If you bought it used it probably has 5.45 mags that didn't have the floor plate switched out. A 5.45 mag will accept 223 but it will jam after a few rounds. Most mags for the SAR 3 were re-manufactured East German 5.45.
Yeah i want to be honest about it as i would hope someine would be honeat to me. It shouldnt be about screwing someone over a few hundred dollars. Im better than that sorry. And as far as knowing seelcore yeah i know him. Ive never tried a polymere mag ill buy one this show and see.
Do not get the polymer AK-74 mags. They will not feed reliaby in the SAR-3 without modification to the feed lips and a follower from Robinson Arms.
The SAR-3 was designed to use the mag from the STG-940 system, which is commonly called a "Wieger" mag from the town of WIEsa, GERmany where the STG-940 and mags are made. The SAR-3 was Romania's attempt to enter NATO with an ammo common rifle, and using the already available and approved mag was supposed to help.
Unfortunately when Century imported the rifle, they used the very cheap (at that time) German AK-74 mag and only opened up the feed lips but didn't change the angle of the follower for the different shape and feed angle of the .223/5.56x45 NATO round.
Wieger mags are easy to tell from all others as they are obviously straighter than the standard AK mag, and are the only AK mag to have two round buttons in the floor plate for disassembly.