And this is where I have a slightly different opinion on front sight hoods.
I believe, and I'm frequently wrong, that with a rifle you're not focusing on the front sight the same way you would a pistol. It's way-y-y-y out there. It's closer to the same focal plane as a target. What I want is a well defined, black sight that gives me a sharp sight picture. I want more direct sunlight on the target than on the front sight. Light on the front sight would is not desirable, but would cause the front sight to appear hazy or blurry or less defined. Less contrast to the target.
I also believe that a hood, in the field, is a detriment. Rather than protecting the front sight, they provide a place that can get clogged with dirt, snow and other debris making the sight unusable. And a clogged hood is not easy to clean out quickly
SO, where can I find support for my theory. What do the big boys, use?
If you accept Camp Perry as the definitive example of iron-sighted rifle shooting, then you'll notice many, if not most, use hooded front sights. I don't think that with the precision involved they would leave those hoods in place unless there was an sight picture advantage to using them. Protecting their front sights, at least while on the firing line, isn't a problem for them.
Then if you look at military arms, where front sight protection might be at a premium, none that I have found came with a complete hood. (There could be some, I'm not the definitive expert) Many have "wings" on either side. Wings would provide some protection but allow for quick removal of debris.
That's my belief. Fire away.