I've used apertures on .223 AR-15's, M1 .30-06 Garands, .30 Cal. M1 Carbines, M14 .308's, a couple of Ruger Mini 14's, a Ruger 10/22, a Remington 7600 .30-06, Winchester .30-30 M94's, Marlin lever .44 Magnum 94's, .30-30 336's, M39 .22LR, and 1895 .45-70. Almost forgot the Ghost Ring sighted Benelli semi-auto and Remington M870 .12 gauges. I like them very much. They are extremely lightweight and rugged. Rain, snow, and internal or external fogging doesn't affect them much at all. The aperture sight doesn't affect the natural balance point of the firearm. When one is accustomed to them they are very, very, quick to use. Much arguement over which is faster, the aperture or a wide angle low power scope. Very good shooting can be done with a proper aperture sight and under certain conditions or on certain firearms I absloutely prefer the "peep" sight. The XS Sight System is all steel, rugged, and a very good sight. Lyman and Williams market decent aperture sights and front blade/bead combo's. The older ones made of steel are superior sights, however, as you might guess they are scarce and raise a premium in price. Long distance and small targets would have me choosing a scope. Not that an aperture sight can't be accurate enough for such a chore. Just that I may not be accurate enough with an aperture sight, for the chore. Timber and brush hunting is a natural for this sight and I often choose one of my peep sighted rifles for whitetail hunting, and occasionally, predator calling.