Typically gun steel is an A723 type steel. Check the characteristics of that steel, but the only thing I could think to be careful of is embrittlement after welding.
Jim
Pipefitter/Weldor out of Local 396
Millermatic 252
Dynasty 200DX
Maxstar 150 STL
Spoolmate 100
Hypertherm Powermax 85
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Pipefitter/Weldor out of Local 396
Millermatic 252
Dynasty 200DX
Maxstar 150 STL
Spoolmate 100
Hypertherm Powermax 85
Miller Digital Elite
JD2 Model 32 Bender
Emerson 7120 Horizontal/Vertical Bandsaw
Oxy-Gas Torch outfit
Generac XP8000E Generator
tig is the process of choice for quite a few modern gunsmiths, the best reason i can see for this is the wide variety of filler/ fusion metals and the adjustability of the amperage (heat) put into the metal, this is especially important for hardened and case-hardened steels.....ALWAYS UNLOAD BEFORE WELDING....you probably knew that ,but it never hurts to repeat it.....(for the dumb-asses out there) 
not bad~~O(∩_∩)O
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