Midwest Industries has their suppressor handguards that are 1.670 but the lengths aren't quite what you're looking for. However, with some modification if you cut the first two mlok slots off the OAL will be about 11.87" with a diameter that works.
AR-15 suppressor compatible handguards from Midwest Industries, a U.S. manufacturer of quality tactical rifle accessories. Quality components, competitive pricing, and top notch customer service.
I ordered Griffin 11.5” with 1.54”ID.
Video shows how extra special and all. I will post initial impressions when it arrives and mounts square, I hope.
This is a less than ideal mounting solution with difficulty indexing properly and needing material removed for forward take down pivot area. Returning it.
ETA: I think it’s being discontinued anyway with respect to relevance.
This is a less than ideal mounting solution with difficulty indexing properly and needing material removed for forward take down pivot area. Returning it.
ETA: I think it’s being discontinued anyway with respect to relevance.
I have a Griffin SR handguard: if you slide it back tight on the nut, yes, it will contact the pivot pin area. However, I believe there is supposed to be a slight gap there with any handguard. How else would it pivot?
Another option would be the Aero Precision Enhanced line. Use their nut. Handguard has a 1.72 ID.