Let's see...
1. Don't forget to put the cap in your powder and shot bottles on your MEC 9000. (vacuum's don't pick up # 7 1/2 shot very well)[I know this is the rifle section, just figured I'd that tidbit of hard-earned knowledge]
2. verify powder levels in your cases BEFORE you get the bullet in (pointy end up, of course)
3. when using a 1500 to weigh out your loads, make certain you don't have it on grams instead of grains (unless you're loading via metric loads that is) 50 GRAMS of powder will over-flow your little cup thingy.
4. double check the bullet weight before loading to make certain you aren't putting 100 grain bullets on a 120 grain load, or vise versa.
