The mentioned website is definitely legit. I've purchased both ammo and the mentioned primers through it several times, with no issues. Be aware the listed Argentine made primers WILL require firm seating to function. On my Dillon 550, I first seat as normal with firm handle pressure, then while still at the priming station, I apply a 2nd very firm push on the handle. When this method, is applied they shoot 100% in both semi-auto's and revolvers that have full factory spec springs and firing pins. Reliability is considerably less with "match tuned" pistols.