I’ve been having quite a time figuring out 6.5mm cast loads. I’m using the RCBS 6.5-140-SILH cast of Lyman #2 sized .264 and .265 and lubed with Saeco green. I’ve tried it with published loads of A5744, non-published loads of Unique (10 – 13gr.), 2400 (15-16gr.), and IMR 4831. I’ve seated the bullet from .02” off the lands at 2.725” to jammed into the lands. The best I can manage is 3” at 50 yards, but not if I fire more than three shots. I always get fliers and sometimes several in a row.
I’m neck sizing, trimming to 2.025, expanding with a Lyman neck expander, taking the bell out with the Lee factory crimp die, and completing sizing and seating with RCBS dies.
I’ve never come to a point where a bullet just will not work. I’m curious if I may be at that point, and if so, what other bullets may give success. The only thing I haven’t tried is casting with straight Lino but I wanted to post this in case I didn’t think of something more obvious.