kimber denting brass

[bear300us]

Hi im new here an new to reloading,my almost new kimber is denting the brass about a 1/3 to 1/2 way down,dose anybody know why?im loading 230 lrn 5.5 grains of unique almost everyone had the dent.they are ok out of my 4506.i racked some rounds through the kimber an one had a slight ding.any suggestions would help.
Thank You ED Mink

 

[DnPRK]

Your empties are hitting the back of the ejection port. If you look closely, you'll see brass marks there. Does it dent brass with factory ammo? If not, you could switch to a different powder/load. If you're absolutely in love with your current load, a solution to late ejection is to tune the extractor and swap your ejector for one with a longer nose.

 

[Scorch]

230 gr FMJ over 5.5 gr of Uniques is the same load I use for hardball when I load it.

As DnPRK said, the ding is from the rear edge of the ejection port. If the port has not been scalloped, most of your brass will pick up the ding. It is caused by the extractor holding the brass very tight and the nose of the extractor being too sharp and not releasing the brass as the ejector strikes the case. Fit the extractor (bolt face to hook clearance, radius the tip of the extractor) and make sure the extractor is not clocking (rotating in place when you fire). If you don't feel comfortable doing this yourself, it is a relatively simple task for a gunsmith.

I wouldn't worry too much about the ejector, it seems to be hitting the case hard enough to drive the case against the port.