The SLR ION Hybrid M-LOK 5.56 Handguard will fit and function as intended on an Aero Precision M4E1.
The manufacturer doesn't state if the SLR ION Hybrid M-LOK 5.56 Handguard will work with Piston Driven AR's. I recommend contacting the manufacturer to confirm compatibility.
MPN: ION9.7ML-HYB is the same Gen 5 ION Hybrid MLOK available from SLR. We're always carrying the most up-to-date products from our suppliers.
The internal dimensions are 1.35", but SLR does not list the external dimensions of the ION Hybrid.
Yes, it will.
It does have a break in the top rail as pictured.
It depends on which length you are interested in. Please contact us at techsales@opticsplanet.com with an identifying number for the specific hanfguard you are looking for, so we can confirm the weight.