+3 Mag Extension For M3K

[Mumbles Marble Mouth]

Is the +3 mag extension legal for the Stoeger M3K? It's advertised for the M3500 but mentions it fits both the M3000 and M3K. Legal? Illegal? Grey area? Do it but make sure I have the firearms legal defense insurance?

For some clarification, the M3K holds 4rds of 2 3/4" shotsells out of the box. I thought legally you could only extend the maximum capacity of a semi auto shotgun to 5rds of the longest shell the shotgun is chambered for, which is a +2 extension for the 3" chamber of the M3K, but now I have been told it's the maximum capacity of the shell the mag tube was intended for regardless of what your shotgun chamber is marked as. A +3 would allow 5rds of 3.5". Same idea as the pistol mag being used in a rifle. I'm asking because the manufacturer of the +3 ensured me it's legal for the M3K so I ordered it but just getting a feeling of what the general community thinks. I went ahead with the order simply because if I really feel it's too much of a grey area worth taking a risk over that it's pretty easy to make a permanent pin to +2 and the longer tube would look cooler on the M3K.

 

[Leg]

I believe that your original understanding is correct. It’s 5rds for what the shotgun is chambered for, which sounds like it’s 3” in your case. That would likely permit 6 2 3/4” shells if you extended it to 5 3” shells.

 

[Rust]

You can put as long of a magazine tube as you like on there. You just have to block it to legal capacity. Most like to go flush with the end of the barrel. I prefer to have the mag tube stick a little beyond my barrel. That way when I shove the shotgun into the dump boxes for 3Gun, I'm not beating up my chokes.