The .440 inch marked balls you bought are for a .45-caliber muzzleloading rifle. The cloth patch around the ball makes up the difference in the bore.
A salesman either sold you the wrong balls, or you didn't make it clear that you wanted balls for a .44-caliber cap and ball revolver.
I would not use those .448 inch (by your measure) balls in any .44 cap and ball. They are entirely too small to ensure a good seal in the chamber. Undersized balls like this can cause multiple ignition. Accuracy will likely be lousy.
I'd suggest you use .454 inch balls. See my post on, "How to properly use a cap and ball sixgun."
I don't like the .451 inch balls that the books suggest; I haven't found them as accurate. The slightly larger ball creates a wider ring around the ball, after it's rammed home, for the rifling to grip.
You may also use .457 inch balls, but only if you get a good deal on them. I picked up a few boxes of Speer .457 inch balls a few years ago from a sporting goods shop going out of business. They work fine in my Uberti Remington 58 and Pietta Colt 60. They seat well, without undue force.
The .457 inch balls also make wonderful multi-ball loads in my .45-70 Marlin. But that's another story.
But .454 inch balls are best overall for .44 caliber cap and ball revolvers.
Use .380 inch balls, if you can find them, in the .36 calibers. They seal better, provide a wider driving band for the rifling to grip, and are more accurate in my experience.