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Can anybody tell me what the muzzle velocity is for the 30mm? Exterior Ballistics is one of my hobbies.


"The First Rule in a Gunfight: Have a gun. If you violate this rule, no other rules apply" Jeff Cooper

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Can anybody tell me what the muzzle velocity is for the 30mm? Exterior Ballistics is one of my hobbies.


"The First Rule in a Gunfight: Have a gun. If you violate this rule, no other rules apply" Jeff Cooper

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Really, really fast. One might even call it 'Ludicrous Speed.'




ATTACK!

Edited by - AIR2MUD on Mar 31 2003 07:25 AM

3,500fps.

"I Am Infantry...Follow Me!!!"

I tried figuring the Kinetic Energy of a 15 oz. bullet at 3500 fps, but my program doesn't allow entries that large! Anyone already have that number handy?


"The First Rule in a Gunfight: Have a gun. If you violate this rule, no other rules apply" Jeff Cooper

This is how you do it manually.

Multiply mass(in grains) x velocity squared, divided by 7000(that's how many grains per pound), divided by 2, divided by 32.16(atmo pressure at sea level).

So it's 6562 grains, x 12,250,000(vel. sqrd), divided by 7000, divided by 2, divided by 32.16

Answer.... 178,537 foot pounds of KE.

That formula works for any object with a known mass and speed.

"I Am Infantry...Follow Me!!!"

Snipe - standard atmospheric pressure at sea level is 29.92 inches Hg. That figure drops by 1 inch per thousand feet of altitude gained, i.e. standard press at 1,000 feet MSL is 28.92 in. Hg.

32.16 would be obscenely high. In fact, most civilian aviation is grounded when the pressure exceeds 31.00 in. Hg., due to pitot static limitations I believe. The world record for sea level equivalent pressure was recorded in Siberia at 1200 GMT on 31 December 1968: 32.01 in. Hg. Since the station is at 854 feet above sea level, the actual recorded pressure would have been 31.16 in. Hg. if they were using the standard one inch per thousand feet lapse rate.

Maybe I misread your post?

If it was a typo on your part, I ran the numbers again - 191,903 ft/lbs KE @ sea level on a standard day.

~Thud

32.16 represents the mathematical equation figure for atmo @SL, it is not the rating in PSI, in-Hg, or KgP. I admit though, i have no idea what it represents exactly.

That is definitely the right figure though Thud.



"I Am Infantry...Follow Me!!!"

Edited by - m21 sniper on Mar 31 2003 10:36 AM

That 32.16 number looks like the conversion to mass units, sometimes refered to as "g sub c", the accel of gravity. Remember that mass unit you used in school called slugs? Well, this converts pounds to slugs (crazy units of lb-sec2/ft). It has nothing to do with atmospheric pressure.

Mc/I + P/A

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I don't think so A-10, because the /by 7000 part of the equation is what represents mass. Perhaps mass changes with pressure?
I dunno, but i do know that if you don't figure in the 32.16(ie in a vacuum) the number is way off- whereas if you do it will match the exact figures given for known loads by the manufacturer.

I think it is supposed to represent the drag induced by air density.

If anyone finds out for sure, lemme know.

"I Am Infantry...Follow Me!!!"

I thought 32.16ft/sec^2 was the acceleration due to gravity, which is equivalent to 9.8meters/sec^2

--Raven

"For democracy, a man would give his only begotten son."

Thanks for the replies. My question got answered well enough. I'm building a display for the next gunshow around an intact TP round; photos, tables, etc. I'm focusing on the Avenger (but including a lot of info on the Aircraft) because it IS a gunshow. Does anybody have a complete full-size Avenger Static Display that I could borrrow?


"The First Rule in a Gunfight: Have a gun. If you violate this rule, no other rules apply" Jeff Cooper

I just got some good pix of the Avenger living in the belly of a Hog, thanx to one Air2Mudd.

"I Am Infantry...Follow Me!!!"

[quote]
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32.16 would be obscenely high. In fact, most civilian aviation is grounded when the pressure exceeds 31.00 in. Hg., due to pitot static limitations I believe. --------

I launched one time out of Norva and it was 31", really weird and cold day. It might had been higher one of those weird days you remember and coming back below FL180, you were dicking around for altitude. Might had been higher pressure too. My ears were hurting on the deck.

Jack