AR-7 man here. This model is probably as close to maintenance free as they come. Most of the exterior surfaces are aluminum, and the rest are plastic. Providing you are using decent ammo, there is no necessity to scrub the bore, certainly not on a routine basis.

The action is accessible by unscrewing one screw holding a side plate. Working on it is fairly simple and straightforward, and not likely to be required.

With any firearm, one should have basic tools for maintenance and repair and basic lubricants. Most of these will also be necessary for the proper maintenance of other items in your inventory as well.

I often use my AR-7 as a single shot; in survival mode,I am sure that would be especially common in order not to squander ammo. Loading individual rounds means one could utilize 22 shorts or CB caps (sparingly, in order not to damage the chamber) and they would be pretty quiet.