>>63838763
Service pistols by necessity can only really have so much velocity for practical reasons, because they're pistols with pistol length barrels, thus they need to make up the difference best they can with a larger and heavier bullet.
In my opinion, a 124gr 9mm going ~1200fps is really pretty adequate in terms of weight and speed particularly with a good bullet, though I can see why some would want a larger and heavier projectile like with .45 (230gr at 850fps) or something like that.
The smallest projectile I would be comfortable with for a sidearm would be 7.62mm, and that's if you hotrod it, ergo 7.62mm Tokarev, commonly an 85gr projectile going ~1400fps but maybe as high as ~1500fps.
A rifle easily achieves a LOT more speed, so 5.56mm having just a 55gr bullet is ok, because it rockets that fucker out to around 3000fps. For pistols, this diameter of bullet doesn't cut it for me, a 40gr 5.7mm can do 1700fps from a pistol, which really isn't enough speed to make that lightweight bullet really worthwhile to me. At least for combat purposes.
If you want to try to get something that gives you even just comparable energy to a 5.56mm rifle but in a pistol, you need not just a LOT of speed, but also a heavier bullet than that because again, barrel length, thus you're looking at a Dirty Harry style Magnum handgun like .44 Magnum (240gr doing 1450fps), or .45 WinMag (230gr doing 1600fps). Naturally, you pay for that with much more recoil and much more noise and blast, and there's no high capacity options for this kind of handgun, at least that I know of.
Just for the fun of it (to me anyway), if you wanted projectile weight comparable to the .44 and .45, but with projectile speed like the 5.56mm, you would be looking at a big bad Magnum hunting rifle caliber like .30 Nosler, which drives a 210gr .308 caliber projectile to 3000fps, a true Grizzly Bear gun.
