Take my advice and DON'T do it! Expensive mistake I made in the past
Loading lever is a nightmare, weak and prone to jumping about and losing the central rammer part with most shots. Small powder capacity so not much room for experimenting and that bloody lock is a nightmare to keep clean and running smoothly.
The 'shotgun' barrel is pants even when the short and oblique strike angle of the hammer has enough grunt to detonate a cap and when it does, think confetti chucker rather than useful appendage. Shot will dent cardboard at 15 yards as there is not enough barrel length to make use of the burn and reach shooting velocity. It's a muzzle loading tube not cartridge firing
Expensive oddity, looks good but how many do you see in the shooting line?