Quadrant target question

If you send me a PM to remind me tomorrow, I will go out and measure exactly. From memory though each quadrant is about 2in by 2in, and the center is about 7/8 of an inch. Please pardon me if that is incorrect, as I'm going off memory. I am quite certain though that the center disk is less than an inch in diameter. 



Honestly though I'm not sure why it really matters, if you're going to make one yourself you can make it to whatever Dimensions you want to shoot at. I personally would be inclined to do 1 MOA diameter minus my pellet diameter for whatever range I would be shooting at. I should also add quickly that my quadrant Target is not as stable as I would like it to be, so if you are going to build one for yourself I would recommend welding a more stable base. 
 
Good on you, Mate, for figuring out the sizes of commercially available targets! I plan to make my own and am considering the following two options: one is to match the size of the center(s) to the accuracy I reasonably expect from my air gun at the distance(s) I plan to shoot. There is no point in making centers smaller than your air gun is capable of grouping or so large that you are able to hit them with sloppy shooting. The other option is to follow the guidelines in Sections 2.3 and 2.5 of the World Field Target Federation rules (www.world-field-target-federation.com/Rules) which stipulate that targets have kill zones of 15, 25 and 40 millimeters and are placed a maximum distance of 20, 35 and 50 meters, respectively. If you have 50 meters available to shoot and make at least 1 target of each size, you could effectively practice under real life field target conditions. Hope these ideas are helpful.

Good luck.

ChrisK