You are asking if this is a good barrel lathe. You need some data to decide that.
Most important, how far is it through the headstock from the front of the 4J chuck to the back of the spindle? Add two inches to that and that is the shortest barrel it will easily chamber through the headstock.
In general, with a few exceptions (the South Bend Heavy 10 being one), big old american iron is not the best choice for gunsmithing. The spindle holes are small for the size of the lathe, the headstocks are long, the spindle speeds are too slow, and they are more difficult to cut metric threads with (for chambering european rifles that have metric barrel tenon threads).
If you are serious about getting a lathe for hobby gunsmithing go look at the small Grizzly or a similar 12"x36" import (but not one from Harbor Freight). They will let you put the barrel through the headstock with is by far the best way to chamber and crown rifles. It can be done in a steady rest, I've done it both ways, but it's not nearly as convenient as thorugh the headstock like this:
The Grizzley has the headstock cross drilled for rear centering bolts but it is a piece of cake to drill other similar lathes like I did to mine:
As others have said, tooling is the real cost of the lathe. The new imports come with all the chucks, backplates, and centers (though probably not a live center) you will need and frequently a quickchange tool post. That tooling is worth a thousand bux if it has to be purchased for an old lathe.
If you want to repair farm machinery, the big old iron is the clear choice, but gunsmithing where the cuts are light and flexability is at a premium, the 12x36 imports are better.
Fitch