Rifle Scopes Leupold IMS

[greenduck]

I am looking at picking up the Leupold Mark 2 or 4 IMS but I can't really find the information I need. I currently have an older Leupold vx-1 that I would like to be able to use on a couple different rifles until I can save up for a new optic. Obviously I will have to rezero each time I move it but it would be nice to return as close to zero as possible.
I have checked Leupold's site, Google images, and several online retailers to see how they work. From what I can tell they are all a two part system. The rings are a single unit that slide into the base which then clamps to the picitanny rail with two thumb screws. The part that I can't figure out is if the clamping system that holds the base to rail is also used to hold the rings to the base. If that's the case it seems that moving between rifle would necessitate adjusting eye relief. Or, am I completely wrong and these are one piece units similar to the Burris pepr?
Unfortunately I haven't seen any of the IMS in any of my local shops so hopefully someone here has experience with these mounts and can shed some light for me.
I know there are probably better quick release options like a LaRue but I can get a good deal on Leupold.

 

[SomeOtherGuy]

The Mark 2 and Mark 4 IMS mounts are different. The Mark 2 is basically like a Burris PEPR or other common one-piece mounts, where the lower ring halves are integral with the base. The base is clamped with a little clamping bar and two screws, and upper ring halves attach to the top. The Mark 4 IMS is multiple pieces like what you are describing, but as far as I know (I don't own one) the rail clamp and ring clamps work independently.

I have a Mark 2 IMS in use and I think it's pretty good. Much like a PEPR but a little more nicely finished, and I think it's made in the USA.

 

[greenduck]

Thanks for the info.

Leupold got back to me today and basically reiterated what you said.
"The Mark 4 IMS is the only system of the two that uses a ring insert. The ring insert is slide into place and tighened to the base using the supplied screws.

The Mark 2 IMS is a one piece machined base."

Now I just want to see if it would be usable with their QRW bases. I'm guessing the cross slots won't line up.