"I have to add that I know that my first mistake was purchasing without knowing, but if the shop gave a ****, they would have told me that buying this combination was not advisable/recommended/for amateurs... I was following their lead. And like aways thanks for the straightening out and the good information."
Loading 158/160 grain lead bullets in 9mm is really a balancing act, and an act IMO to be taken on later when more experience has been gained... Shame the shop did not have this knowledge in your situation.
I will say however, loading 158 grain lead SWC bullets in 9mm is very doable, and actually pretty fun in my experience do so. The hard part is finding a bullet with the right dimensions for your particular pistol if the attempt is made. For me this means using pistols with long leades, and generally large-ish chambers and groove diameters. Having these conditions will allow you to seat the bullet out as far as practical, still minding max allowable OAL's, without having the shank/wadcutter edge hit the rifling on chambering.
Since both my 9mm pistols have long leades, seemingly generous chambers, and groove diameters of .357"+, finding the proper OAL for my pistols with .358" Speer LSWC's, and Hornady LSWC's was no big deal at all. Chambering is easy as any other properly assembled round. As for propellant choice; no doubt Bullseye could safely be used to make at least .38 Special type std velocity ammo (725-750 fps), I used a propellant with published data for the initial application. I contacted Hodgdon a few yeas back, asking for HS-5 data for a new caliber I was trying out with a can I bought over 25 years ago, and included in this data was 160 grain lead 9mm loads using HS-5, HS-6, Trap 100, and HP-38.
Wanting to start using a propellant on the "slowest" side listed and rather dense, I used HS-6 at 3/10's grain under the max charge listed, and got just over a measured 900fps from my Beretta M9. Function was perfect, recoil mild, with the impulse feeling almost in slow-motion. The area on the cases that are not chamber supported showed not a hint of pressure worries, and I have little doubt in my particular situation of variables, I could have gone to the full max rated charge weight. After this testing, I did develop some 158 grain lead bullet loads using Unique that achieved velocities about 10 fps faster, with the same great results. As a final tip, it is paramount that the actual bullet to be used, be weighed to make sure it is actually 160 grains!... Bullets cast using a "soft" alloy could be considerably heavier than intended, and considering the work at hand, the cartridge and variables concerned, pressures would rise at a much different rate than say using 115 grain RN FMJ's at 1.169" and working up charges of Unique.
Lastly, my philosophy and joy concerning reloading is doing what I can and want to achieve within the reasonable bounds of safety, and level of experience; not "why can't I" or "why do it"... Now I know by actual prudent testing, that if I wish to have the equivalent of a 20 shot "FBI load" semi auto, it's a simple matter of heading to my reloading bench and cranking them out.