Got a new Mossberg 930. It's the model 85325 which comes with a 28" barrel and an 18 " barrel. I plan to use it for home defense with the 18" barrel and occasionally shoot some clays with the 28" barrel. I'm happy with the out of the box setup of this gun except for one thing. The shell capacity is 4+1. I see there are some aftermarket magazine extensions available. Has anyone had any experience with adding a magazine extension to a Mossy 930? Are they reliable? Do you need to permanently modify the gun? I appreciate any info.