50,000 (now 88K) rounds and counting: Springfield Operator

[Heavy Metal]

Yeah, that middle section is pretty much not participating in guiding the slide, but you could say that it helps keep crud out. Indeed Colt has been doing that for years, removing the bridge just over the slide stop window, starting on the 10mm's. The Guncrafter .50GI has them removed completely from the front to the back of the mag well.... no problem.

I suspect to stop people from calling and complaining the frame rail cracked.

What causes this crack? Frame Flex under recoil?