I have to disagree, somewhat. The effectiveness of nipples if often a function of the design of the lock to which it is attached. A drum and nipple arrangement has a built in 90 Degree angle that has to be traveled by the flame. A patent Breech usually does not have that sharp angle. Underhammer guns, and mule ear guns have the nipple screwed into the barrel, on the bottom, or side, respectively. Not only is there no Right angle to surmount, but the flame does not have to travel as far to ignite the powder. Standard primers are all that is needed. On these later two styles of actions, you probably want to use a nipple with a smaller hole, because the nipple is so close to the chamber pressure. However, the Hotshot nipple has an adequate construction, as do most of the other, after market nipples available.
The concern about blowback, where a nipple is so open that gas comes back from the rifle's chambers and blows the primer back against the hammer, making the hammer ' cock ", often far enough for the primer to leave the nipple and go flying off who-knows-where, is a real one. However, it is best dealt with by having a hammer with a proper skirt that directs any broken primer cap particles away from the shooter's face and hand. On Hawkin style guns, the skirt usually has a hairlip cut in the front of the skirt, so that any pieces fly forward, away from the hands, and face of the shooter.
I am using stainless steel nipples on my 12 ga. shotgun, and have no complaints. I have no misfires, because I took the time years ago, when I first got the gun, to grind away the face of the hammer so that it strikes the entire top of the nipple on every hit. With many strikes, the nipples show peening, a buldging of the nipple just below the top edge, which is the result of repeated blows, just as would happen if you hit a rivet with the head of a hammer. Some nipples resist this more than others. I am told the berylium copper nipples are among those, but have no personal experience with them.