The B-25 is a medium bomber, but it's also a small plane. I think it's max payload is 1500 (3x 500lb GP bombs) because I built a model kit once and that's all it could carry. Or maybe that was just a "typical" bombload. I don't know. LOL I better go check, brb
EDIT: Must have been 3x 1000lb on my model lol
Found a site that's talking about the -H (and the -J, which had all the features of the H, waist guns, dorsal moved forward, tail guns, etc etc.)
"Provision was made to carry three 1000 pound bombs rather than just two. Alternatively, two 1600-pound armor-piercing bombs could be carried. Provisions were made for the carrying of six 325-pound depth charges on underwing racks"
"Beginning with the 151st B-25J-1 (43-4019), provisions for the carrying of a single 2000-pound bomb were deleted. As it turned out, the 2000-pound bomb was rarely carried during actual combat, and the bulky and restrictive shackles for the 2000-pound bomb took up a lot of space in the bomb bay. This enabled a normal offensive load of two 1600-lb or three 1000-lb bombs to be carried internally, plus combinations of smaller bombs of various types, including 20-pound parafrags."
"Provisions were made for the carrying of wing-mounted T-64 zero-length rocket launchers beginning with 44-31338. These launchers could carry up to eight five-inch high-velocity aircraft rockets (HVAR). "
"The transparent nose for the bombardier could be replaced by a factory built solid gun nose that was equipped with eight 0.50-inch machine guns. With this modification, the aircraft was designated as B-25J-11, -17, -22, -27, -32, or -37, depending on which production block the modification took place. With its maximum armament of eighteen guns, the solid-nosed B-25J was one of the most heavily-armed attack aircraft in the Allied arsenal. Sometimes, however, the package guns on the sides of the fuselage were deleted, the remaining fourteen guns being more than enough."