Finally got a chance to really work out my new 91/30 at the range a few days ago.  Looks great, shoots great, kicks like the bitch I want it to, good stuff.  Aside from needing to bring more ammo and adjust my sights better next time, it's awesome.

One thing that's concerning me, though, is that it seems to be scraping the casings when I lock the bolt.  It's not a deep gouge--it's more like a wide (three, four milimeters wide) scratch that leaves a tiny curl of brass (literally tiny) towards the end of the scrape near the rim (it's scraping mouth to rim).  It's intermittant in size and severity, and it seems to be happening somewhere around the two, three, or four 'o clock position of the chamber, about a fingernail's width in.  I've looked around with a bore light and felt around with my pinky, but I can't feel a burr and there's lots of thick grooves right in that spot where the lugs on the bolt head lock.

I've put 40 rounds through it without the smallest hint of a problem (50/50 FMJ / JSP mix of the new black box Wolf non-corrosive, but I still scrubbed it like corrosive ammo), but it's still niggling at me.  I'm also wondering if it might be contributing to the stiffer than usual bolt my rifle has, even for a Mosin.

This something I should worry about or have checked?  The marks don't look even close to compromising the integrity of the case, but I'm not exactly an expert.

You may want to look intothe chamber area.  You may see a little burr in there that is scratching the casings.  Also, get a larger bore brush that will fit snuggly into the chamber area.  Attach it to a rod and then you drill.  Dip it in some Hoppe's No 9 and scour out the chamber.  The stickyness may just be some hardened crud in the chamber area.  Pretty common on milsurps of all sorts.