Got my hands full this month working on my sons 308 and my nephews 243. I started out just getting both rounds read, prepping cases and making boolits. Then when the rain finally let off I decided to mess with the 243 first.
I am loading the RCBS 95 grain boolit. Using IMR4227. I started out with 5 rounds each of 13-18 grains. I did load the 17 and 18 grain charges with three different lengths mainly on the hunch that the 1950fps mark is where I need to be(based on some deep research into shooting cast 243).
I should note this is a Rossi gun. 1:10 twist. Needless to say, the lower charge rounds 13-16 were dismal. It dawned on me that the twist rate may be my handicap. I did not see any key-holing, but you could tell there is some major issue. I am still going to play with the higher end loads, 17+(will be loading up to Lymans max of 20.5), but I am curious what others have found out with this boolit in a 1:10 twist.
Would a faster powder, slower powder be the ticket? I don't want to rule out the boolit completely because of the twist rate, as the 17 grain charge seated long(only .243" of boolit in case neck) did group 'reasonable' at 100 yards.
But that is one other thing I question with this, seating length. When people have loaded this boolit, did you all play with COAL at all? I tried 3 different lengths, one book spec as listed in the lyman manual for this boolit. One a little bit longer(not sure where I came up with the length). And the last was by the old way of putting at least the diameter of the boolit, .243", inside the case.
The last one seemed to shoot the best. Its of course going to be the closest to the lands. Rossi's have notorious long throats. I have tried it, but cannot remember(will test tonight), but I could reach the lands with this boolit, but not much would be in the case. Guess I should have measurements before asking for advice....
I think I am going to try some Unique loads also, just for good measure. Truly all I am looking for is a plinking load for him, that can keep the holes in a 2" square at 100 yards, so he can have fun on Christmas with my boy who will be shooting his new gun.
One last thought/question. Would a shorter boolit, like the NOE 75 grain be worth a shot even though it would have a HUGE jump to the rifling in this particular gun?
Sorry for the long ramble, thanks for the help in advance. There are just so many different things to try I feel kind of overwhelmed at this point and still have one more gun to get shooting good after this one is done.