Hi,
I am fortunate to own and shoot all Uberti Smith and Wesson reproduction Top-Break, Model No. 3, large bore revolvers. Therefore I am always looking for leather for them. "Old West" leather.
What follows is lengthy.
I am not a leather expert, I have learned the following by being cheap and inexperienced. But it has worked well for me.
First off measure the dimensions of you revolver at the front of the frame from top of the top strap to bottom of the frame in front of the trigger-guard. If those dimensions match (or closely match) the same measurements of a Schofield (repro or original) then a "Schofield" holster might fit your revolver. It appears your barrel length might be 6 inches? 5.5 inches? therefore search for holster that will accommodate that length. Some holsters with an "open-end" shaft will allow a barrel to stick out a bit and acceptable in "Old West" holster standards.
Your trigger-guard may be larger than a Schofield or other S&W Top-Break and may cause fit problems.
If you go to Ebay and type in "Schofield Holster" you will find some Slim-Jim, carved holsters for a 7 inch Schofield by a seller named "tonyu!" He is reliable and his leather is good. It is an open-end.
Also go to "heritage manufacturing inc" and they have a selection of inexpensive holsters that might accomodate your "sixgun". Look for their "big Bore" holsters. The crossdraw 1089LH-4 and 1089LH-7 might fit you gun. Also their 1080BBLH-4 and 1080BBLH-7 may also fit. Lastly is the 1091BBLH-4 and 1091BBLH-7 may fit. Currently their stock is mostly left-handers but haunt the sight and they may soon have right handers in stock. These holsters are actually made by Hunter Leather but sell cheaper than Hunter leather. The "Mexican Loop" styles are open-end.
Next option is "America's Gun Store" the "Sonoran Holster" in its Colt or Ruger 4 3/4...4 5/8 barrel and 7 1/2 inch barrel will accept a Uberti Top Break. It is open-end.
Cimarron Firearms sells gunleather and they have Schofield holsters. They are open-end
There is also El Paso Saddlery. Expensive, but excellent.
Old West Reproductions will make you and excellent holster. He is a fine person to do business with.
When you find a holster. If it is a bit tight, too tight, the pistol "almost fits" but sticks up a little high...this is what I do. I take the revolver and liberally spray it ALL over...except anywhere near the grips...(or remove them) with a spray preservative like WD-40, Break Free, Rem-Oil. Just hose it down. Then I wrap it TWICE with "Glad Wrap" (any plastic food wrap). I fit, fold, cram, whatever to get tight fit to the revolver in its frame, "nooks-and-crannies". Then wet the outside of the holster liberally with rubbing alcohol. Then cram the revolver into the holster until it fits as desired. Then let it sit for several days until the leather dries well. Take everything "apart" and the excessive "fit" caused by the wrap makes for a good holster fit. The wrap is also necessary to help protect the revolver from corrosion, don't rely on the protective coating alone. Water can be used in lieu of the alcohol but it has a longer drying time. "Sure-er" fitting is done by wetting the interior of the holster with alcohol or water as well as the outside can also be done. But takes longer to dry in the interior. Aggressive fitting can be done by tossing the entire holster into a bucket of water and letting it soak until it is thoroughly wetted inside and out. BUT...the less you "wet" the leather the less chance you have of altering the color. The less chance of removing the dye.
Also the cheaper holsters will have a rough inside leather finish that will rub off the blueing. I take "Vaquero Cream" or "Sno-Seal" and literally coat the interior of the holster and let it set or "dry out" and this slicks up the inside.
Regards.