Re: Leupold Mark 4s. Original fixed power vs newer variable power durability
Our M3A's are the original MK4 and they are pretty durable, however they can fail just like any other optic. They used to be the standard to which all other tactical riflescopes were compaired to, but now they just seem generic. I would not be any more concerned about using a variable power MK4 instead of the fixed power originals. We use the 3.5-10 on our M110's and the 4.5-14 on the M107's with no problems...well, no more then the fixed version.