243 Winchester Revisited
After following Jim Scearcy’s chronicle of his experiences with the 243 and cast bullets, I decided to dive down this rabbit hole myself. I have signed up for both the Spring Warm-up and the 200 yards combined postal matches (among a number of others) and plan to use my cheap little Ruger American 243 with a 1 in 9 twist. My only mold for this undertaking is an RCBS 243-95 which, so far, has produced absolutely beautiful little pills cast from WW+2% that I size to .244, gas check and lube with Carnauba Red from White Lubes.
For my starting point, I am using Lyman 49’s recommended accuracy load of 13.5 grains of IMR-4198 loaded to an OAL of 2.610. I loaded 20 of these and ran 15 of them across my chronograph to a 25 yd target. The results are promising. The load averaged 1600 fps with a standard deviation just under 20. I attribute some of this variation to the fact that I user mixed, untrimmed and unsorted brass for this test.
Running the data through the ballistics calculator shows that this load, while good at 100 yards, would be transonic at the 200 yards mark. I will need to bump the velocity at least another 100 fps to maintain supersonic out to 200 yards. My next tests will involve raising the powder charge in half grain increments from 14.0 to 16.0 grains and shooting 10 shot groups at 100 yards. I’ll then take the best from that out to 200 and see what it will do.
Film at 11……..