O'Connor used military surplus H-4831. Apparently H4831 has been through 2 iterations since the H-4831 O'Connor used and is a bit faster. I have a Handloader's Digest with an article on handloading for the .270 by O'Connor and O'Connor himself mentions in it that his 62 gr load is with the military surplus version and the new (at the time - 70s since the surplus supply ran out) manufactured H4831 and dupont version (imr) are both faster than the military surplus version and require lighter charges.
Lou
Last edited by Lou_270; 12/03/12.
