Not without a DETAILED description of ALL markings, condition, etc..
You need an antique firearm appraiser or an auction house to help you
The 7-sided bore black powder rifle with JPO markings is likely attributed to Joseph P. O'Neill, a notable firearms maker known for his innovative designs in the 19th century. His work often included unique features and markings, distinguishing his rifles in the market. If you're seeking more specific details about a particular rifle or its history, additional context would be helpful.
0.75 caliber smooth bore black powder flintlock muskets.Musket bayonets.Kentucky hunting black powder flintlock rifles.Various knives.Tomahawks.Sailing warships.Cannons.etc.
bore
A musket is smooth bored, like a shotgun's bore. A rifle has rifling inside the bore (grooves).
You will need to include the model number if it can be viewed on the side lock,if not plese describe the barrel lenght,how many bands around the barrel,and caliber by measuring the bore to help identify your old military musket,flintlock.
The bore is rifled so as to put a spin on the bullet. This spinning gives a greater accuracy to the bullet, especially over that of a smooth bore.
Almost any Combination BB & Pellet rifle is smooth bore. BB rifles usually are Smoothe bore. The Crosman model 760 is such a rifle and can be purchased at most sportingood stores. Look at the packaging and it will say Smooth bore. Smooth bore barrels are less accurate than rifled bore barrels. Cabelas, Basspro, Big5 and Sports Authority usually carry them.
No
Caliber
Rifled, unless you have one marked "shot only"
The bore diameter of a 250-3000 savage is .257