I would buy the rifle seperate for the $99.00 from Bass Pro. Then decide first off if you want a scope and second spend a little more and get the scope you want. Many times the scopes that come with the kits are not of the best quality. Your better off to save a little more and get something like a Bushnell Banner Dusk to Dawn with extended eye relief.

As for caliber get the .50 caliber. Down the road if you want to take some hunting trips for big game, some states will not allow a .45 caliber rifle. Also there is nothing a .45 caliber can do that a .50 caliber can not do also or better. Right now the bullet selection for the .50 caliber and sabot selection are much better. Also there are a bigger range of conicals and molds for the .50 caliber if you should decide you might someday want to get into making you own stuff.

If you have an extra $50.00 look into the H&R Sidekick. They are the same style, open breech rifle. I have read some excellent range reports on the rifle and those that have them seem to be very pleased with them. Plus they are an established company. The Beartooth Magnum has only been around a couple of years I think.... Sometimes spending a little more for a company that will provide customer service and support is a good investment.....