The hard truth on this one is that there is no free lunch in life in general and particularly where double rifles are concerned.

As Express has pointed out, skilled smiths do exist, but even at average and reasonable labor rates, the work involved will drive the price of the Bailkal up to where the cost might likely exceed the cost of a good new Merkel, etc..... And at the end of the day, it'll still be a Baikal that may be worth a thousand bucks.

For an entry level rifle that gets one into the double rifle game, buy a stock Baikal and enjoy it the way it is with minimal mods or work done to it in either .30-06 or .45-70 depending upon whether you like it small and fast or big and slow...... The caliber equation is really not all that much more cosmic than that and other than romance, there is little more to be gained in the caliber selection process.

This is not the answer most would want to hear that have their sights set on this type of project as driven by looking for a way around the entry fee of a good working double but it is reality. The one exception may be for the skilled gunsmith that can do it themselves, but even then, if they're spending time on this project for themselves they are not clocking any billable hours or making money, so even to them there is a significant cost that may have better been spent going out and buying that new Merkel for themselves.

From a financial perspective, if one doesn't want to use the stock Baikal, one might be best served waiting it out, saving longer and buying a good used name brand double in a caliber with similar attributes to the desired caliber (assuming one can't find one in the primary caliber of choice). In the long run, these types of name brand double rifles will likely appreciate in value over time and would be a better bet financially.

As a closing thought, please don't be offended by my opinion. I do have a proven track record of making small fortunes. I have found that if I start with a large fortune, I have quite the knack of turning it into a small fortune and I have the documented track record to prove it!!!!