I figured the same, less stress on the spring. So my Mossberg 590 is stored minus 3, alternating shot/slugs. Chamber empty, safety on, and due to California law (grandkids in and out of the home) I have a trigger lock but key accessible to me (CA law sucks).
The Mossberg 590A1 passed this requirement of MIL-S-3443G:
ROUGH HANDLING
After completion of the performance test, three weapons shall be chosen and subjected to the rough handling test. Each weapon will have the safety “on”, a primed cartridge case in the chamber, and a fully loaded magazine. One weapon shall be conditioned at -20 degrees F, one at ambient, and one at +120 degrees F for a minimum of four hours prior to the test. The weapons shall be dropped a minimum of four feet (lowest point on the weapon to the drop surface) in each of the following five modes:
Butt end down
right side down
left side down
top side down
45 degree angle with verticle plane- butt end down
The drop surface shall be 85 + 5 Durometer (Shore A) rubber mat, one inch thick, backed by concrete. At the test conclusion the weapon must be safe and serviceable and the primed shell shall not have fired.