I am a bit north of you in the Lehigh Valley. I don't have experience with it, but my father used Gary's Guns ((610) 759-7651) in Nazareth PA. He did good work.
Another option is Dale from Big Sky Guns. He used to be in the Montana West building on Rte 309 in Coopersburg, but I think he is working out of his out. The number I had for him in my mobile phone is (267) 347-4495.