Ok, A week or two ago I put a post up about tight cases when closing the bolt of my 243. I had some great groups but the case was not right so I have turned the sizer very slightly to push the shoulders back a little and this has helped the cases fit and they fit well. The new problem is that the groups are now shocking, can't get any better than 2 inch. Have tried bringing the powder charge up from the low end 37.7 again upto 41.5 The best being 39 grains which was where i was to begin with, which are still the best , but still crap.
I am loading 39 grains of IMR 4320 with 75 grain BT hornady cci primer in a fedral case.
Where do I start from, where do I look first?