BioShock Infinite: The Complete Edition

This one can be a little tricky. Ironsides is a plasmid that lets you steal bullets from an enemy's gun while they fire and then inserts into your gun. I didn't get it in my first playthrough, so what I did was reload the chapter "Return to Rapture". The best way to get the achievement is to hold LT when enemies fire at you. The single activation doesn't seem to work very well. When you load the chapter you will hear Ryan talk and send a bunch of enemies at you. Use Ironsides on these enemies, then keep reloading the chapter until you have it. It shouldn't be too hard this way.

-This does work in 1998 mode (thanks to Samarin6 for confirming) - "yes it works in 1998 mode, just make sure you aren't full on ammo for your equipped weapon as you can't gain any more"

- You can also do this against a standard turret. You can "summon" a turret by purposely hitting a red node when lockpicking. However, I personally don't suggest doing this because certain people (including myself) had trouble getting it to work on turrets.

Here's a video if you required extra guidance.

Credit for video goes to Reabo. Thanks again

The above guide is great just wanted to let people know an easy way I found to get the achievement pretty much as soon as you get ironsides. Once you get it and go through the vents you have a handful of enemies in the area that you can aggro and drag down to the bottom area where there is a dollar bill machine to just continually refill your salts while you let them use you for target practice.