Magnum Research BAR506 Desert Eagle 50 AE 6" Matte Black Steel Fits Desert Eagle Mark XIX
https://www.tandktactical.com/shop/761226022855-magnum-research-bar506-desert-eagle-50-ae-6-matte-black-steel-fits-desert-eagle-mark-xix-7544
https://www.tandktactical.com/web/image/product.template/7544/image_1920?unique=ba43e4f
Once you've purchased a Mark XIX Desert Eagle you can change the barrel length in seconds, if you have the appropriate components in hand.