I purchased, but have not picked up a H&R Handi Rifle in 300 Blackout. I currently cast LEE 200 grain GC based boolits from straight wheel weights. I size them to .309, then PC them for a final diameter of about .311. Been shooting them subsonic from a 308 pushed by W231. I haven't done any conclusive testing due to lack of time as far as if they are being sized down when I seat them.
I want to order dies for the 300 and am wondering if I should order a .309 or .310 expander ball assembly. I may shoot jacketed full power loads some time so the included expander ball will work fine for that. From reading about case forming, wall thickness of some cases makes for neck thicknesses that are too thick and I'm thinking that running a slightly larger expander will be beneficial with cast boolits. I'm not gas checking as of now and would prefer not to chance them going through a suppressor. I'm leaning towards RCBS Small Base Dies in case I really like the caliber and end up with an AR. The RCBS dies have a taper crimp.
If anyone has one of these rifle I'd appreciate any advice you have for subsonic cast reloads. Actually I'm open to any advice from anyone.
Maybe I just need to run them back through the sizer after I PC them? I know, slug the bore, but I don't have it yet.