Hi Aaron and welcome. They will likely work at 1200 fps but a 50 to 100rd full power break in is recommended. Details from an actual owner/shooter here: youtube.com/watch?v=t25VJEpl6jg

it should work just fine as long as the winchesters are 1 1/8 oz at 1200 fps. If they are 11oz at 1200fps you will likely need to use heavier shells before they will reliably function I would try them before going out to buy heavy loads

Hi Aaron, some of these Turkish shotguns need high velocity shells (at least 1300 fps) to cycle properly.
Not saying this one does, you will need to check your owners manual.
You may need to break it in with high velocity shells before these will reliably cycle, or they may work out of the box.
If you're asking if this gun accepts 2 3/4" shells, yes it does.
From Tokarev FAQ page - "1. Does my shotgun require a break in? Shotguns typically will require 50-100rds of ammunition, we recommend a heavy load of 1oz or heavier for break in."
Stay safe & have a great day!