The Geissele 13.5in MK14 Super Modular Rail will not work with the Aero Precision M4E1 Enhanced upper receivers. You will need to use the Aero Precision Enhanced Handguards with that upper receiver.
Per Geissele, Effective 3/31/20 Geissele will no longer include the gas blocks with the rails. It will include the barrel nut, but they also stopped including the barrel nut wrench. The barrel nut wrench and gas block now need to be purchased separately. Geissele never included the gas tube with their handguards.
Per Geissele, there is no longer a barrel nut wrench included. It can be found here:
https://www.opticsplanet.com/geissele-barrel-nut-wrench-02-243.html
No, the Geissele 13.5in MK14 Super Modular Rail is only compatible with AR15 platform rifles. It does not fit DPMS or Armalite pattern AR10 rifles.
The Geissele 13.5in MK14 Super Modular Rail features (2) QD slots built into the rail that are ready to accept a QD stud out of the box.
The Geissele 13.5in MK14 Super Modular Rail will work with Mil-Spec AR15's. So it will work with a Sig M400 Tread Snakebite.
The Geissele 13.5in MK14 Super Modular Rail will work with a Blackout Defense upper receiver. The Geissele 13.5in MK14 Super Modular Rail should also work with a 13.9" barrel.
Please email us at techsales@opticsplanet.com so we can get some more information from you regarding the problem you are having.
The inner diameter is 1.27" inches
Per Geissele, Effective 3/31/20, Geissele will no longer include the gas blocks with the rails. It will include the barrel nut, but they also stopped including the barrel nut wrench. The barrel nut wrench and gas block now need to be purchased separately.