I have a 6x45 that refuses to chamber factory 223 brass that was full length resized. Nothing wrong with the chamber measured with Go/No-Go gauges. I got the advice to fireform. Have done so and the cases now feeds fine on their own until the bullets are seated and I have the same problem all over again. Outside neck turning the cases helps, but I'm not sure that outside neck turning was invented to overcome tight chambering. Any help would be appreciated. Thanks, Adam

Bet a dollar to a hole in a doughnut you are NOT FL sizing correctly. Turn the sizer down a bit, 1/16th of a turn should do it (about 4 1/2 thou).

The real purpose of outside neck turning is to fit the neck of the brass to the chamber. If the bullet is not interfering with the lands, and since turning improves the situation, it looks like the neck needs to be fitted to the chamber. If the spec of the chamber is not available, a chamber casting can be made to determine the dimension. Or, since you have been able fire-form some cases, you can measure the O.D. of the neck and compare it to the neck diameter of a loaded round. You want about 0.002" clearance after allowing for 0.001" springback of the fired case.

I am with winchester69 on the chamber cast,it will tell you a lot.

I'll throw a nickle in the grass for a tight neck chamber.
Measure neck thickness of the brass U are using, and outside neck turn cases if that's the problem.

Just to report back that the problem was in fact doughnuts that formed when resizing virgin .223 brass to 6x45. But by fireforming and thereafter inside neck-reaming the cases, the problem disappeared and I was able to easily chamber the loaded rounds (the bulging neck caused by the bullet pressing against the doughnut had previously made chambering almost impossible).

quote:

Originally posted by Jim C. <><:

Bet a dollar to a hole in a doughnut you are NOT FL sizing correctly. Turn the sizer down a bit, 1/16th of a turn should do it (about 4 1/2 thou).

I use small-base dies for my .223s and turn the die one-quarter turn past contact. No case ever fails to chamber.