The breechface cut is a significant improvement for consistency and robustness of both extraction and ejection in Glocks. The thing I think many people don't realize is that Glocks without it (gen 1-4 and early gen 5, for the most part) are always on the ragged edge of barely extracting or ejecting. That's just my opinion. They work and are generally reliable a majority of the time, but that doesn't necessarily mean they are
great at performing those two functions of cycle. They can be better. Here's some vids to demonstrate the point:
G19.3:
https://www.youtube.com/watch?v=tBHkGaWU1Lg
G34.3:
https://www.youtube.com/watch?v=4uotsMABUb4
G17.4:
https://www.youtube.com/watch?v=CbgrioNpJSA
G17.4 and G23:
https://www.youtube.com/watch?v=IOAtSPHmgwU
G23:
https://www.youtube.com/watch?v=QM_30OHgfNA
G19X:
https://youtu.be/Alr6mjmzKGs?t=132
G20:
https://www.youtube.com/watch?v=ABBfc_uq_Is
Custom G19 (appears to be a gen 4):
https://www.youtube.com/watch?v=hkrX6BVO8xc
Suppressed G19.3:
https://www.youtube.com/watch?v=klnKLqlq2e8
P80 + RMR + Comp:
https://www.youtube.com/watch?v=sWWtQdU1c8Y (I know, far from OEM or stock, but interesting nonetheless)
Some of those may seem irrelevant, but the interesting thing to note is some of the common characteristics across models, calibers, and configurations. For one, the brass appearing to often slam into either the breech face or front of the extractor sideways as it's ejecting. Another variant of that is the brass contacting the right side of the lowered ejection port wall, causing the brass to achieve a significantly vertical arc. Also, pretty frequently you'll see brass just dribbling out of the ejection port as opposed to being flung a fair distance of several feet or more. Generally all things that aren't confidence inspiring.
Contrast that with a well-tuned 1911 extractor and ejector. Here's Hilton Yam with several Staccato 2011's and a G19.5. Notice across all of these, including the G19, the consistency of the pattern or arc of ejection. Personally, THAT is what I want to see from a gun, but I am weird.
https://youtu.be/Rf12GnB27tI?t=422
For improving extraction or ejection on older Glocks a few common options are:
- Apex Tactical extractor
- Glock 30274 ejector (for 9mm only) (Sometimes you can find the ejector-only on eBay, but generally have to buy a gen 4 trigger housing from most places.)
- White Sound Defense H.R.E.D. extractor plunger: 9mm, .357sig/40sw
- Test with hotter/better quality ammo like: Speer Lawman, Winchester NATO (Q4318 or other brand at proper NATO spec), Federal HST, Speer Gold Dot, anything from Black Hills, etc.