Yes one of MH's is an ME. But it is "transgender" and began life as an MH.

Another bit of trivia the Greener breech block is longer than the MH family breech blocks also.

The UPS man just delivered a counterfiet Martini that I bought for evaluation for the book I am writing. It's 1.010 wide.

I used a dial caliper for my measurements,

I don't know, did Malcolm cover the difference between Greener and MH in the Handbook.

Actually the hinge pin should recieve no pressure from firing. All the pressure from firing is bore by the breech block knuckle in the knuckle seat. But you are right about the hump back Greener and MK IV MH being not as strong as the slope back MH (ME) Action. Ever wonder why the ME didn't use the MK IV action, this is why.

I'll bet Greener gets excited when he talks about building rifles on shot gun actions. I do know he is rather assertive when discussing using any split receiver or Webley made action using e-clips to building centerfire rifles.