bolt wet or dry?

[whitewalrus]

Wet, any decent oil works just fine, no need for designer lubes.
The Slip mentioned is good, also straight weight Mobil1 works well.

Any reason straight weight vs the 5w-30 or similar popular dual weights?

[BPTactical]

Any reason straight weight vs the 5w-30 or similar popular dual weights?

Just always liked the consistency of a straight weight, it seems to stay put a bit better, no real reason other than that.
I feel regardless of your flavor the important thing is running the rifle wet. I have tried a bunch of different lubes on rifles that are run very hard. Only when run dry did I see any marked wear issues and that was on the upper reciever.
Didnt really see any +- on any particular brand aside from CLP, which to me isn't much of a cleaner or lube. It does work great for keeping a finish looking fresh - ArmorAll for guns.
The only time I like grease is on a heavily loaded sliding fit like a 1911 slide. An AR bolt carrier isn't loaded the same way a pistol slide is.

[Gman]

The only time I like grease is on a heavily loaded sliding fit like a 1911 slide. An AR bolt carrier isn't loaded the same way a pistol slide is.

I like to use grease on the 1911 locking lugs and oil at the bushing. Seems to work well.