One of the big differences between Uberti & Beretta or Ruger is the transfer bar.
The original Colts, like the Ubertis, have a hammer mounted firing pin.
Load one, skip one, load four.
That leaves the chamber under the firing pin open.
Beretta, Ruger & others use a transfer bar to engage the firing pin.
MUCH less chance of accidental discharge - but also less authentic.