These were on my mind,still look like the lore Service rifle,but with some small enhancements
http://www.nexusmods.com/newvegas/mods/40361/?
http://www.nexusmods.com/newvegas/mods/44609/?
Also there's an opioonal replacer for the Service rifle to a decent looking M16a something (don't remember anymore)
http://www.nexusmods.com/newvegas/mods/42970/?
Oh and if you know how to use the Geck,you can replace it to anything you want,but that's up to you