Gunsmithing what to fill void between sxs barrels with?

[GrantA]

I just got a new-to-me Stevens 311 Series H which has had the barrels cut to 20". The cut looks good, but there's an open void between the barrels and I need to put something on the end to keep rust away (raw steel where cut, has just been kept oiled and in a safe w/ dehumidifier). Should I use something like devcon or JB weld and then what should I use as a coating?
What say the experts?

Thanks!
Grant

 

[WhiteDingo]

All sorts of things you could use to fill it. I've seen a number of guns that have a steel-putty epoxy mashed in the filed/sanded flush; they end up looking almost like a solder fill. Or, if you want to do it right, cut and fit a small piece of steel slightly undersized, then soft solder it into the end and file flush.
The barrels on 311s are silver soldered so you could even use a higher temp soft solder like Hi-force 44 to solder it in.