One of the first tips against jumpy meter which I read here was to delay the release for a few seconds.
Me thinks it's not what you do but what you do not: release and shoot soon.
Have a look at the CPU load in the task manager. Shooting with high CPU load is like shooting with high heart rate: more probable jumpy meter.
When a shot is loaded, new picture and all, there is a lot of CPU action. When you change clubs or move the aimer, there is CPU action. And, it takes some time to cease - waggle or hold time, or, waiting time.
To raise the club causes visible CPU load only on PCs with low memory or aged systems, not on state-of-the-art machines. Thus you can wait or waggle - it will help most of the time. Sometimes, especially in MP games, it takes forever, then the general clock can be an enemy. Auto-release of the meter can also happen.