A good Union hut like this one is how you do it... You can either spend 5 hours hunting a spot and come out with a button and a bullet having walked a mile or you can dig out a hut or pit and find all you need in one hole (at least on the union side of things).
It seems like the camp you are hunting was a fairly decent size regiment from all the artifacts you have posted lately. Typically... they set their huts up about 3-6 feet apart from one another but that is not always the case!! they may have had 1 hut site, then a few tents set up, then another hut site so the next hut site could be 20-40 feet away but normally if it was a decent size regiment you will find at least one or two rows of huts setup in Military standards. The smaller regiments did not really set their hut sites up in Military standard line rows.. they typically spaced their huts out more or may have had only 2-3 huts and the rest were just tents.
Photo #1 is of a big regiment camp using military standard lines to form their huts about 3 feet apart (Notice how this camp is setup on a hill side and from are conversation a few weeks ago about huts and you read my post about "Civil War Camps and Hills" they use to LOVE setting their camps up on hillsides).
If you were digging photo #1 camp out all you would have to do is go 3-7 feet and dig the next hut out and repeat the process (add a few more feet due to soil movement/changes over 150 years) the smaller regiment camps...you need to dig more test holes/probe because you may find 1 row of say 8 huts, then the rest were just tents, or they spaced out their huts used only for Officers.. Those are the camps when you are hunting for huts you really have to dig a-lot of test holes to find the hut and depending on the soil and how much has changed around that camp in 150+ years the good signs of a hut or pit like ash/soil color (like the soil color you saw in the fire pit) may be 2 feet down but typically you will get a few good ash & soil indications to lead you to it and of course nails! Anyway dig some test holes in and around this hut a few feet from the one you dug out today and you have a very good chance of finding another hut or a pit.
