As a general rule of thumb, a Grand Master who shoots in both Open Division and Limited Division will shoot approximately 8% faster with Open gear across the board. That's why the equipment race began in the first place. The advantage in Open is due mostly to the optical sight, and of course the comp. The advantage gained by optics and a comp depends in a large part on the distance to the targets. The closer the targets (all other variables removed) the less the advantage. In some cases, as in hoser targets, the advantage will actually go to irons. In fact, The Burner did very well in the Open Nationals a few years back shooting iron sights against the dot folks.
In the case of the El Presidente (CM99-11) the high hit factor (hhf) for Open is 11% higher than it is for Limited. Of course, the hit factor is determined by both time and accuracy. While I am at it, the high hit factor for Limited 10 is the same as the Limited HHF. In Production Division the HHF is set 5% below the Limited HHF because of the minor scoring.
I have shot CM99-11 in Open division clean, all A zone hits in under 5 seconds. I have also shot the El Presidente (CM99-11) with 6 A zone hits and 6 C hits or better with Limited gear in 5.5 seconds or less more times than I can remember. Two of my best "Limited" runs in a match were done back to back at the High Country Steel Match in Wyoming on steel IPSC targets in front of a sizeable peanut gallery (for little old podunk). My combined times for two runs was 10.84 seconds. We didn't have scoring rings (duh, it's steel), but all hits were COM and you could cover all 24 rounds with a paper plate. Alas, that wasn't good enough. Sam J. and Scott G. (both Limited Masters, edged me out by fractions of a second).
Andy, your memories of the past are nice, but listen dude, either you can shoot or you can't. Which is it? I too have a past but I haven't even bothered to discuss what I was doing in my prime. Are you pissed because I started IPSC at 45 years of age and I have accomplished more in 4 short years with bifocals and arthritic hands than you have accomplished over your entire IPSC career?