Montgomery Ward 22 long Model number M852 was made by Mossberg also know as Mossberg Model 341 for magazine I found one at www.havlinsales.com
your western field was made by mossberg.There model number for cross reference would be the mossberg model 341.
The US and other NATO forces use the 9mm NATO cartridge, which uses a 124 grain projectile. It also puts out significantly higher chamber pressure than a regular 9x19 Parabellum cartridge, so I would not recommend using it in a firearm which isn't rated for +P ammo.