Accuracy and consistency should be the over-riding goal.
After loading hundreds of combinations with the 9mm seeking a minimal and accurate load, I've found that mid-weight bullets, and medium burning pistol powders work the best in 9mm.
The issue with the 9mm is that recoil is what cycles the action, so reducing recoil affects firearm reliability. Often with the 9mm, simply reducing the recoil spring strength dosen't do the job.
I've four different S&W 9's. Three are Performance Ctr. guns; a 5906PC (4"bbl), and two PPC-9's, and a "production" Super-9 with three bbls.- 9mm Para, 9x21, and .356TSW. I've also had counting a .38Super 4 "1911" 9's, and several other 9's. (CZ, Excam-BTA, Star modB, Glock-17, ect.)
I have lightened the recoil springs on the Smith 4" progressively till they no longer would cycle the action, but the minimal loads for reliable function essentially didn't change. I've also tried bullets from 90gr to 160gr. The key element was slide INERTIA. The mass of the slide is factored as is hammer spring tension, as well as recoil spring tension in designing the pistol's manufactured parameters. Lesser factors are such as the friction of the top cartridge in the magazine with a full magazine.
So, in the final analysis, I find by best loads for "plinking", and practice is essentially that of a "standard" velocity 9mm.
For the above load, I use a cast 122gr TC over 4.3gr of WSF, for about 1,100fps. This load is totally reliable and extreamly accurate, though with the cast slugs, occasionally I'll get an unexplained flyer at 50yds.
For match shooting, I use the Remington 115gr JHP over 5.3gr of WSF for 1,180fps from 4" gun, 1,220 from two 5" guns, and about 1,250 from 6" gun. This load is about the minimum that will cycle the massive slide of the 6" gun. These guns were designed by S&W to function and produce optimum accuracy with the standard 115gr loads with which they are tested with at the factory. Minimum acceptance standard is 1" at 25yds for 5 shots. All three greatly exceeded this minimum, one at under 1/2". All three PC guns easily do 1" at 25yds with both stated loads.
I suggest you use a 115-124gr bullet with perhaps N330, or N340, for 1,100 to 1,150fps. This will be the minimal recoil that will give reliable function in most 9mm handguns. Recoil is minimal as it is. Anything less, and you might as well be using a .22rf.
You didn't state what firearm you are using, but I would suggest a .22lr conversion kit if they are available. Often with service grade guns these give superior accuracy to the Center Fire setup.
) for the lightest load that will cycle properly.
