In my experience the 2.5x8 is too short for me on a long action. I would need a rail type base on a long action.
Agreed. As good a scope as it is, it is short for a long action. It will [probably] span a long action with normal rings, but it will end up where it ends up with next to no room for back and forth adjustment for eye relief. Even on a short action, extended bases or rings, or a pic rails, may be desirable to get it where you want it. On a long action, you WILL need a rail, or extended bases or rings to get it where you want it.
That said, Leopold's various VX-3 in 2.5-8 have always been great. I've switched out several Burris scopes for VX-3HDs and now have several in 2.5-8 and 3.5-10. I have no complaints at all. I don't really care for the CDS-ZL knob on top, but it's not obtrusive and I have just set mine to forget.
I've never used a Z3, but looking at the dimension, the 3-9 is actually 1/2" shorter than the Leopold VX-3HD 2.5-8. So, I 'm not sure it will span a long action any better than the 2.5-8.
Of course, the way rings mount on a Tikka it may be a non-issue with that rifle, I don't know. But these shorter scopes can present an overcome-able challenge on more traditional open receiver long actions.
Not sure what you've mounted them on, but I have/and have had 2.5-8's on a lot of long actions without using a rail. Some long actions will fit them with standard mounts, some require an extended front or rear mount. Talley LW extended rear was just the ticket on really long actions such as the 700 and 110. Looked nice and didn't intrude over the action opening; unfortunately, I experienced some failures with Talley LW so I no longer use them. Likewise, Warne makes extended fronts in several lengths. All Warne products I've used through the years have been great. The DD mounts can be had in configurations that allow shorter ring spacing. If you really want a 2.5-8, you can figure a nice looking way to get it on there.
At one point I had 14 2.5-8 in service. I still like their eye relief, non critical eyebox, looks, size and x range for most hunting situations I find myself in. But, like the Talley LW, had some issues with Leupold's, and now I've kinda lost the faith. Still use a lot of the 2.5-8's, but haven't been buying more in awhile.
I had 1of the Swaro's in reference. Had it on an unbraked Weathery ULW in 300. Lost zero after about 300 rounds. To be fair, that rifle has killed a couple scopes through the years. Did some research and found that I was far from the only guy to experience the same troubles, so didn't bother messing with more. Was great glass for sure, but glass quality is down on the hierarchy of importance on a rifle scope.
If you are entertaining a Tikka, use the Sportsmatch rings - that have been recommended on 24HCF for years
- directly to the integral rail, and a 2.5-8 will fit and look great on there. Also, unless you want it twisted different than a factory barrel, there's really no need to do any custom work on the factory metal. Every Tikka I own or have spent time with groups and functions fantastically. I've never had trouble with the plastic, but I have upgraded to MT bottom metal and magazines on the Tikkas I own. Overall I've found the Tikkas to be quite rugged and capable of very tight groups with a lot of different loads. I viewed them as an entry level rifle for years, so I was late to the party with them, but I'm glad I decided to try a couple.
