I was browsing AIM Surplus and ran across something that gave me a good idea.
The gun is a Semi-Automatic version of the Soviet Guryunov SG43 Belt Fed 7.62x54R Machine Gun.
If you remove the old hitch on the gun's trailer, you could weld on a new one to allow it to be attached to a vehicle using a standard ball hitch. The next required modification would involve removing the wheels and adapting the the axle to accept modern rims. I was thinking something in a 28 to 30 inch BFG All-Terrain on a 15x7 black steel wheel.
The gun rig could be pulled behind a pickup truck, that would be carrying the guns ammo supply. This would allow the gun to be moved around as needed. This mobile heavy gun setup can be called used to support fronts that are getting heavy incoming zombies and require a heavy hitter.
I could also see a similar setup utilizing the 1919 or even the M2 if one was acquired.
EDIT–– Changed Title and have another Idea
Looking at cost issues related the the gun from AIM Surplus, I got to thinking of cheaper, home-built alternatives. I was looking at the above log splitter as a donor body. Periodically, you find old log splitters pop up in the farm+garden, tools, and sometimes in general section on Craigslist. The old Soviet gun on AIM Surplus is just a trailer mounted machine gun with a chicken plate. A resourceful person with some mechanical and welding skills could easily built the same basic rig for much less. You would start by removing the old log splitter setup from its trailer. The next step would involve fabricating and installing the chicken plate on the trailer. Then all that would be left is to fabricate a mount for whatever gun the builder planned to install on the rig. The Soviet setup appear so have a simple hinged setup to allow the gun to sweep up and down.
On the model of log spitter pictured above, it looks like you could simply unbolt the hydralic cylinder and splitter head and leave the beam attached. By mounting the gun high, you could install a box on between the beam and fender, over the axle to the box of ammon currently being fed into the MG if using a belt fed setup.