Re: Which NF NXS for this application?
RE 50mm vs 56mm: I have used the same rings for both scopes. So there is no 'cheekweld issue' between the two for me.
I am on the list at CSTactical.com right now for 5.5-22x-56mm, Milrad Speed Turret w/zero stop, and Mildot Reticle. All the new NF NXS on your wish list are shipping with the speed turrets (improvement) and zero stop, so make sure you are getting one of them when you order.
I went to Mike's shop
www.cstactical.com and looked through the 3.5-15 and 5.5-22. I have owned them both in the past, but wanted to look side by side 'one more time' before a final decision. I went with the 5.5-22 again because I don't feel I am losing much on the bottom end from 3.5x to 5.5x for close range, scans, etc., while at the same time I am gaining a lot on top if I want to spot for others, identify targets at distance, or see holes in paper further than is possible with the 3.5-15x.
They are both very similar in size/weight as well, so there was really no reason not to get the one with 30% more magnification, it can always be turned down.
I think the 3.5-15 excels where you would need that low magnification, for example (1) fast movers or targets of opportunity for limited time under 100 yards, or (2) if you need to glass large areas and dont use binos. I would use the gas gun/ACOG for situation 1 if available, and the 5.5x would suit me fine for situation 2.
If you get the 5.5-22 and would rather have the 3.5-15, it would take you about 15 minutes on here to do a trade with cash added from the other guy, but unlikely if the situation were reversed. Food for thought.
Here is a 5.5-22x56 on a 308. I dont consider this too much scope for my use.