Older post I know, but try Leverevolution for that 20 Practical with the 40gr Vmax. Mine is the Tactical, but by all reports case capacity and ballistics are the same between the Tactical and Practical 20s. (I went with the Tactical because it's actually simpler to make brass; just a single pass of 5.56 brass through a Hornady FL sizing die and it's ready to use, no fireforming needed, or swapping bushings from a 223 die as some of the online resources recommended for the Practical.)
I'm using a 24" AR with this load to push the 40gr Vmax at 3,885 fps avg in converted LC brass and a CCI 450 primer, and accuracy is excellent. For cooler months, it takes 29.0gr to do that in my rifle; for hotter summer shooting back it down a bit to match the same velocity. This load (like most Lever loads) shoots best when pushed near max, but I've got 6-8 loads on some of the brass with no signs of primer pocket loosening so it's not unreasonably hot. The powder charge may be different in your rifle of course.
Incidentally, that 40gr Vmax shoots better than any other bullet I've tried from that rifle, and it likes this Lever load best of all. The little 24gr NTX bullet will do 4,800 over AA2200 from the same rifle too, but terminal effect on sage rats is better with the 40gr Vmax.