Here’s story from a very talented person, 737mechanic has made his own Mossberg 590A1 Mag Extension for 18.5 Barrel. The final result is really impressive.
Homemade Mossberg 590A1 Mag Extension for 18.5 Barrel
homemade
Remington 870, Accessories, Upgrades, Tactical, Reviews, Forum
Remington 870 Shotgun Accessories, Upgrades, Reviews, Gunsmithing