Another vote for 0W-20 syn. Use it with any bolting/gas system, whether rifle or shotgun.
Live in Maine. Rotella 15W-40 is possibly superior in warmer conditions - keeps grit in suspension a bit better. But on balance OW-20, as a year rounder, is best.
Heckuva lot better than CLP, unless we're talking lube for fire control parts only.
