FALCO holsters are fitted to a particular firearm make / model and will have a high degree of retention. The initial fit can be very tight and would require some stretching of the leather to allow for a smooth draw but still sufficient retention. It needs a break in period. As leather is a natural, porous material that absorbs moisture, it can happen that it would tighten in the drying stages. Falco color, treat and oil the leather in the holster crafting process and can never predict how much moisture the particular piece of leather would absorb.
So the holster may be stiff and tight at first but that is quite normal. It would only need to be broken in. All you need is a plastic grocery bag, your holster and your gun. Before you begin the break-in procedure make sure to loosen up any re-tension screws if your holster has them.
Wrap your gun in the grocery plastic bag, leaving the handle exposed for a firm grip and slide the gun into the holster. Do not worry to push the gun in really hard. Leave it holstered like this overnight, maybe couple of days. Then draw the gun out, take the plastic bag off and try re-holstering it. It should loosen up enough for you to insert the gun more freely. If you still find it too tight, please repeat the process with the plastic grocery bag until you are happy with the result.
As far as the retention strap – thumb break goes, if you find it difficult to close with the holstered weapon, please follow these instructions. Use Isopropyl Alcohol (Rubbing Alcohol) available in each grocery store or pharmacy. Soak inner surface of thumb break strap generously then hold on to the strap and pull on it really hard while pushing the gun into the holster. Keep on pulling that strap over and over until it stretches just enough to snap close. Leave it with the gun inside overnight. This would break in the retention strap.