Couple things to keep in mind or tips are as follows:
1) use fire formed un-sized brass
2) make sure you slightly bell the mouth
3) use the expansion die from your press to place the balls, don't thumb them into the case. I back my Lee expansion die out about 4 full turns, sit the ball on the mouth, bring it down until it just touches the ball, then slowly 1/4 turn at a time or less, bring your die down until the ball is just barely past the 1/2 way point. This ensures consistency in your seating.
4) if using molded balls, if the mold line is visible, make it match the hemisphere of the case mouth
5) use large magnum pistol primers
6) I recommend using a Lee Factory crimp die, because it doesn't deform the ball as I found the taper crimps tend to.
7) if you are going to carry them around in pockets or in moist areas, I'd dip the tip just past the edge of the brass into Lee Liquid Alox and hang them point down to dry. I use a cardboard box with some slots along the edges to hang them and then any drips drop onto the lower part of the box.
I only keep 20 unsized brass for making these up and keep them separated from my other brass. You should be able to get almost unlimited reloads since they are low power.
This is what I've found keeps them fairly consistent. I get about 4" groups at 100 yards and it tightens up significantly as things get closer. Killing a woodchuck with one at 100 yards is cool. Note, you will probably need to kentucky windage your sight picture as mine don't shoot to POA in my guns anyway. Have fun plinking.
