Hello, first post on this forum. Got a question. One of my 10s, STI 2011, occasionally causes a case bulge above the case head. I've only noticed this with Starline brass, Winchester no problems yet. They're easy to find when I'm resizing cases. The result is a smiley face and a tiny crease, very thin. I dissected a case, and the smiley is right above the case head. I don't see anything on the inside of the case, although the case head expanded 5.5 thousandths. Case wall thickness looks to be the same as new. Up until now I've been tossing them, but I think I'd be safe using them for lighter practice loads. So, I guess the question is, how much case head expansion is too much? Thanks in advance for your replies.
Hello and welcome to the forum Likemy10s! We consider a distinct line as a smile where the brass is starting to shear on the molecular level. If you could post some pics that may help out too.
Pass-through sizing helps with those cases with smooth rounded bulged cases to iron them back to a useable condition. This may help your brass for the target type loads if they aren't very bad...
See this section about smiled brass
http://10mm-firearms.com/reloading-10mm-ammo/cross-section-of-a-smiley/msg2175/#msg2175 (http://10mm-firearms.com/reloading-10mm-ammo/cross-section-of-a-smiley/msg2175/#msg2175)
Thanks Shadow, excellent info. Seeing those photos helped. The case I halved looks just like the picture. The corner ( which would be at chamber top) is a clean 90. The corner at the ramp has the rounded and down shape. I cut two more cases, one had a small wrinkle from sizing but no smiley. It looks good to shoot. The other has the smiley and I can feel the bulge on the case with my nail it has the rounded bulging corner internally. I was shooting 200 grain hard cast with a pretty hot charge (just under max). Longshot powder. Like I mentioned I had no problem with Winchester brass. I'll have to look into this a little more, for now I'll cull all the brass with the shiny marks but no bulge, use them for lighter loads, and keep an eye on the Winchester brass and see how it holds up. Brass where I can feel the bulge after sizing will get retired. One other thing: they were once fired cases, they didn't have the marks after the first firing but I was shooting lighter bullets.
Welcome Likemy10s