Weight Training for beginners Curling problem?????

I'm just a beginner at weight training. I curl 30 lbs on each arm and I do about 8-16 reps with 2-3 sets it's just that i feel that my form is fine and that I can only curl the weights 8-16 each set but when I curl them I don't feel any stretch in my muscles but I feel like my form is fine weird??????