Can I assume you bought it used without the manual? Although it sounds like you're operating it correctly.[/size]If the 1 3/4 shells are not cycling, My guess (and it is a guess) is that they might not be long enough to reach the load gate activation lever (linked to the small black button you are pushing).If you are only going to use that length shell, you may need to extend that latch.The CZ 712 semi-automatic shotgun must firstly be set to condition when the carrier makes it possible to place shells into themagazine. For this reason pull the operating handle back until the bolt locks in the rearward position. Now grasp the firearm from belowand depress the bolt release button located at the receiver’s side (Fig. 2) so that the bolt snaps closed and is locked at the front. Bear inmind that this operation can be dangerous if done carelessly and therefore be extremely careful! Engage the safety of the firearm byshifting the safety to its "On-Safe" position (see section "The Safety and its Operation"). Put shells one after another into the magazinetube located in the forend by placing them on the carrier and pushing forward in the direction of fire until they are fully inserted. When youhave loaded the desired number of shells push the shells drop lever (Fig. 3), to allow the shell to be released from the magazine. Nowretract the bolt operating handle and then release the bolt to close forcefully. This operation chambers the shell and cocks the firingmechanism. The firearm is now loaded and the safety engaged to prevent any unintended discharge.
During ShootingThe CZ 712 model mechanism automatically ejects the fired shells through the ejection port and afterwards picks up a new shell fromthe magazine and chambers it. When the last cartridge has been fired the bolt will stay to the rear (open), thus signalling that the magazineis empty.