I was in a store a couple weeks ago and on a package of Nikon bases it said something to the effect of "Manufactured by Warne for Nikon". So at least some of Nikon's bases are actually manufactured by Warne.
Another fun "manufactured by" story is that All of Vortex Precision series rings are manufactured by Seekins. So, save yourself some money and buy Vortex Precisions instead of Seekins.
For what you are looking for I would think that aluminum rings from nearly any of the companies mentioned would serve you well. Despite what others may say I would go with aluminum. Steel will rust more readily than aluminum will corrode, especially with today's Al coatings that everything has on it. Blued steel bouncing around in a truck or on an ATV and the temperature swings from baking in the sun during the days of summer to fall temperature swings from day to night...I'd go aluminum. Al does have a bigger sensitivity to temperature than steel in terms of expansion/shrink with changes in temperature but I'd not think that will matter a whole lot to you if its setup in a pretty standard A/C environment in the low 70's.
I just received some Zeiss aluminum bubble level built in rings and man are they nice. Most of the bubble levels I've seen protrude quite a bit and something about a glass vial sticking off the side of an optic didn't sit well with me. Asking to be broken. I liked the Zeiss design because the bubble level section is well recessed and protected by the structure of the ring. So I went with it.
Great info about Vortex and Seekins. The Vortex military discount program is
one of the best + the Seekins made for Vortex are US made.
