It is a Mossberg 590 with a 20" barrel and can hold 8 rounds in the magazine tube. And yes, I have a safe as I don't leave unattended guns loaded in the home. Ammo listed below is 2.75" 00 buck shells Spring 1 - original one it came with from the factory. After test firing the new weapon with a few boxes of ammo I loaded 8 rounds in the magazine and left it in the safe for one or two years. At that point I took a Loui Awerbuck class. The shotgun was working fine (never failed to deposit a shell onto the shell lifter) but the magazine tube felt week so we swaped it out. The spring was very short and the conclusion was that it must have been an incorrect short spring from the factory. Several springs later determined that wasn't likely the case. Spring 2 - was whatever the local range had. The spring was about 9 to 12" longer than the magazine tube (what I've been told is what you want). It worked well for the class. I went home and loaded 8 shells into the magazine tube and ordered factory Mossberg magazine spring so I would have them ready in the future if I needed them. About a year later I was going to take another shotgun class. Prior to the class I checked the magazine tube spring. It was as weak and the same length as spring 1. No biggie, I just put in the new Mossberg factory spring for the class. Spring 3 - the new Mossberg factory spring worked fine and provided flawless performane of the Mossberg 590. I had mentioned to the instructor what I had observed. He suggested that I store the shotgun with only 5 shells in it so the spring would be less compressed. After the class, I stored the shotgun with 5 (out of a possible 8 max capacity) in the magazine tube. About a year later, I checked the spring tension. The magazine tube spring felt weaker but maybe not quite as bad as before. Spring 4 - this time, I used a Wolf spring as I had heard good things about these springs. I loaded the magazine tube with 5 rounds. After 6 months or a year (my memory is foggy on when I did the install), I checked the magazine tube spring and it feels nice and strong. I plan to stick with Wolf springs for the magazine tube. Though some of the tubes weakened over time, they never failed on me to work. So far I'm happy with the Wolf spring (and I have another two new ones at home). I thought you might all find this interesting even though it isn't scientific. It's taken a while for me to "collect" this data.