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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; 554032 views.
gatnerd

From: gatnerd

29/5/22

Guardsman26 said:

It appears that SOCOM shares this view. And we are NOT talking about standard 6.5 mm Creedmoor - we are talking about a new specification based on that cartridge fired at a higher chamber pressure so it delivers increased penetration out of shorter barrels.

I mean, if its a meaningfully higher pressure 6.5C (65-70kpsi) then its realllly getting to a near pointless distinction vs 6.8 NGSW in terms of benefits.

-Comparable/identical weapon weight

-Identical ammo loadout / magazine capacity / belt capacity 

-Identical cartridge volume 

-Still High recoil 

-Higher heat and wear then 7.62 due to increased pressure and narrower swept bore volume 

....

MAC LLC's polymer ammo has a brass base (the heaviest part of the cartridge), making weight savings pretty marginal. 

If SIG's 6.8 is 22gr, the polymer 6.5 would need to be 18.75g in order to shave off 1lb from a 140rd (7x20rd mag) loadout vs 6.8. Itself a rather meh improvement. 

I don't really see 6.5C/6.5SP as much if any of an improvement. If anything it just seems like having all the drawbacks of NGSW with less performance. 

stancrist

From: stancrist

29/5/22

Guardsman26 said:

NGSW presents several critical disadvantages: 

* 7.62x51 mm size case  

* It also introduces significant recoil, making automatic fire more difficult to control.

* 6.8x51 mm reduces the amount of ammunition that can be carried for a given weight - this reduces hit probability

* Overall system cost is likely to be significantly greater even before you add the XM157 FCU optic and integral suppressor

* Overall system increases the logistics burden

* Overall system increases the training burden 

* Overall system increases the dismounted soldier's weight burden

* All of this extra long-range performance comes at the expense of 0-300 metres performance - and still this remains the critical range envelope

The trouble is, all of the above disadvantages are also true of 6.5 Creedmoor guns and ammo.

Guardsman26 said:

The question raised by 6.8x51 mm NGSW is how important is the need to engage enemy targets at 600 metres? And do the benefits of being able to do so outweigh the clear disadvantages? How often will we need to engage enemies at this range?

As I recall, not too long ago GPC proponents in this forum were arguing that it was very important to be able to engage the enemy at 600-plus meters, and they insisted that the benefits very much outweighed the disadvantages.

Guardsman26 said:

For these reasons, I believe we need NGSW to have a lesser requirement - arguably to defeat body armour to 300 metres. This will result in an ammo that is more capable than 7.62 mm, but lighter, and without the cost and logistical issues of 6.8 mm NGSW ammunition. 

I agree.  Actually, I'm inclined to think that armor defeat range could be reduced to circa 100 meters.

Guardsman26 said:

Let's call SOCOM's 6.5 mm round 6.5 mm Creedmoor SP.  Is it optimised to blanche the conflicting requirements for NGSW? No. Because it still reduces the number of rounds carried for a given weight. Would I prefer a 6 mm round fired at the highest possible velocity in the smallest possible case? Yes. But, if the requirement demands Level IV defeat, and this mandates 6.5 or 6.8 mm, we may have to accept certain disadvantages.  What we can't do is destroy logistical efficiency, increase the training burden, increase the weight burden by adopting a more expensive weapon with more expensive ammo and that has a shorter life.

Except for the expensive ammo, it seems to me you'll also have pretty much all of those issues with 6.5 CM SP. 

Since the 6.8x51 weapons have already been developed, I am not sure that switching to 6.5x48 now is worth it.

Apsyda

From: Apsyda

29/5/22

There is utility in the GPC idea. But not in the form of making a smaller battle rifle cartridge. The Russians were onto the right idea back in the 80s/90s.  

6mm diameter, 77gr projectile at 3700FPS muzzle velocity.

That to me does a lot better at stepping up the power and range of the 5.56NATO, without getting to the point of excessive recoil. A lighter bullet going faster is easier on the shooter than a heavier bullet going slower. And modern metallurgy should keep us out of the undesirable barrel wear zone for longer.

A 100yrd penetration requirement is reasonable, I'd agree there.

renatohm

From: renatohm

29/5/22

If I recall correctly, GPC never had the goal of defeating body armor at enormous distances, most people here said that GPC was to be accurate and effective enough to pin down the enemy so that HE could do the job.

Emeric uses the 'suppression index' (or something like that) for the 'effectiveness' part. Maybe I'm wrong but body armor or not, if you are being (almost) hit by pills that can do more than a paper cut you're pinned down, and troops carrying HE can finish the job.

If you can pin down the enemy (relatively) far away then you have the additional option of calling the big guns.

stancrist

From: stancrist

29/5/22

renatohm said:

If I recall correctly, GPC never had the goal of defeating body armor at enormous distances...

That's true, but his questions are:

"How important is the need to engage enemy targets at 600 metres?"

and

"How often will we need to engage enemies at this range?"

stancrist

From: stancrist

29/5/22

Apsyda said:

The Russians were onto the right idea back in the 80s/90s.  

6mm diameter, 77gr projectile at 3700FPS muzzle velocity.

heart_eyes  heart_eyes

Guardsman26

From: Guardsman26

30/5/22

Assuming it had a bullet made of hardened steel, a 6x49 mm cartridge with a 80-90 gram projectile fired at 3,500-3,700 fps would have no problem punching a hole through body armour above 300 metres. 

Stan, I think you have missed my point about the logistics of 6.5x48 mm Creedmoor ammunition versus the logistics of 6.8x51 mm NGSW. I estimate that the latter system will cost 30-40% more than 6.5x48 mm Creedmoor. 10% would be significant, but anything above 20% will kill NGSW. 

graylion

From: graylion

30/5/22

Guardsman26 said:

Assuming it had a bullet made of hardened steel, a 6x49 mm cartridge with a 80-90 gram projectile fired at 3,500-3,700 fps would have no problem punching a hole through body armour above 300 metres. 

what could be achieved with ~550 MPa?

EmericD

From: EmericD

30/5/22

Apsyda said:

6mm diameter, 77gr projectile at 3700FPS muzzle velocity.

If I recall correctly, this MV was achieved in pretty long barrel, around 72 cm / 28.3" in length.

Fire that cartridge from a 16" barrel and the ballistics will be less impressive.

renatohm

From: renatohm

30/5/22

NGSW goal is not to merely hit at 600 meters, it is to hit a target with enough energy to defeat body armor at such a distance.

Replace the ridiculous 'body armor defeat @ 600 m' to 'hit an unarmored target at 600 meters with lethal force' and you get very close to GPC.

As for the second part - how often do you HAVE to engage targets at 600 meters - I honestly don't know. My guesstimate is 'not often enough'.

Maybe something like 5.8x42 would be enough?

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