Post-War 20mm Ammunition Weight Question

[Zipper730]

I'm not sure if this should be put on Post-War, Modern-Era, or Technical because the Technical specs is largely for WWII related stuff, and the Crusader served in Vietnam, but I don't know if the Tiger did.

I was looking through the standard aircraft charts for the F11F (here) and F8U, and I found something kind of odd: Both aircraft have 4 x Colt Mk.12's with 125 rpg. As a result, one would assume their ammunition would weigh exactly the same, and yet from data listed on the F11F and data extrapolated from two sources (here, and here) on the F8U show the Tiger with 300 pounds for 500 rounds, and the F8U showing 327 for 500 rounds.

What's with the discrepancy?

M MIflyer , S Shortround6 , T tyrodtom , X XBe02Drvr

 

[XBe02Drvr]

from data listed on the F11F and data extrapolated from two sources (here, and here) on the F8U show the Tiger with 300 pounds for 500 rounds, and the F8U showing 327 for 500 rounds.

What's with the discrepancy?

Don't know this gun, but same gun installed differently in different aircraft is apt to have differences, such as linkbelt feed vs drum feed, etc.

 

[MIflyer]

Possibly a different mix of ball, explosive, API, tracer. Some aircraft have been known to be armed with ball, non-exploding 20MM rounds, presumably for safety purposes. When a Mace missile got away from the Eglin AFB range in the mid-60's, the F-4 detailed to shoot it down had ball ammo, which might be fine for marking a target for accuracy tests but were inadequate to shoot down the missile, which overflew Cuba before coming down in the ocean.

 

[XBe02Drvr]

When a Mace missile got away from the Eglin AFB range in the mid-60's, the F-4 detailed to shoot it down had ball ammo

If it was an F4 in the mid 60s toting a gun, it had to have been a pod mounted one, which would have been near useless for air-to-air gunnery. IIRC, the nose gun E model didn't show up til 1969.

 

[Zipper730]

Okay so the differences in whether you have a link-belt feed versus a drum-feed, and the different mix of projectiles?

 

[Zipper730]

If it was an F4 in the mid 60s toting a gun, it had to have been a pod mounted one, which would have been near useless for air-to-air gunnery. IIRC, the nose gun E model didn't show up til 1969.

I thought the F-4E first flew in 1965, entered service in 1967?