22.10.2008, 04:36
As for rate of fire...
The gun used on the B-25's was a variation of the 75mm L/40 used on the earlier Sherman tanks. I found some references giving a "Shell weight" of about 15lbs for AP rounds. I don't know if that includes the case and powder or not, and I'm not really sure how much an HE warhead would weigh. So lets just say that the loader on the B-25's is dealing with a 20lbs complete round.
For comparison: The loader in an the Abrams or Leopard tanks has a 120mm round to load. AP rounds weigh in at about 40lbs for a 1980's vintage round and about 55lbs for a current AP round. HEAT, MPAT, and Cannister rounds all weigh in at about 50lbs.
A loader in an Abrams tank is expected to be able to pull a round from the ready rack, turn it through 180 degrees so it faces the proper way, shove it in the breech, get himself clear of the recoil path, and arm the weapon, in under 10 seconds. Most loaders do so faster.
I would say that your B-25 loader could probably have his gun reloaded in under 10 seconds rather easily. Maybe even half that time. He has a lighter round to work with, and as his shells would be brass cased rather than combustible, he might be able to skip the steps of having to pull one from a rack for the first reload and instead simply have it sitting on his lap or held in his hands. ('Lap-loading')
The gun used on the B-25's was a variation of the 75mm L/40 used on the earlier Sherman tanks. I found some references giving a "Shell weight" of about 15lbs for AP rounds. I don't know if that includes the case and powder or not, and I'm not really sure how much an HE warhead would weigh. So lets just say that the loader on the B-25's is dealing with a 20lbs complete round.
For comparison: The loader in an the Abrams or Leopard tanks has a 120mm round to load. AP rounds weigh in at about 40lbs for a 1980's vintage round and about 55lbs for a current AP round. HEAT, MPAT, and Cannister rounds all weigh in at about 50lbs.
A loader in an Abrams tank is expected to be able to pull a round from the ready rack, turn it through 180 degrees so it faces the proper way, shove it in the breech, get himself clear of the recoil path, and arm the weapon, in under 10 seconds. Most loaders do so faster.
I would say that your B-25 loader could probably have his gun reloaded in under 10 seconds rather easily. Maybe even half that time. He has a lighter round to work with, and as his shells would be brass cased rather than combustible, he might be able to skip the steps of having to pull one from a rack for the first reload and instead simply have it sitting on his lap or held in his hands. ('Lap-loading')