I have a Don Hume in the waistband holster that the snaps have weakened throughout the years. They still snap, but they've loosened a bit. Is there any way to "tighten" the snaps?
Yes, old snaps can often be tightened up,,,
I've done it many times.
Place the ring side of the loose snap on a flat metal surface,,,
Protect the other side with a cloth or scrap of leather,,,
Tap the snap with a mallet to flatten the ring a bit.
Don't get carried away or you'll flatten it too much,,,
It doesn't take much at all.