Resizing is quite east: just drill a 221 hole the a peice of steel and use a punch. Alternatively some fokks custom ordered from Lee. Im currently playing with the Berger 75s (.423 BC) and have some JLKs 80s on order (.510 BC). Try that at mag length with an AR - in theory the short 5.45x39 cartridge should do well with heavy sleek bullets. I am still playing with different powders, for now BLC-2 and 748, next Varget, 2015, 1200r and AR-Comp.