I was having a problem with a target dot 8x32 scope so I called Mueller and spoke with Dave told him the problem and the only question was where did you buy it.He said send it in and gave me the return address told me to included the required fee($12) and said it may take 2-3 weeks for a return.
Well it only took one week and a scope was returned to me brand new with a note stating the one I had was defective,bad side focus adjuster.
As far as I can tell Mueller's customer service is as good as anyone's and I would not hesitste to buy another.Actually I am thinking about thier 1x4 for my AR or maybe the shotgun.