These days, if you are looking for a fixed 4x, your best bet is really a prismatic of some sort.
I happened to intensely dislike the 4x ACOG, but the 3.5x is much more up my alley.
However, there aren't many other 4x prismatics available. While I much prefer the 4x Elcan Specter OS, I think they do not make it any more.
There is a whole slew of good quality chinese-made prismatics, but most are 3x and 5x. There are a couple of 4x ones on the way, so waiting a little might be worthwhile.
Also, most prismatics are really not set up for bolt guns. Their mounting systems are intended mostly for AR-style weapons. However, there are a couple that I expect to come out next year that should be easy to adapt to more traditional guns.
I wish Brownells offered their retro 4x without a carry handle mount. It would work fine with 35mm rings. In principle, the carry handle mount looks removable, so if it might be possible to just remove it and use the scope with regular rings.
ILya