User blog comment:B214/Light Novel Volume 16 spoilers/@comment-202.160.35.23-20131025154940/@comment-10974991-20131029190524

It's better if he dosn't use the infinite snake power because there are two reason. 1. It can bring out the full potential of a sacred gear or it could break the sacred gear, killing the host. So it's better if Issei dosn't use, it's a big risk.