RE: 6.5x55 Swedish mauser
Again, what Slamfire said.
Your husky if in its original military configuration is probably woth $300+ right now, mainly because its a collectors item. If you drill it an tap it, its value as a collector will diminish greatly.
A couple weeks ago I was at the range and a guy had his Swedish model M94 with him. This is only about the 4th one I've ever seen. He said it bought it for about $50 a few decades ago and kind of laughed as he said that he wished he knew better before he mounted the scope on it.
One of those in pristine condition can sell for $700-800 right now.