Yes, seems much wrong with it.
If the barrels are coming closer together with more powder, it needs more yet.
The supplied nipples have holes that are too large at the bottom. You can get good nipples from www.trackofthewolf.com.

The first thing I did with my Kodiak, was to replace the nipples with new ones and reduce the length of the upper conical area. This was to allow the hammers to sit lower. One must be careful as the main springs will punch out the bottom of the lock mortice, if the hammers overtravel. One could also increase the depth of the cup on the hammer nose- somewhat. A little makes a lot of difference.

As the rifles come from Pedersoli - the hammer noses sit higher than the fence, not curling over it as they should. The fence is just that- it is a FENCE to keep cap fragments from entering your big shiny eyeball. Let that sink in.

In my opinion it is a dangerous design they have put out into the public. They DID NOT FOLLOW normal geometry as shown in even CHEAP rifles of the mid 1800's Euro and English design.

Here is a relatively inexpensive single, cap-lock 11 bore shotgun- by H. Wahll.

Here is a "Low Grade" Manton

Here is my 14 bore English Sporting rifle, modern made, & had to sue a Hawken Breech as the shop was out of English Breeches. My late hunting and BP shooting buddy Brad, is holding my rifle. By holding the Ctrl button and repeatedly pushing the + button (or scrolling the mouse button), the picture will become larger for a closer look. Holding the Ctrl button and pushing the (ZERO) 0 button will return your screen to normal size.

The problem wiht the Pedersoli breech/nipple/hammer relationship is the nipple seat is high on the bolster (not enough metal removed before drilling and threading for the nipple. The nipple seas is not in a low enough depression milled on the back surface of the breech plug, as it needs to be.