I'm a bit stumped...
I'm loading 350Hdy's over IMR3031 in a Marlin Guide Gun. I started at 54grs and noticed heavy swelling at the casehead. I just thought I was a bit heavy on the charge. Backed down to 50 & 48grs with same results. There is no way 48grs is too heavy....so what now? oversized/sloppy chamber?
350Hdy FP crimped on groove
WW Brass
Fed210
Thanks for any input
