As stated earlier 44 c&b is .45cal.
In the old black powder days folks measured things all kinds of differently. Some of it is still labeled weird like how .38 special and such isn't .38cal its actually .357cal.
In those days, the nominal caliber was the diameter of the bore before the rifling grooves were cut. A .44 inch bore with grooves .006 deep made the groove diameter .452.
So, whether it's a ".44" or a ".45" depends on what you are measuring.
If you measured land to land instead of groove to groove, a Colt .45 actually is a .44 caliber gun.
Why the .38 Special is really a .357 and the .44 Special is really a .429 is a long story that involves a change over from heeled bullets to inside the case bullets.
For what it's worth, MODERN revolvers have been blown up with reloading mistakes with results closely resembling that of the Remington in the link.