guns are not normally used in attacks.
that means that you can't justify firing at the attacker much beyond 10 ft. This is proven by the dept of justice, every year, in their Annual Crime Survey. Google for DOJ's home page and check it out.
Also, read Cirillo's book about gunfighting. out of 280 armed robbers, caught red handed in 1968 by the NYPD Stakeout Unit, only 40 did not surrender. They were cornered by the cops, they were going away for life, mostly, for multiple armed robberies, yet they chose to surrender rather than be shot. If you are smart enough to allow the attacker an exit, over 90% will not make you shoot them. So , how often will you have to fire beyond 10 ft, hmm? So why bother with slowfire practice at longer ranges? it's a waste of time and money.
Also, check out the FBI's UNIFORM CRIME REPORT. in it, every year, most gunfights occur at 10 ft or less, and only 5% or so occur beyond 10 yds. since most attacks are not made with guns.,this means that less than 2% of the time, you will fire at more than 10 yds, while most shooting will occur at 6 ft or less. So work on what the odds say you will be doing, folks, extremely rapid draws and shooting, at powder burn distances.