Does anyone have an updated list of compatible hand guards for the system.  Thanks

Oh, are you going to have fun. You'll need to dig up what the clearance measurement is from Osprey, I can't find it at the moment. This was the list I worked from a few months back. Info gleaned from the archives and net searches. Accuracy is questionable, but should give you a starting point. Indications of standard or non standard operating rod I couldn't confirm except for the Seekins rails:

Compatible Osprey OPS-416 Guard List:

Seekins Precision, check measurements but most appear to work. MCSR V2 Free Float Quad Rail fits for sure (this is what I ended up buying). Non standard oprod fits.

Black Dawn Industries - appears they don't want to do business (personal experience, yours may vary).

ALL Midwest P Series Rail work with the standard operating rod.

Midwest Industries 17P Rail System - standard oprod fits

Midwest Industries 20P Rail System - standard oprod fits

Otis Technology’s TRS rail W/ Otis Rail Riser accessory - Standard oprod fits?

Spikes Tactical B.A.R. & Seekins defense B.A.R. (same rail, different branding)  - Non standard oprod fits

American Built Arms MOD1 - Standard oprod fits

Surefire 500 series integrated hand guard with light - Standard oprod fits

Magpul MOE Hand guards - Standard oprod fits  (must modify handguard to fit)

Gen2 Magpul MOE Hand guard - Standard oprod fits

JP LE-M handguard - Non standard oprod fits

Vltor CASV Rails - Standard oprod  fits

Thanks!  Looks like the MCTAR-17P is the winner!