Briley makes choke tubes for Yildiz guns but only in 12 gauge Trulock is making them now in standard and extended versions. http://www.trulockchokes.com
Only with cylinder and improved cylinder choke tubes.
Extended - extends beyond the barrel Flush - does not extend beyond the barrel
What gauge and grade is it?
Browning Invector.
A 12 gauge shotgun with changeable choke tubes that fires 3.5" shells.
Browning made choke tubes.
Try gun shops, gun shows, want ads, e-gunparts.com
mossburge chokes r the same as stoegers
Modified describes a choke. Invector is a system of choke tubes.
You don't give us the model, so it is hard to answer the question. Assuming the gun does not have an obvious adjustable choke, the choke is probably not easily adjustable. A gunsmith can open the choke (from Full to Modified for example) or can install internal interchangeable choke tubes (costs around $125).
I am a gun dealer in Asheboro, NC (Franks gun and pawn). Yes, the Baikal choke tubes will fit. This gun is made by Baikal for Remington. It used to be imported under the EAA name. You can also get tubes at Colonial choke tubes.