Don't worry too much about magazine spring compression / set. Think through the accessability of your shotgun and it's load configuration. By load configuration, I mean load status (magazine, chamber), safety status, hammer cocked or down, etc. There are many configurations but you must set yours up the same way everytime. You have to know what to do when you pick it up. You have to know even when
you are sleepy.
Here's mine: safety on fire, chamber empty, hammer down.
I don't have to fumble for the saftey, it's always on fire. With the hammer down, I can instantly view the load status by gently pulling back the forend before it cocks the hammer and check for an empty chamber. To fire: rack, aim, access.
To set this up, I do have to pull the trigger with the magazine loaded. You do need to hit the action bar lock to check for an empty chamber before you release the hammer / pull the trigger.
The four rules always apply.
1. Handle all firearms as if they were loaded.
2. Never point the gun at anything you're not willing to destroy.
3. Keep your finger off the trigger until sights are on target.
4. Know your target, what is around it and behind it.