You will probably get a different answer from everyone here. There are a lot of quality guns out there now . I'm not a professional but I have hunted with blackpowder for 30 years and have quite a variety of muzzleloaders. I would say a Thompson Center Omega in 50 cal.. They are quality guns that shoot well at an affordable price.Blackhorn 209 is the newest powder but I haven't tried it yet. I still shoot triple 7. For bullets I would use the 250 grain Shockwave easyglide. For a scope the Nikon Omega . Stay away from the Traditions scope as I just had a new one bust apart inside. I'm sure you will get all kind of answers . Second choice for a gun after the T/C would be a Remington Genesis.
The decision is always the hardest part Good luck
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