Re: Do you precisely measure your M4 .223 loads?
I pick a powder that will meter well out of a Dillon 650 progressive powder thrower. I'll work up a 5.56 load in .2 grain increments that also shoots good with the group above and below it in powder charge. This way if the powder charge is off .1 or even .2 grains (but .2 grains is a high variance), the ammo will still shoot well. If it's a very finky load that has a small sweet spot and the loads above and below it are crappy, then I'll try a diiferent powder and start over.