I would like to suggest you try Ramshot Hunter as it is a spherical powder with a burn rate in the 4350 range.
It may be easier on your throat than the stick powder alternatives. (I own a Hodgdon hat ...
It is advertised as being temperature stable. I can not comment on that though as I have not tested it.
Something to consider as the 22-243 may be somewhat overbore and may have a short throat life.