Practical Accuracy

25 yards...for what? Defense. At 25 yards, it's not defense, it's OFFENSE. At least, that's probably how a court would see it in most circumstances. But throwing that all out for a minute... when you go up to the target during the ceasefire, take it off the A-Frame or overhead clips, hold it up to your chest. Are most of the bullets in your chest? Then they'd be in the badguy's chest.

10 inches may seem big, but if you're doing it quickly, it's certainly satisfactory in my book. If thats your best though I would recommend some trigger control practice. (Dry fire!)

With a combat type handgun, keeping all my shots in the A-zone of either the IDPA or IPSC target at 25 yards at a respectable pace is good enough for me. (approx 1 shot/1 second)

On the other hand with my 'hunting revolver' (4" bbl, iron sights) I keep all shots within a 2" group, (approx 1 shot/5 seconds) and I think that is good enough also.

ETA: Metapotent asked another good question, I was approaching the situation as standing/off hand.

10 inches at 25yds isn't that bad. I wouldn't call it 'proficient' though. I can usually put 8 rounds in 5-8 inches from 1911 .45 at that range and I only shoot handguns once ever couple months.

Now, you are talking about while standing right? You're not discussing bench pistol shooting are you?

I shoot my G19 a fair amount, and have found I like the 3.5 lb connector with the NY-1 spring. It gives the trigger a very different feel, smooth and steady, but still 5-6lbs. For the cost of the parts I would recommend trying them and seeing if you like them. It is actually a more durable/reliable setup than the stock trigger return spring, so that's and added bonus. All 3 Glock shooters (besides me) who I personally know use it.

My best advice is dry fire, and lots of it, until that front sight doesnt move a micron when you pull the trigger. Concentrate on the front sight and press the trigger straight back. I sometimes lay a penny or dime on my front sight to make sure its not moving.

Practical Accuracy for what?

Defense shooting?
Keeping it COM at 25 yards, and it sounds like that's what you are doing, is OK. But you don't want to settle for that. Keep practicing.

Informal target shooting?
I'd say 3-4 inches at 25 yards isn't bad or all shots (offhand) in a silhouette target at 100 yards isn't bad.

The way to discover what's good enough for you is to engage in some regulated competition.

Since you're asking about practical accuracy and using defensive-type handguns, the best competition to find this out would be IDPA or USPSA/IPSC.

Don't think you have to be a better shot to try them out (the accuracy you describe is better than good enough to get started), and don't think you'll need some elaborate setup; you won't. Just find a local range where it's done (available on-line), and read the rulebook for the type of competition they're doing (available on-line), and then go and watch a match. See how folks shoot when they're moving, and using cover, and engaging multiple targets with obstacles, and shooting moving targets, and so on. Then, next time, bring your gun and shoot--as the folks at the match you watch will DOUBTLESS encourage you to. THAT is how you determine practical accuracy; and it's a LOT more fun than just standing there making ever smaller groups (though that has its charm as well ).

With the best-shooting handgun I own, the Holy Grail (a 1938 Colt Woodsman) I can put ten shots into 1 3/4 inches at 25 yards from a modified weaver position. With my Colt Model .357 I can do nearly as well. With my Kimber Classic, it's more like three inches.

I practice with my BHP with Crimson Trace lasergrips for Home-Defense. I practice at 15 yards because I expect to shoot for real at about "across-the-room" distance of 4 to 7 yards. My eyes are old; that's why I use laser for help. I can put 18 relatively quick shots in 5 inch grouping at 15 yards... shooting from my hip... at multiple targets. I can't make 1 inch groupings on a target sheet, even slow-fire at 3 yards - but I feel quite confident of defending myself in real life.

My carry-gun is a S&W-442 with Crimson Trace lasergrips. I'm not as "accurate" with it as with my BHP, but I expect that any real-life use will be at closer range.

"Practical" being defined as good or better than adequate for defense situations it sounds as if you're GTG, since most shootouts with handguns take place at ranges much closer than the distance you're shooting at.

If you can do 10" @ 25 yards, it doesn't sound as if it should be a stretch for you to be able to do 2" +~ at 5 yds, if not better than that. Try setting the same size target at 5-7 yards, and see how well you can do then. Once you're sure you've got the 'practical' 2" or less @ close range, then keep advancing the range. Eventually that 25 yd. group will tighten up a good bit.

Poor college student? New shooter? Please, please get a .22 handgun, or even an advantage arms conversion for your G19. Shoot it often for cheap. Cheap like $90 for 5000 rounds.

Think of it this way.

Stand in your kitchen. If you can hit your Fridge from the Sink dead center, you'll probably be alright in any scenario where you'd want to pop someone.

Unless your planning on crazy viligateism. Then you might want to keep practising.