Ammo per gun question?

The AN/M2 Brownings for the P-51 are stated to be between 750RPM and 850RPM, so I used the average of 800RPM.

I thought that the rounds per gun for the outboards were 270, and the two inboard were 380. So, the amount of time the outboards should be firing is 20.25 seconds, and the inboards at 28.5 seconds.

I made a quickie mission, and timed (at 1/16 through 1/32nd speed) how long the P-51's machine gun would fire. The outboards ran dry right in the mark, shortly after the time went past 20 seconds. However, as I held the trigger, the inboards went past 28.5 seconds. Then they went past 38.5 seconds. And finally stopped at a whopping 40 seconds of continuous firing, almost double the outboards. At 800RPM, this would require 534 rounds. Or more simply, 500 rounds at 750RPM.

 

So, does this mean that the four outboards are tuned to 800RPM, with a 270 round belts, while the inboards are at a slower 750RPM with 500 round belts? Was that normal?

Edited January 6, 2019 by Magic Zach
typo

Looking at the lua it seems that the guns are set up as-

left outer 270 rounds 798 rpm, left middle 270 rounds 800 rpm, left inner 500 rounds 803 rpm, right inner 500 rounds 797 rpm, right middle 270 rounds 801 rpm right outer 270 rounds 804 rpm.

 

 

No idea of correctness but particularly the numbers for rpm seem too exact to be approximations or coincidence so I would assume ED based the setup for ammo and rpm on a technical manual or reference.

Edited January 6, 2019 by Stonehouse

Looking at the lua it seems that the guns are set up as-

left outer 270 rounds 798 rpm, left middle 270 rounds 800 rpm, left inner 500 rounds 803 rpm, right inner 500 rounds 797 rpm, right middle 270 rounds 801 rpm right outer 270 rounds 804 rpm.

 

 

No idea of correctness but particularly the numbers for rpm seem too exact to be approximations or coincidence so I would assume ED based the setup for ammo and rpm on a technical manual or reference.

Shoot (hehe), I guess I somehow miscounted my seconds the first time around. I just went through it again a couple times, and not only I noticed now the right inboard fires an extra couple shots, they both stopped around 37.5 seconds. 500/800=.625, .625*60=37.5, cool beans.

Now that I knew what to look for, through a search I found that 500 rounds were used initially with the P-51. It was changed later, but this is an interesting find. 500 for the inboards, nice to know.

It was pretty common for the in most guns to have additional ammo on all the wing mounted mg aircraft. When all the guns stop firing except the inners, you know it's time to leave. Kind of like a 'backup magazine' to fight your way home.