empty cases for trigger work

Read an article on how a person needs to balance an empty case on the top strap while practicing their trigger pull. 

With loyal 629 in DA its really easy.   IN DA, slow or medium, the case flies off. But when placed on the barrel serrations,,, it just stays their.

is that a result of big heavy gun, crappy long trigger pull,,  when i do it, i only notice a muscle moving in my inner elbow.

If you dry fire against a blank white wall and watch your sights, you do not need the balanced case on your pistol/revolver. If you spend 80-85% of the time on a blank wall and 10-15% aiming at a target you will learn how to squeeze your trigger.
Pretty easy remaining still with SA pull. DA pull requires constant very minor corrections to keep sights lined up (sight alignment) and for sight picture. I have a very good DA trigger pull, but am constantly working to keep everything lined up. I probably cannot keep a cartridge case on top of my revolver when executing the shot off hand. But it will be a good shot.
There are many myths as I like to call them about marksmanship. The empty cartridge case is one of them. Your focus on keeping the case balanced (not falling) is taking away from your other fundamentals. When I was in basic training we did an exercise in two man teams. One shooter in the prone and teammate put a washer on the M16 barrel as you dry fired. You could focus on position and trigger pull because washer was not visible and you were already in position. Pull trigger and see if washer stayed in place. Then switch with teammate. I think it had more value because you had assistance and it wasn’t blocking your view. 
Jon

Eonscago when I was a teenager, our coach used to put a 22 on our front sights and stated that we had to be able to dry fire and not disturb the case to cause it to fall.  I never could do that with my m1922 Springfield 22, the striker was just too violent.

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Seems distracting! When hammer falls, you can see if sights moved, after all, that's what you're supposed to be looking at!

its not about making sure the sights stay lined up.. its about creating a consistent methodology in how you hold your hand and pull your finger.. 

if you have wild movements, say you like to pull the gun hand to the right as yo upull, the case will fall that way.. same if you roll left the case falls that way. 

when we had to do our demonstration of a firing position in basic, my instructor was an army DS  who had done 4 years as a marine before switching to army.. he almost started playing with himself from happiness when he did my testing.