RE: anyone grouse hunt with muzz?
 

The only smoothbore that will fit that is the .56 caliber smoothbore Thompson Center sells. You might find that minimal at best. If the rifle was a .54 it would be 1 inch on the flats and you could have used a .62 caliber smoothbore from Green Mountain Barrel.

RE: anyone grouse hunt with muzz?
 

what is .56 cal equal too vrs regular shotgun size

RE: anyone grouse hunt with muzz?
 

I am not sure... a .62 is a 20 gauge.

RE: anyone grouse hunt with muzz?
 

Gauge/ Caliber Weight/gr.
Balls/lb.
8 .835 875
10 .776 700
12 .730 583
13 .710 538
14 .693 500
16 .663 438
20 .615 350
24 .579 292
28 .550 250