You may be confusing our postal match with our Musters. The Muster is a CAS style combat match.
For Muster shooting, GAF has no set rules for targets. However, we typicaly use CAS style targets at CAS typical ranges. Our ammunition is loaded to CAS spec, so the use of CAS targets and ranges makes the most sense. In addition. most of our competitors are CAS/SASS folks transitioning/trying out our types of weapons. And our combat scenarios best use this type of arrangement.
I shoot with a local SASS club that allows me to use my GAF weapons as a seperate class under GAF rules. I load as per GAF, engaging their targets as they do, reloading as needed, while ignoring the shotgun targets. Great fun, and generates a lot of interest.
If you have not allready, please read "GAF class structure and Battle Rifle Standards".