gatnerd

Military Guns and Ammunition

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This is intended for people interested in the subject of military guns and their ammunition, with emphasis on automatic weapons.

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Aeroshell AP Bullet developed by SOCOM   Ammunition <20mm

Started 1/9/19 by gatnerd; 2905 views.
gatnerd

From: gatnerd

1/9/19

SOCOM is reportedly working on a new style of AP projectile:

https://www.armytimes.com/off-duty/gearscout/kit/2019/06/11/socom-wants-a-new-armor-piercing-sniper-bullet-heres-one-option-engineers-are-developing/

Dubbed “aeroshell” projectiles, the Crane engineers want to build and test bullets with a tungsten penetrator jacketed in a polymer shell.

Researchers plan to create about 150 rounds of this new aeroshell AP round in .338 Norma Mag, 300 Norma Mag and 6.5 Creedmoor. They plan to test the rounds against representative body armor at 100, 400, 800 and 1,000 meters.

 

This is a pretty exciting development. It potentially offers a best of both worlds between Sabot's and conventional projectiles. It allows for the accuracy and high BC projectile shape of a conventional bullet, while like a sabot, it offers maximum penetrator weight relative to projectile weight and increased velocity. 

For example, a 130gr M993 has a 90gr Tungsten core. 

If the copper were replaced with polymer, it could end up being a 90gr core with a 10gr jacket - same AP core weight, but with a much higher velocity. 

Unlike sabots, which are typically restricted to short, stubby projectiles with poor BC, this Aeroshell will allow for VLD shapes with full length cores. This will not only improve projectile ballistics, but increasing core length will also increase penetration. 

renatohm

From: renatohm

1/9/19

APCR reborn?

autogun

From: autogun

1/9/19

Not very different in design to the RUAG 7.62 X 51 HC (formerly developed by Anthena of France) except that the materials are different: https://www.ruag.com/sites/default/files/2016-12/High_Performance_Infantry_Ammunition_en.pdf

The problem with the bullet retaining its sabot in flight is that it has a larger calibre and higher drag compared with APDS, so loses velocity faster (OTBE). However, it might prove to be an acceptable compromise, provided tungsten stocks hold up...

.

EmericD

From: EmericD

1/9/19

autogun said...

Not very different in design to the RUAG 7.62 X 51 HC (formerly developed by Anthena of France) except that the materials are different: https://www.ruag.com/sites/default/files/2016-12/High_Performance_Infantry_Ammunition_en.pdf

The problem with the bullet retaining its sabot in flight is that it has a larger calibre and higher drag compared with APDS, so loses velocity faster (OTBE). However, it might prove to be an acceptable compromise, provided tungsten stocks hold up...

The difference with this design is that the bullet is spin stabilized, with the core made with high density compounds and the "jacket" is a low density compound, so the bullet will need a very fast twist for its L/D ratio. Or, for a given twist, you can't use a L/D as high as a more conventional design.

In reply toRe: msg 4
Refleks

From: Refleks

1/9/19

I thought polymer interfaces with rifling caused significant fouling?  Or will it have a light jacket wash?

  • Edited 01 September 2019 16:53  by  Refleks
gatnerd

From: gatnerd

1/9/19

"Not very different in design to the RUAG 7.62 X 51 HC (formerly developed by Anthena of France) except that the materials are different: https://www.ruag.com/sites/default/files/2016-12/High_Performance_Infantry_Ammunition_en.pdf"

It's similar in that it uses a full length penetrator with exposed tip, which is really how AP projectiles should be constructed.

However the change is material is quite significant. From previous reading, the RUAG 148gr 7.62 HC is reportedly 60% penetrator by weight, which makes 40% of the projectile formed by the copper shoe parasitic weight. 

148gr

60% = 89gr

40% = 59gr 

 

Copper = 8.96g cm3

Ultem 1000 plastic = 1.28g cm3

=14% the weight

-->59gr x .14 = 8.26gr

----> Aeroshell HC = 98gr

-------> Substantial increase in velocity. 148gr = ~2750fps. 98gr = 3400fps+

To further put this into perspective, the core weight of the .30-06 M2AP is 80gr:

So a 7.62 98gr Aeroshell AP @ 3400fps = M2AP @ 3400fps in terms of potential penetration. 

By comparison, even .300 Remington Ultra Mag (far right) tops out at 3,300fps for a 168gr:

Overall this represents a significant evolution in the AP viability of steel core, as well as tungsten.

7.62 AP FN = 150gr / 59gr core @ 2750fps

7.62 RUAG HC = 148gr / 89gr core @ 2750fps

7.62 Aeroshell = 98gr / 89gr core @ 3400fps

"The problem with the bullet retaining its sabot in flight is that it has a larger calibre and higher drag compared with APDS, so loses velocity faster (OTBE). However, it might prove to be an acceptable compromise, provided tungsten stocks hold up..."

It will be interesting to see; I know current 7.62 SLAP uses a very short bullet with a terrible BC:

Whereas the Aeroshell will allow the use of VLD shapes with a proper boat tail and ogive. 

  • Edited 01 September 2019 20:20  by  gatnerd
gatnerd

From: gatnerd

1/9/19

"The difference with this design is that the bullet is spin stabilized, with the core made with high density compounds and the "jacket" is a low density compound, so the bullet will need a very fast twist for its L/D ratio. Or, for a given twist, you can't use a L/D as high as a more conventional design."

Do you have any estimation on what type of twist would be required, or how much L/D would have to be reduced?

gatnerd

From: gatnerd

1/9/19

"I thought polymer interfaces with rifling caused significant fouling?  Or will it have a light jacket wash?"

I'm not sure if thats the case:

Of the complaints with sabots, I don't recall fouling being one. And autocannons are using polymer driving bands. 

Red7272

From: Red7272

1/9/19

Refleks said...

I thought polymer interfaces with rifling caused significant fouling?  Or will it have a light jacket wash?

Not for a very long time. Plastic driving bands have been a thing for artillery and autocannons for a couple decades now.

PRM2

From: PRM2

2/9/19

Would a very fast twist barrel have to be the same twist along the whole length, or could it just "spin up" the projectile close to the muzzle. If this could be done with a muzzle attachment or quick change barrel (eg. Steyr AUG, Stoner 63 or most LMGs), it could also allow trained personnel to cater for a range of weapon/ammunition combinations.  

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