Not to mention that said mounts do move easily, as when so much weight is put on the carry handles they tend to wiggle loose over extended use. Was one of the big issues the SEALS had with the rifle when they first came out. Needing to resight your gun everytime you come out of the bush from a mission was a major pain. Best to go with a high mount from the gun itself. Gets the lense down a little lower which will help with the check rest issue as well.
"The hydrogen economy car from the people who brought you the 'Hindenburg
'" - Glen Foster
Condoms do not guarantee safe sex any more. A friend of mine wore one and was shot by the woman's husband!