BudsGunShop.com - true 28?

Its a 20 ga action according to the IFG site they use on 2 action sizes 12 ga and everything else is on the 20 ga frame the 20 and the 28 weigh the same "see ****** Advanced production technologies and skilled personnel assure a wide versatility and interchangeability for all parts and components of SLX 600 Series. These models are available in four classic gauges: 12, 20, 28 and 410, on *****different scaled actions 12 and 20. for weight look on chart under SLX600 DELUXE BLK italianfirearmsgroup.com/fair/firearms/shotguns-hunting-600-series

Dean, we are customers like yourself. That is something you would need to take up with the manufacturer.
Italian Firearms Group Customer Service 800-485-1852 or email info@ifg-usa.com
Stay safe & have a great day!

Hi Dean and welcome. My guess would be this is a true 28 gauge action due to the weight compared to the 20 gauge but I would confirm directly with Italian Firearms Group Customer Service at 800-485-1852 or email info@ifg-usa.com --- Cheers and stay safe!