As I have posted in the shotgun section, I'm interested in developing a tackdriver slug gun just for the novelty and fun of it. I have a limited distance range, and prefer the sluggun idea for my fun and experimentation. I've never scoped a sluggun before though. Is eye relief and recoil resistance on the Leupold Rifleman series enough for this type application?

I just built one myself on an 870. I went with the Leupold VXII 1-4x. It has an eye relief of 3.8 to 4.3 inches.
The Rifleman has its lowest power a 2-7 with eye relief of 3.7 to 4.2 inches, so for eye relief there is not much difference. However, if you use a catilever barrel like those for an 870, you may find you have trouble getting the scope back far enough with a belled objective, or to get it back far enough, you need to use higher than normal rings. For a slug gun, you will not need anywhere near that kind of power, and with the straight tube of the 1-4 you will not only have all the power you will ever need, but you can also use low rings and still be able to get the scope back where you want it.

Toolmaker........I have 2 Leupold "shotgun scopes" on our 12 gauges and they are great in the woods and low light too.
You won't lose a turkey's head in the tangles of vines and branches at low light. The Recticules are very heavy and thick!
Not a scope for target shooting of a centerfire rifle.

However, they make a great scope for a big bore or shotgun where range is a Max of 150 yards or so. They also take a lot of punishment, as this big bore I have deals out 75 pounds of felt recoil to the body. The Leupold shotgun scope I have on it is a 2 x 7 power and it's been on the rifle for the last 4 years now and no complaints yet.