Originally Posted by cadmike
I think if you want 45 ACP performance, then shoot 45 ACP.
One thing that is missing in the .45 is capacity. It's generally accepted that 6 rounds out of a revolver or 8 rounds out of an ACP wasn't enough 'firepower'. I can get 17 9mm cartridges in my third gen 9mm. But you're right, if they can make a Shield .45, they can make a plastic .45 full size that would save some weight to carry.
I think (to me at least) that maximizing the effectiveness of the 9mm is worth running down. The 'philosophies' that we hear about bullet mass/velocity MAY favor the heavy, slow round, since it works so well in the .45. If a little can be added to the weight and expanded size of the 9mm and it REALLY makes a difference over shooting 115 gr, 124 or 157 grain ammo out of a 9mm, I'd like to know it.