A variance in muzzle velocity should have little or no effect on lateral [side-to-side] point of impact.
If velocity variance has any effect on POI at all, it will most likely show up in vertical POI variance. However, in the case of a handgun at 25 yards, POI variances due solely to velocity variances are probably not even measurable.
Some of the factors which affect variations in muzzle velocity are
variations in:
>primer brand [unless all ammo is loaded w/same primer batch]
>primer flash hole diameter
>cartridge case headstamps [different manufacturers]
>case cleaning
>bullet weights [weigh your bullets to 0.1gr and see what you find]
>bullet seating depth
>powder charge [unless each load is weighed to 0.1gr]
>bullet seating depth
>bullet crimping
>barrel warp under heating
It's almost impossible to separate the effect of these different variables on velocity variance.
Now, a 30ft/second SD for muzzle velocity means that the entire population of your shots experiences a variance range of 180ft/second.
Example: Assume standard distribution and an average MV of 1000ft/sec. Then the velocity range for all shots would be 910-1090ft/sec, with an occasional flyer above or below this range.
Which is a pretty hefty variation, but probably other factors [trigger pull, etc.] would have more effect on POI.
Final Analysis: The primary purpose of a handgun is personal protection. What shows on your target will work for you. Just fine.
