I don't know for sure that a caplock is less an eye hazard than a flinter. A flinter produces small but very sharp pieces of flint, but the gas jet from the touchhole might tend to vent it outboard. A caplock can produce larger pieces of copper cap fragments, but the nipple angles back toward your eye. Here's a picture of a caplock going off that I caught at just the right millisecond:
![](https://americanlongrifles.org/forum/proxy.php?request=http%3A%2F%2Ffarm9.staticflickr.com%2F8250%2F8541298724_d32660f2ec_m.jpg&hash=de81a7cfa1c3e23449f625750442615d30c90e5e)
And here's another taken a couple of years later, also percussion, but a different gun:
![](https://americanlongrifles.org/forum/proxy.php?request=http%3A%2F%2Ffarm9.staticflickr.com%2F8518%2F8540211577_e0d6dab60a_m.jpg&hash=3a998563ca7ef34699a4c82b45370eb2dd4c7904)
The moral to the story, I guess, is not that one ignition system is riskier than the other, but that you should always wear dependable eye protection.