HI mate welcome to the forum..
I have a few questions for you, where will you be doing the iron plate competition and what are their rules, how many targets? Under time limit? What's the shooting distance? What guns will they let you use? Pellet? 4.5mm BB, 6mm BB's?
Once I know all those I can help better.....
But just to quickly answer, I have the umarex Beretta 92fs, I think it's a great gun. But I choose true semi auto pistols over it to do IPAS with..
I have the umarex 1911a1 as well and if I'm honest I don't like it for a few reasons. Out of the box the grip safety feels awful in your hand still and crunchy so unless your willing to strip it down and work on it, it's not comfortable to shoot.. Plus the two peice trigger feels and looks rubbish..
The cp88 like the beretta is a good gun, but again I would choose a true semi auto over it,, which these pellet guns with the 8 shot rotary magazines which is turned buy your trigger pull or cooking of the hammer makes the trigger pull long and a bit stiff in double action, if the pellets are seated correctly the feel is made better but it's still longer and heavier then any true semi auto pistol.. If you cock the hammer first and shot the guns in single action the trigger pull is nice enough, but if your IPAS competition is timed, then you don't want to be clicking the hammer each shot and taking up extra time doing so.
Also most if not all of the umarex cp88 1911a1 and beretta 92fs shoot at 1" to 1.5" high of POA at 20-25ft so you have to compensate for that.. Out of those three guns I find the beretta 92fs to shot more accurately and I use it in a few comps myself, but it does depend on the pellet used and the shooter too..
But the cp88 comp version is also more accurate then the 1911 and standard cp88 because of the extended barrel..
The umarex 586 or 686, as Harvey says has a 10 shot mag but there's a good change your only be shooting 3 or 5 shots at a single time anyway?
But the 686 does have a slightly better trigger pull in double action then the 3 above pistols, and is an accurate gin too some say a bit more accurate then the above 3 pistols at a longer range.. And another good thing about this gun is it comes with fully adjustable sights..
Out of those pistols I would choose the 686 for sure..
BUT if you are allowed to use other guns apart from pellet guns I would recommend you different guns still..
Also on umarexboysclub forum, we have our own take on IPAS competition shooting and do a shooting competition called PIPAS you can do this shooting competition at home and it will help you practice so you should come join mate.
ATB Marc
Some of my favourite guns in. You collection, Umarex Beretta 92fs - Colt Custom 1911 - Walther Lever Action - TM Hi-Capa Custom Build Project - Colt SAA .45 & many more..