Try this: Lubriplate "SFL" NLGI #0 grease
"... Again, food machinery greases are ideal for our needs. For such things as autoloader slides and rifle bolts, my favorite is Lubriplate "SFL" NLGI #0 grease (their “FGL” line is a good second choice.) In my testing it's proven itself superior as a general lubricant. It is white, aluminum-based, low odor, has superb boundary lubricants, and is designed specifically for use in environments that encounter a huge temperature range. It's also resistant to water washout and acid/alkali environments, has great shear resistance, and doesn't oxidize like lithium greases will. As an all-around grease I've found nothing better. It's available from
www.lubriplate.com, in their online store. It comes in a 14oz can which will last you for years - no matter how many guns you have!
(Lubriplate also makes SFL in heavier grades, such as NLGI #1. While thicker than the #0, it is still a pretty light grease, and would be my recommendation for very hot climates. The NLGI #0 is a better choice for most of the United States.) ..."
From here:
http://www.grantcunningham.com/lubricants101.html