I just pulled my bore guide back a tiny amount and scrubbed wth a 6.5 nylon. I’ll get a 7mm bronze ordered.
Thank man
Just stay on top of it so it doesn't build up and it'll come off easy. Plain Hoppes #9 works fine for me. You don't wanna be using a dental pick in the chamber. Always use a material softer than the metal you are working on, so bronze, brass, etc. Eventually the brass will lengthen, how long, how many shots I guess you'll have to ask the Tootsie Pop owl...
It's happened to me too. I tend to clean often enough though including the use of a chamber brush, so I never encountered any problems with the chamber. Some LC military brass would actually come short from the factory and as long as it was just a few thousandths and there weren't any problems and nobody complained, it didn't get recalled.
A taper crimp may help stretch the neck out some too, but personally I wouldn't use the Lee crimpers or ones that do a deep crimp in the cannelure on that brass. A lot of rifle seating dies have a taper crimp built in.
I use a 650 press and an auto trimmer now. It's made it so I take trimming for granted, trims brass if it needs it, doesn't otherwise, and needs no chamfering or other work after. All my brass is uniform, which makes factory crimping in cannelures spot on. Worth looking into, surely speeds up loading and it cranks out ammo as good as your dies and habits Wish I'd got one years ago..
