I advise you use three STONE gateways in front of each other with small gaps in between then put a gate in the first and third one. Then shoot it with a tranq to get it to follow you into the trap(preferably when it lands, but if you have good aim go for it I guess) once it's in, close the gates then it'll be stuck so you can tranq it! Also if your settings are standard/mostly standard, and the argy is a high level (like 80-150), use kibble or mutton and/or prime meat. On standard settings, it'll still take a while to tame even with good taking food.