When debating internal vs. external extractors, many proponents of the internal extractor point to the fact that the first production 1911s were equipped with internal extractors. This, however, seems to be by request from the U.S. Military during the 1906-1911 Army Pistol Trials, which called for -among other things- ease of disassembly to facilitate servicing the pistol in the field.
It’s worth noting that early prototypes of the 1911 featured an external extractor and many of John Moses Browning’s pistol designs before the 1911 featured external extractors, including the FN M1900, FN Model 1903, Colt Model 1903 Pocket Hammerless, FN M1905, Colt Model 1908 Vest Pocket, Colt Model 1903 Pocket Hammerless and the FN Model 1910. The Colt M1900, Colt M1902 and Colt Model 1903 Pocket Hammer featured internal extractors. I believe that this is evidence that JMB wasn’t religious on the subject.
So which is better?
Internal extractors are simpler. An internal extractor is a single piece of tensile steel with a good degree of “springiness” that must be properly tuned and shaped when installed. By contrast, an external extractor is made up of multiple parts but doesn’t need to be as highly tuned or specialized. An external extractor doesn’t require as much tuning as an internal extractor when first installed.
Internal extractors are more or less interchangeable. That is, an internal extractor from one Series 70 1911 may be dropped into another Series 70 without fuss and a Series 80 internal extractor may be used in another Series 80 1911 or in a Series 70 (note: a Series 70 internal extractor will not fit a Series 80 as the internal extractor in a Series 80 has a cut out to make room for the firing pin block).
External extractors, however, are not standardized across manufacturers. Therefore an external extractor from one manufacturer will very likely not fit another manufacturer’s 1911. External extractors are simpler and cheaper to manufacture.
If you believe that you might find yourself doing a detail strip in the great outdoors or extractor maintenance in a fox hole, having the simpler internal extractor would likely be to your advantage. If you can see yourself in a situation where you may need to replace your extractor from a limited selection of random 1911 parts, an internal extractor will be to your advantage. Internal extractors are more common.
Functionally they behave the same and though early external extractors in 1911s earned a bad reputation, by most accounts external extractors of recent manufacture can be just as reliable as those with internal extractors. There are exceptions to every rule of course, and there are no doubt countless tales of issues with both.