I had a N. Guyot SXS that had a light primer strike on the right side. (I had just purchased the gun from a dealer.) I tried about 7 different factory and a hand load With a couple different primers. The only ones that performed well were STS and AA factory loads with my handloads firing as well. Herters loads were horrible with the firing pin catching on the primer. Obviously a huge difference in the performance of ammo.

Start with STS factory and experiment from there...