I'm pretty skilled at making parts by hand.
You can use the spring from the old barrel latch if you remove it carefully its just pinned in place.
If you aren't up to making a new latch you can use a punch to upset the metal on each side ant the rear of the latch where it contacts the barrel or at the center of the front where it contacts the inside of the Cylinder pin/arbor slot.
Use the punch on both upper and lower surfaces. If the latch is not hard, and few of the replica latches are hard, then the first time you tap it home it will size itself and flatten the bulged surfaces. After firing a few full power loads it will set itself properly and won't be dificult to remove and replace.
Also many replica guns have ill fitting latches that bind at the rounded corners of the slot and dont even contact the place where they are supposed to in the center of the pin.
Those will appear to be tight fitting but when fired the gap opens up with each shot. When they wear in they are loose as a goose.
The inside surfaces of the barrel lug where it faces the frame are often left rough with deep machining marks. Usually if you just carefully file these flat and smooth you'll have already removed several thousadths of an inch, same goes for the mating surface of the receiver though its difficult to do anything about that unless you want to pull and replace the pins. I've done that also, not hard for me but not something you want to try unless you are confident of your skills.
I could show you much easier than I can tell you.
Invest in a good selection of jewelers files.
PS
Some cheaper replicas have oversized openings in the barrel lug, or undersized arbors, If the cylinder arbor is a loose fit then tightening the latch cocks the barrel upwards and the cylinder binds on the top.
If the fit is very loose you can shim it with either a very thin brass shim or a piece cut from an aluminum piepan.
I just make a new cylinder pin sized to fit properly.