HS-6, and for that matter HS-5 and HS-7, are just as hard to ignite as W296/H110 and are equally deserving of a magnum primer. If you are using a "light load" of HS-6 I would recommend a magnum primer even more than if you were using a load up near the top of the pressure range. HS-6 is erratic when loaded light or anything other than up near the top of the pressure range. A magnum primer aids in a more complete burn when using a light load of HS-6.TonyT said:I have never used anything but standard small pistol primers in 9mm Luger. For that matter with light loads i also use them in 357 magnum cases. If you want to ignite charges of W-296 or IMR-4227 then a magnum primer is a necessity in 357 Magnum.