What are the OCR grade boundaries in the GCSE courses? Here's the current information given by OCR the awarding body. They will also publish specific grade boundaries and raw scores for the January and June exams with the results.
As a rough guide, the Foundation tier papers are targeted at 70% of the marks at low demand (grades E, F, G, U) and 30% at standard demand (C and D). The Higher papers are targeted at 50% standard demand and 50% high demand (A*, A, B).
Anyone getting 75-80% on a Foundation paper should be on C level. On Higher papers 50% for C, and 75-80% for A is an again rough guide for attainment.
The exact boundaries will vary from paper to paper at awarding. This answer applies to all C21 courses (except Entry level).
