One of the factors to reliable feeding is the angle of the ramp. We all know that the standard .45 frame ramp should be 31½° for optimal feeding. Ramped barrels are a mystery in this regard. A well regarded 1911 'smith and I had a private conversation about this and he said he uses a 20° angle for his ramped barrel 9mm builds. I was skeptical but he insisted it worked as well as the 31½° of a standard frame ramp. I didn't ask if his angle worked with multiple ammo types.