Unitizing? Nobody has offered a welder (portable TIG/MIG) on a rig service truck yet. BUT , we can shim and tighten up your already pretty tight gas cylinder assembly. Trust me, my old USGI M14's with their battle dimension'ed gas cylinder assemblies shook & sounded like a Christmas ornament.
No joking! These recent (last 10 years) Norc and Poly M14's are a super improvement. The Kommunist Zhinese high school shop class got THAT right ! 