Quote Originally Posted by hddscan View Post
I've heard both variants in Vologda region
With цепочка considered grammatically correct in that region.
Цепочка is grammatically correct in all regions.

I can guess that Western part of ex-USSR, including Western part of Russia uses both variants.
No, it is not the question of East and West at all. I think цепочка is used by less educated people, it's one of the reason. Second, it's like saying "красенькие" instead of "красненькие", some special style of language, but not a dialect. It's like "if it's just an uninteresting chain, it's a цепочка, but if it's a oh-so-lovely chain I'm dreaming of / I see on you, then it's a цепочка".