There's some guy out there who would pay a fair price for your .223 #3. Take the money and buy a #1 in 45-70, if that's what you want. I've put a #3 in 30-40 in #1 wood...call it a #2...with minimal effort and the result is a nice looking rifle. IMO, any caliber you fancy available in a #1, you will be ahead selling your #3 and buying a #1. Conversely, should you want a non available caliber, modifying your #3 starts to make sense. I'm in process of making a 505 Gibbs #1...my idea of something "neat".

Otto