I just installed the new compression parts (101% seal now), assembled the gun with the silicone MR and the chrono readings were the following (hop all the way off):
325, 300, 240, 170, 90, jam. Didn't test full auto for obvious reasons.
Good ol' rubber 50° MR in, constant 315 without hop, constant 325 with hop applied.
depending on the setup having it all the way off can be bad as the bb can pretty much just roll down the barrel giving really wacky chrono readings, it's one of the reasons i hate sites that think it's a sensible thing to do as part of chrono policy.
generally i'll set them kind of by eye or halfway on just to eliminate that issue (gun dependant ofc)