You need a blackpowder rifle...one of the modern ones for hunting and an old style, for blackpowder shoots at the range.
Buy a Sharps Carbine, or a Sharps rifle for long range shoots.
Besides an AR-15...I would buy an AK-47 or a AK-74.
A Stirling Carbine...in 9mm, would round out the bill.
Here's hoping...that you have a safe big enough for them all.