The internal is from the original design and John Moses Browning seldom got things wrong. Most 1911 enthusiasts prefer the original internal extractor. Other semi auto designs usually have an external extractor. And those work fine on the Sig, Glock, Beretta, S&W and the like. Some modern 1911 manufacturers depart from the original Browning 1911 internal design and have incorporated an external extractor on their 1911's. While that makes a purist cringe a properly designed external extractor might have certain advantages and they do work well. The problem is the Kimber external extractor was a complete failure. Kimber used a series of small springs and small over lapping plastic levers to pressure the extractor hook. In the process of trying to make this mess work Kimber had three different size hooks. Essentially it was all trial and error until you found a combination that worked... kinda worked. It was so bad Kimber eventually offered to retro fit those pistols cursed with their external extractor with a completely new slide and internal extractor. While a Sig 1911 with external extractor wouldn't bother me, I wouldn't have a Kimber like that.