Factory blanks are sometimes offered but difficult to find. I don’t see blank ammo detailed in any of the national catalogs that listing Stay ammo. Now then Aged Western Scrounger has a few but not in each individual caliber. Navy Arms sells five in one blanks but These are plastic https://strapweaponshop.com/product/triple-r-munitions-223-5-56-nato-blanks-100-rounds/