Nope, it's illegal.
To the best of my knowledge unless you are a convicted felon you can own a black powder gun.
Upon installing the cylinder you have, according to the law (or at least the ATF), manufactured a firearm. So the simple answer is "No". It is not legal for a felon to own a firearm (gun) and once you install a conversion cylinder that pistol is no longer a "non-gun" black powder pistol.
No. There is no state were a felon may own any firearm.
In the U.S. a convicted felon may not own or posses a gun.
No
No. A felon in any state is not allowed to possess any type of gun, regardless of if it is loaded or if ammo is available.
ask your state Attorny General
Never. A felon has lost the right to possess a gun.
It depends on what the felony was, but in most cases, yes. This has to do with the second amendment.
You need to talk to a lawyer to be sure.
It is always best to consult a lawyer that is familiar with the local gun laws, or even the local prosecutor.
This question is best answered by local law enforcement