Trimming 300 wsm brass

[K-HILL]

Resized the brass then measured. Findings were that the brass needed trimmed . Using RCBS trim pro and proper shell holder, so found some of the cases extremely hard to get into shell holder . Never had this problem . Any help would be greatly helpful .
Thanks

 

[LoneTraveler]

Been there and done that. Glad to help you.
If you are using a standard H&H Belted case, NO. 4 RCBS shell holder it is not an exact fit for the 300 WSM case. RCBS lists a shell holder for the WSM Series of cases as RCBS Shell holder NO. 43. I had a RCBS No. 4 and started loading 300 WSM with it. Next 100 pack of cases I got would not fit. Got to investigating and ended up ordering a NO. 43, Problem solved. I just went and got my shell holders and measured them. My RCBS No. 4 opening is .468 My RCBS- NO. 43 opening is .480. That .012 difference is the problem.
Good Luck and happy loading.

 

[K-HILL]

Unfortunately the problem isn't the shell holder . I am using a #43

 

[tailbon3]

I've had that problem too with one specific batch of winchester brass. Somehow the cases were manufactured with rims that were too thick to slide into the shell holder.