I crafted a snap cap for my Model 41 for next to nothing and have used it for hundreds of "shots." The plans are freely available at http://www.flat5.net/trashcansnapcap.html and make use of a commonly available trash can as the only source of material, hence the name, Trash Can Snap Cap.
I have been surprised to find out, and I'm maybe even a little embarassed to admit, how important arm, and especially shoulder, strength is in all this. Seems obvious to me now but ...
I keep a small handweight (3 lb. but am now thinking 5 lb. would be better) at my work desk and try to do several "reps" of simply holding it at arm's length (as if I were holding my S&W 41) for several minutes, always trying for a few seconds longer, and then longer, and then longer. (Yes, I hold as long as I can each time, not just for a predetermined interval.) A few simple, up and down (with straight elbow) swings at the beginning and again at the end of each session feel good, too. When away from my desk, I've used dictionaries, soft drinks in fast-food restaurants and even my wallet but that's usually an easy one, particularly after a trip to the gun store.
After several days of that exercise, I found my hold time at the range was MUCH better. With the extra strength and, more importantly, with the extra stamina that comes with it, I could afford to wait for the wobble to decrease and still have time to THEN take a deep breath, let out about half, hold it, and make a final check of sight alignment before starting that slow, straight-back squeeze.
