Interesting Thread
While we don't shoot formal 3-gun at our club, we do have Carbine events that go out no further than 100-yds. Most stages are "IDPA" distances. I have both platforms, have shot both at these events where the AR clearly is the platform of choice for most shooters.
I recently took an all day class with 3 of my fellow competitors designed to build up our skills for these events. The more of us who have been taught more "advanced" skills, the more interesting stages can be considered. Additionally, as one of the RO's at these events it's useful to to see how the senior staff manages some exercises. I was the only one shooting a Commie Rifle, the other 3 were shooting AR's.
At "IDPA" distances, I'd have to agree with Correia's comments. It's less the platform and more about the skill and dedication to practice of the shooter. My hits compared favorably to my classmates, although they at times had slightly tighter groups. During rapid mounting drills, most often I would do as well or better (legs have slowed down, but stationary reflexes still aren't too bad
). During reload drills, most often I surpassed their speed (because of intensive dry-fire practice). At the end of the day, young legs prevailed and in some House runs I simply couldn't keep up with one of the younger/fitter participants.
As to platform specifics, I've "customized" the iron sights by filing a V in the rear to more easily pick up the front sight, and I filed a notch in the safety lever so I can keep the bolt back for chamber inspections and stay open for chamber flag insertion between runs. My short fingers don't really allow for indexing the safety off at the buzzer, but my reaction time is still pretty good so I end up doing alright. My out of the box trigger (Global Trades/Arsenal Inc. SSR-56) tips the Lyman scale at about 3.5#. My 20" Bushmaster in contrast is closer to 7.5# (but it doesn't feel that heavy during firing). As much practicing as I've done with "rock & lock", a pair of cinched AR mag's switch much more easily than cinched AK mag's (lighter too).
For formal 3-gun, if you want to win...clearly the AK provides some significant challenges to be overcome. However, if you simply desire the opportunity to get in some practice with your Commie Rifle...as long as you are safe, go for it. These types of events are useful to see how you and your equipment perform under some stress. I found that while on most occasions I can rock & lock cinched AK mag's just fine, too often with my 20-rd Tankers I had issues (if I wasn't perfect, the rounds might slip a hair and cause some malf's). I switched to 30-rd Polymer mag's and did much better.
In any Defensive Shooting event, there are those that will concentrate on the trophies (and there is nothing wrong with that) as well as those that concentrate on the "defensive practice" (and there is nothing wrong with that either).
We have a Carbine Practice we are trying to organize this weekend. That "young whippersnapper" will likely be there with his AR...and I'll be there with mine
. I want every advantage I can get!!
Safe shooting,
CZ52'
I had two PMI 30 rounders for the mini. Ran good. 
