Shotgun storage for extended period

Ghost Recon

I have a semi-auto shotgun that won’t be used for a number of months.
Having read through the user manual, there is no reference to long-term storage.
So, how do I remove tension on the firing spring (or any other tensioned spring for that matter), if I am storing the firearm for an extended period of time (i.e. 6-24 months)?
I’m thinking of using a snap cap in the chamber, then firing the trigger and locking away.
Thoughts please?

JP22

Thats exactly what I did when serving overseas.

Thouroughly clean and oil all metal parts, use snap caps to release cocked springs, some people store muzzle down to avoid oil seepage into the stock, be sure to have some Gel Desiccant Bags in your safe. Store ammo seperately and use a trigger lock if you have one.

Grizzly 45

And if you want to go belt&braces...These are a good investment for our dampish climate when storing firearms.

https://byallen.com/gun-storage/socks-sleeves