From what I read...And take that for what it's worth...It affects range but not accuracy.  The reason is that bullet drop, in and of itself, is predictable.  Hence holdovers and bullet drop indicators on scopes.  What has to be accounted for is variance (what the shooting world calls "flyers").  So dropping bullets can still be accurate, you compensate for them with holdover. 

The longer barrel will mean less holdover but the bullet path will still be predictable and thus accurate.

You can see it in youtube videos when a trace the bullet path of a long-range rifle shot.  You can see the drop in the bullet over distance but the impact point is spot on. 

So what I take away from that is that any barrel that preserves the stability of the bullet is a good thing.  But that's only half the equation.  The other half is the ammo.  If flight characteristics of the bullet are unpredictable then more flyers. 

Gee, I guess we'll have to test this extensively uh?

Got an answer to my own question via several articles on the interweb.  It appears that there is no appreciable improvement in accuracy based on barrel length.  Velocity seems to be the only function affected. 

Greeting all.  First post.  Thanks in advance for your help.

I have a gen 3 Glock 20.  It has an apex trigger and a KKM 4.5in a barrel which seems to be accurate to 15 yards.  I'm wanting to configure it for hunting hogs and deer.  I have a vortex venom to put on board and I'm wondering about the barrel.

My question is will a 6in kkm barrel provide more accuracy than the 4.5in barrel out to 50 yards?  I understand the velocity will pick up but I'm more concerned about putting the shot on spot.

Thanks