BudsGunShop.com - Steel shot

Gordon, yes steel shot is ok for use with this gun as long as you are using Improved Cylinder or Cylinder choke tubes. I got this information straight from the owners manual, pg 14, seen here >>>> https://issuu.com/eaacorp/docs/updated_girsan_mc312?e=16930521/66484460 .....Have a great day!

Gordon, yes Sir you can. Just about any modern shotgun can shoot steel shot without issue. The only caveat is to use up to BB through a full choke and larger shot through a modified or Improved choke as steel does not compress like lead shot. Cheers and stay safe!

Was reading the eea manual for this shotgun and it said to choose the correct choke and that the choke meant for steel shot will clearly state it's ok to shoot steel shells on the side of the choke
So yes as long as you use the correct choke that specifically states its safe to use steel shot with. Hope this helps.

Pretty sure that would be fine. But I couldn't find anywhere online that states that its nitro proofed and rated for steel shot.
Id contact EAA for a definitive answer
Email: Customer Support
eaa.support@eaacorp.com