There are two types available from Numrich gun parts for $24-$27. Type depends on how it locks up in your Shotgun.
Try Numrich Gun Parts Corp.
model 55 the original marlin goose gun
$80- $150, if it has the magazine, and if it's in decent shape.
Gun shops, e-gunparts.com, gun shows, want ads, etc..
www.gunsamerica should be able to help
You have a problem that needs the attention of a gunsmith.
Try contacting Marlin parts. Consumer Parts Orders: Consumer Service Dept: (800)544-8892
Depending on overall condition.Your Marlin goose gun will range in price from 55-200 dollars.
Did marlin make a goose gun with a thirty nine inch barrel
Try e-gunparts.com, gun shops, gun shows, want ads.
Try e-gunparts.com, gun shops, gun shows, internet
Marlin Fireamrs by Brophy.I can say that the Marlin model 55 shotgun was made from 1950-1965.The marlin model 55 goose gun which had a 36in barrel was made from 1962-1996.