Hello All, I've been reloading ammo for a couple years now. I lucked into thousands of new 10mm nickle/brass Starline cases a couple years back. While I was learning in the in's and out's of reloading the 10mm, I loaded new brass. Now I'm about halfway through my brass and and have started to load my once fired brass. In my first batch yesterday I noticed something yesterday - bullet creep. I loaded some Nosler 200gr bullets into once fired Starline brass. I measure for length and headspace gauge about every 20 rounds. I measured the 60th round right at 1.250 inches. Then I kind of accidentally 'slammed' the bullet into the headspace gauge, and upon inspection, noticed the bullet was popping out of the top. I measured it and the OAL was now 1.270. I went back and tested the other 60 rounds I had made so far, kind of slamming them into the gauge. About half expirenced some bullet creep of approx 0.02 inches. I couldn't pull the bullets out with my hand, but there was some creep. I checked every station on my Hornady progressive press. Everything was in spec. I tighted down my taper crimp another .002 just to get it more snug. I put those 60 rounds back through the press just to crimp them, put them in the headspace gauge and still had creep. I tried two additional bullet types (Hornady and Speer) and got about the same amount of creep. Then I tried those three bullet types with new brass, and guess what? No Creep. My press has five stations and is set up in this order: 1. Size/deprime/prime 2: Flaring and powder drop 3. RCBS Power check/lock out die. 4: Bullet seater 5. Taper crimp die. All dies except lock-out die are Hornady. The resized brass is falling right into spec at .421 inches external diameter after sizing. My taper crimp is at .420. The only remaining variable that could be causing the creep is maybe I'm not cleaning the brass enough. Could residue on the inside of the brass prevent the bullet from ceasing properly inside. The outside of the cases are nice and shiny, the inside of the cases are a little "Cloudy" still. Some have just the teeniest bits of carbon left in the web area. I used Lyman treated corncob media with bits of paper towel and dryer sheets. Do you think this combination of media could be making the inside walls of the case 'greasy' preventing the bullet for making good contact against the case? This only seems to be happening with my 10mm loads in used brass - the other calibers I load haven't experienced this. HELP!