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Neckless ammo   Ammunition <20mm

Started 20/8/21 by EmericD; 41487 views.
EmericD

From: EmericD

20/8/21

Mr. T (MrT4) said:

Very cool to see these kinds of experiments, i am still holding off on pushing my 6mm to such an extremely short neck , would be interested to see any data on velocity ES ,SD of such no neck cartridge.

It's not a viable option for large-scale production, the final round should look like a scaled-down 6.8 mm TVCM.

gatnerd

From: gatnerd

20/8/21

EmericD said:

The idea was to scale-down a variant of the 8 mm Lebel "Balle D" (with a slightly secant ogive) and mate this bullet with a 5.56x45 mm case with a neck shortened to ~40 mm (virtually no neck left). First comment, we used regular IMI 5.56 mm NATO round, pulled the bullet out, removed the powder load (1.66 g of ball powder), removed the neck, put back the powder and the new bullet, then find a way to crimp the cartridge. Good news, the modified case volume vas enough to keep the orignal powder load, even with the very long (26.9 mm & 63.7 gr) 5.56 mm Balle D. We fired those rounds out of a Remington bolt action rifle with a 24" barrel. Muzzle velocity was 963 m/s, and the recorded i7 form factor was 0.84, which is exactly the form factor of the 8 mm version (the i7 of the original "Balle D" is 0.90, but the current version made by TPM is using a slightly secant ogive nose and the FF is 0.84). So I was wrong, there seems to be no penalty for such small bullet, and its G7 BC is 0.216.

Wonderful test and news! This is so exciting, and the results sound great. If this all comes to fruition you will have seriously evolutionized the 5.56 and its future capabilities. 

Couple questions.

-What was the solution for crimping? Were the bullets glued in the case? 

-Is the crimp durable enough in the brass configuration that it could be used in military applications, or does this really need a polymer, mini TV configuration? 

-How was the bullet made? And does there look to be a viable path forward for making these 'mini D's' economically at scale? 

In reply toRe: msg 10
gatnerd

From: gatnerd

20/8/21

Heres a couple chart how regular 62gr M855 compares to the 64gr Neckless from the M4. 

Ballistics Snap shot:

300m Velocity and Energy: M855 (1992fps/546) vs Neckless (2216fps/698ftlbs)

Distance to 1700fps: M855 (400m) vs Neckless (562m) 

600m Velocity and Energy: M855(1224fps/206) vs Neckless (1631fps/378)

Supersonic (1125fps) Range: M855 (649m) vs Neckless (842m) 

M855:

64gr Neckless:

stancrist

From: stancrist

20/8/21

EmericD said:

900m+ supersonic range and 80% more KE at 600 m compared with M855.

Outstanding!

P.S.  What is the "penalty" you alluded to in the OP?

  • Edited 20 August 2021 11:41  by  stancrist
JPeelen

From: JPeelen

20/8/21

I would not say you were "wrong". As my plot of i7 data published by Bryan Litz shows, 5.56 mm bullets (red dots) in general have higher i7 values than 7.62 mm bullets (blue dots) of the same length/diameter ratio. In my view, it was very reasonable to expect a somewhat increased form factor from scaling down the bullet. Looks as if the balle D shape really stands out.  

Edit: I found no way to prevent the software from shrinking the much larger graphic to unreadability. Sorry. 

  • Edited 20 August 2021 12:08  by  JPeelen
EmericD

From: EmericD

20/8/21

gatnerd said:

Couple questions. -What was the solution for crimping? Were the bullets glued in the case?  -Is the crimp durable enough in the brass configuration that it could be used in military applications, or does this really need a polymer, mini TV configuration?  -How was the bullet made? And does there look to be a viable path forward for making these 'mini D's' economically at scale? 

A special tool was needed for crimping without risking to change the shoulder angle and stay safe. Don't try to do this at home!

I think that the brass version, as shown here, is not viable (but maybe someone wiser than me will manage to do it) and that we need a "mini TV" configuration. And the "mini TV" will also save 1 kg out of 300 rounds.

The bullet was lathe-turned, for large production we will need to cold press it, the same way the Mle1898D bullet was made. That will be another "working package", but I wanted to check the bullet flight first.

EmericD

From: EmericD

20/8/21

stancrist said:

P.S.  What is the "penalty" you alluded to in the OP?

The current brass case is impractical so I need a TV case which does not exists... I hope that the increase of the propulsive efficiency will balance the reduction of internal volume.

EmericD

From: EmericD

20/8/21

JPeelen said:

I would not say you were "wrong". As my plot of i7 data published by Bryan Litz shows, 5.56 mm bullets (red dots) in general have higher i7 values than 7.62 mm bullets (blue dots) of the same length/diameter ratio. In my view, it was very reasonable to expect a somewhat increased form factor from scaling down the bullet. Looks as if the balle D shape really stands out.

I have another radar test planned with a tracking radar, this one will give me a more definitive answer for the whole flight range!

I wrote that I was wrong because I previously (last March) tested a 5.56 mm bullet shape proposed by Nathaniel, and the measured form factor was far from the calculated 0.75 i7.

In .408", the difference between the computed value and the experimental value was nearly zero (0.47 G7 BC vs. 0.468 measured), in .338" there was a small difference, a larger difference in .308" and a full 13% of difference in .224". I falsely concluded that it was a scaling problem.

gatnerd

From: gatnerd

20/8/21

EmericD said:

I think that the brass version, as shown here, is not viable (but maybe someone wiser than me will manage to do it) and that we need a "mini TV" configuration. And the "mini TV" will also save 1 kg out of 300 rounds. The bullet was lathe-turned, for large production we will need to cold press it, the same way the Mle1898D bullet was made. That will be another "working package", but I wanted to check the bullet flight first.

Excellent, thanks for that info. 

Have you had any contact with TV? Especially if NGSW does not work out, I think they'd be extremely interested in this project. 

In terms of Cold Forming, that to me is almost as exciting as the Neckless project. If a method is developed to create these very fine, VLD lead free projectiles economically, that would go along way toward making VLD military ammo a reality. As well as generally being very positive for recreational shooting. 

Were the bullets brass or copper? 

And what would a 6mm version look like in terms of weight / estimated BC? 

Curious how the modern Balle D shape stacks up vs the 6mm Flatline. 

gatnerd

From: gatnerd

20/8/21

JPeelen said:

I found no way to prevent the software from shrinking the much larger graphic to unreadability. Sorry. 

For sharing images on this forum and others, I've had great luck using:

https://imgbb.com/

It will upload your pic and turn it into a full size image thats shareable via a link, which can be copied into the 'upload from web' part of this forums image software.

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