If the reason you want a low tone is to not bug everyone at the range or home, check out the CED 8000, it does everything the 7000 does except stop watch, it comes with ear buds and is totally silent
I'm left handed and think using my trigger finger is the only way to go, the only problem I've had was with a double under cut grip, my grip was so high that i started dumping mags accidentally. went back to the original grip and cured that problem
I had this same problem with my Edge, turned out it was the mag spring, not enough tension.
The slide would strip a round and at the same time pull the round below forward enough so that the nose was
engaging the slide stop. Replaced the spring and solved the problem
This past Wed. I was running a guy at practice and same thing, bang, bang, bang, click, no pop, and I see a bullit
fall out the barrel, he racked the slide but I yelled STOP. Just had to check and see if I saw what I saw
My worst day was 22 yrs ago,had a bad accident and cut off my thumb and the tip of my index finger right at the knuckle
good thing it was my weak hand. Hope I never have another one of those days