Thanks a lot people, I now understand how I can repair my Varmint ! However, I am starting to think I really need to get the sniper riffle (Varmint having some difficulty killing stuff).
It's your Skill level and Perks ... not the Varmint rifle.
I have Gun Skill of 100, Sneak Skill of 100, Luck 10, and various Critical Hit Perks and I can take down a deathclaw with my modded Varmint rifle in VATS or not in VATS. Granted with the GOBI Sniper rifle I can do a one-shot kill on a deathclaw ... but ... I enjoy perching myself correctly and taking down a deathclaw in a dozen or so long ranged sniper shots with my silenced, scoped, Varmint rifle while he can't figure out where those shots are coming from .
B)