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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NGSW Phase 2 Consolidation and info   Small Arms <20mm

Started 30/8/19 by gatnerd; 477584 views.
EmericD

From: EmericD

21/9/21

Mr. T (MrT4) said:

But AP485 is relatively oldfashioned AP with relatively large caliber penetrator

AP485 seems to use a tungsten (metal) core, DM151 is using tungsten carbide core, that could make a huge difference against ceramic...

smg762

From: smg762

21/9/21

Google '6.8CT' and theres a pic of black CT ammo which is clearly only 50mm long. And it says 762..

With a slight length reduction you could easily manage a 6mm CT for P90 mags, and with 40 rounds. 

Also the shrike by ares seems a good IAR...mags AND belt feed

EmericD

From: EmericD

21/9/21

smg762 said:

Google '6.8CT' and theres a pic of black CT ammo which is clearly only 50mm long. And it says 762..

The initial 6.5 mm and 7.62 mm ammo were 2" long by 1/2" in diameter, the current 6.8 mm is closer to 12 mm in diameter (7.62 mm case head), and longer.

gatnerd

From: gatnerd

21/9/21

EmericD said:

AP485 seems to use a tungsten (metal) core, DM151 is using tungsten carbide core, that could make a huge difference against ceramic

From what little I can find online (Nammo amunition handbook, some forum discussion) AP485 uses a Tungsten Carbide core. 

I was also under the general impression that pretty much all 'Tungsten' products, whether they be bullet cores or wedding rings or Rado watches or drill bits, were made out of Tungsten Carbide? WC being both harder and easier to sinter into parts then pure tungsten. 

gatnerd

From: gatnerd

21/9/21

smg762 said:

If CT ammo is short enoufhh to fit in a P90 style mag, it would make a great IAR....each guy could have 40 round mags. 

I think the best IAR ammunition style is SIG's, because high pressure thinwall metal cases allow for making very narrow cartridges. Which in turn would allow maximizing ammunition capacity.

Ideally, I'd love to see SIG's cases leveraged to produce a KEC 5.56 High Efficiency Cartridge , but using a more modern VLD projectile. You could have 50-60rd magazines about the length of a standard 30rd 5.56 magazine, while also being appreciably narrower, making them less bulky when mounted on a chest rig.

https://webcache.googleusercontent.com/search?q=cache:daKWoDnntFwJ:https://media.8kun.top/file_dl/d60e37c02cf77f03b6a279add542ef0b758a251d782461fc6b974fa4e21b1481.pdf+&cd=12&hl=en&ct=clnk&gl=us

The big question is whether 80kpsi of the SIG case design is enough pressure to make this little 5.56 straightwall replicate 5.56x45 velocity?

But if it were, a IAR using 50-60rd magazines of the 5.56 KEC would really be a fantastic Universal Infantry Weapon, creating a wonderful hybrid between a assault rifle and LMG. 

EmericD

From: EmericD

21/9/21

gatnerd said:

From what little I can find online (Nammo amunition handbook, some forum discussion) AP485 uses a Tungsten Carbide core. 

But from Buffman video, the bullet seems highly magnetic, and tungsten carbide is not magnetic at all.

gatnerd said:

I was also under the general impression that pretty much all 'Tungsten' products, whether they be bullet cores or wedding rings or Rado watches or drill bits, were made out of Tungsten Carbide?

It's more complicated... for example, the 7.62 mm SLAP is using a WC core (1400 Hardness Vickers), while the 12.7 mm SLAP is using a sintered W core (450 HV)...

stancrist

From: stancrist

21/9/21

smg762 said:

Google '6.8CT' and theres a pic of black CT ammo which is clearly only 50mm long. And it says 762..

You asked about 6.8 CT, not 7.62 CT.  And 6.8 CT is clearly much longer than 50mm.

smg762 said:

With a slight length reduction you could easily manage a 6mm CT for P90 mags, and with 40 rounds.

6 CT case size would depend upon what bullet weight and muzzle velocity you want.

A 95gr or heavier 6mm EPR bullet would be longer than the 7.62 M80 ball projectile.

Below, 6mm lead-core 95gr VLD

As a result, a 6 CT cartridge would probably be at least 50mm long.

It could be smaller diameter, though.  I'd estimate ~0.44" diameter.

Which makes a 40-rd mag be about the same length as a P90 mag.

However, you would still have the other issues that I noted before.

Mag changes in the prone position look difficult, if not impossible.

Minimal rail limits optics that can be used.  No NVS or NGSW FCS.

And then there's the matter of loading P90-type magazines. 

What a pain in the arse.  Soldiers would curse you forever!

https://youtu.be/4Ttmu-AWudE?t=15

Compare that to this:  https://youtu.be/9dujUDYn-18?t=5

  • Edited 21 September 2021 16:08  by  stancrist
stancrist

From: stancrist

21/9/21

Reliability of feeding, chambering, extraction with such an extreme L:D, and zero case taper?

smg762

From: smg762

21/9/21

My new thought for a 'ultimate' LMG is something as light as a SAW but with extreme penetration. Either a 6mm unified or a saboted 4.5mm with the same energy.

Could the CT arrangement allow for a more extreme AR2 shape?

The KEC sounds good. Am i right in thinking a slam and go gun, means that you can literally jam in a belt box without messing around with links?

And does anyone have opinions on the Ares shrike style of 'dual feed'.....both belts and mags in one light package

  • Edited 21 September 2021 15:13  by  smg762
VPMudde

From: VPMudde

21/9/21

I've been ruminating on the supposed 6.8mm magnum projectiles and their trajectories.

The following is an estimate for the projectile made from images available online

5 caliber bullet, 2.5 cal nose cone, 0.1 cal meplat, 0.8 cal 7° boat tail, secant ogive radius = 2x tangent ogive radius.

With a density of 8.5 g/cm3 (Pb-free EPR) it comes in at 123.7 gr. Seems a little light, in light of the supposed 135 gr bullet weight. Even solid copper in this shape only comes in at 129.5 gr.

Does that mean that the 135 gr figure is only for the AP variant (due to the use of tungsten)? And that the GP projectile is actually a fair bit lighter than AP? Or am I wrong about this shape? 

Now I know this tool is a bit generous with BC at times, but considering that this bullet isn't 135gr yet I'll take the 0.26 G7. At 915m/s it's not a bad trajectory at all. 1 second to 700m,  800+ joules out to 900m, supersonic out to over 1100m. 

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