Good luck finding an 870 factory choke threaded barrel for $120 or less. The Express barrels are supposed to be made by Mossberg and may or may not use a detent ball or ratchet system for attachment depending on date of manufacture.These will both fit a Wingmaster but may need a little chamber polishing to slick up?Sell your fixed choke barrel then add $100 and buy a threaded choke replacement.Harold