Best the K1127 can do is about M2.5, based on my sims with a truly minimal rocket. I have a good bit of experience with this type of rocket, and have relatively high confidence in my sims.
Now, that's M2.5 with .05" 2024 fins glued to the case, a 10 x.032" payload section using a custom motor case as a coupler, and a partially hollow birch nose cone. This includes a 12" parachute, Merlin Tracker, 2 very small lipos, a RRC2+, and a Pico AA1.
Peak accel of 100G's and altitude of 15Kft.
All that adds a tiny 7.5oz to the weight of the motor.
https://www.mdra-archive.org/photos/redglare3/chuckrudy/Full/RG3BrianMach.wmv (similar rocket from a few years ago)
A "normal" minimum diameter rocket with an airframe I've simmed around M2.