You don't need to look at the primer to see if the firing pin hit!
(BTW - it grains, not grams. 100 grams would equal 1543.24 grains which would be close to1/4 pound!)

The 3 pellet load is usually unnecessary, and is a great way to develop some bad habits like flinching. I seldom shoot over 100 grains on the range, or hunting. Unless shots are expected at extreme ranges, there just isn't a good reason to burn that much powder. Most rifles I have owned maxed out in performance with 80 to 120 grains of powder. Beyond that the gained very little velocity, and usually lost accuracy.