HOW DO I GET THESE APART?
The 18588 Six Barrel Shooter and the 18587 Trigger are two pieces that once together aren’t meant to come apart.
I don’t know if there is a really good reason to try to separate these pieces. If you need one and not the other just don’t assemble a new one or you can easily buy them separately on Bricklink.
You got to flip it over and just a butter knife. Same warnings apply to this as with the Bionicle heads. You can wedge one knife behind the trigger piece and with another knife on the other side. If you tilt the knives in, it will contract. Another person will have to use something to push it through.
I didn’t have any helpers today but you can see the damage I caused to the pieces trying to get it apart. I have actually succeeded before but it isn’t worth it. Both pieces are fairly cheap on Bricklink. If I have any available in my store they will be available here: 18588 and 18587. Otherwise I don’t recommend trying to separate these.