This is intended for people interested in the subject of military guns and their ammunition, with emphasis on automatic weapons.
Latest 17:32 by stancrist
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Latest 29-Aug by EmericD
Going back to the SIG NGSW Rifle, I did a little weight estimations.
SSD lists the weight as 8.1lbs, with a 13" barrel. That is without optic or suppressor.
SIG NGSW Weight:
SIG SRD762 Suppressor = 1.0625lbs
Steiner ICS Optic = 1.74lbs
PEQ 16 w/ Batteries = 11.1oz / 0.694lbs
7.62 20rd PMAG = 5.5oz/0.344
6.8 ngsw = 19.2g (assuming 20% less weight then 130gr 7.62)
x20 = 0.847lb
1x20rd mag = 1.19lbs
SIG NGSW = 11.6lbs empty / 12.79lbs loaded
So, good news is, recoil is less likely to be an issue.
Bad news is, it's pretty heavy:
ACOG TA31 RCO= 16.2oz /1.1lbs
M4A1= 8lbs unloaded / 9.1lbs loaded
'M4A2' = 6.5lbs
PEQ 16 = 0.563lbs
Sig Tango 6 1-6x = 25.4oz / 1.5875
Gesselt scope mount = 0.45lb
M4A2= 9.1lbs unloaded / 10.1lbs loaded
Good weight tabulation. I am still amazed by the "all up" weight of M4 variants, but I guess that's because my military service was with the M1 carbine and M16A1 rifle.
Question on the 6.8 NGSW cartridge weight: Why assume 20% less than 7.62 M80A1? I'd think there would be negligible difference, since the 6.8 bullet is 5 gr heavier.
If it does take box mags, will it be more reliable than the M249 with box mags?
"Good weight tabulation. I am still amazed by the "all up" weight of M4 variants, but I guess that's because my military service was with the M1 carbine and M16A1 rifle."
Yes, once you start adding accessories weight definitely goes up. My personal rifles, its quite noticeable at first the change between what came out of the box, vs what it weighs with optic / light / sling. On the other hand, once you get used to it, its less noticeable.
Looking at weight of accessories, it does show the advantage of starting with as light a base rifle as practical.
"Question on the 6.8 NGSW cartridge weight: Why assume 20% less than 7.62 M80A1? I'd think there would be negligible difference, since the 6.8 bullet is 5 gr heavier."
I was being charitable, giving a best case.
But I agree with you, I expect SIG's offering is going to be pretty close / identical to existing 7.62 Brass. The projectile is about the same, the case is about the same, its likely to have a bit more powder then 7.62, and I just can't figure out how a Steel + Brass case is going to be much lighten then a regular brass or steel case.
"If it does take box mags, will it be more reliable than the M249 with box mags?"
On the one hand, this and the .338 its based on are SIG's first real machine gun design. Whereas FN had decades of MG experience and still had issues with the M249 when it was introduced.
On the other hand, modern firearms are now designed with sophisticated computer programs that allow running various simulations of the action / stress analysis / myriad other tests. So its possible the SIG LMG has a really good design right from the get go.
In general, based on their pistols and rather notorious QC issues with their civilian weapons, I'm skeptical of SIG.
True Velocity is now showing off their 6.8 NGSW Cartridge:
True Velocity composite-cased ammunition has been selected for the U.S. Army’s Next Generation Squad Weapon (NGSW) modernization program. True Velocity’s 6.8mm composite-cased cartridge was submitted as part of an overall NGSW weapon system in partnership with General Dynamics Ordnance and Tactical Systems and firearm manufacturer Beretta Defense Technologies.
True Velocity’s proprietary 6.8mm case design will provide end users with significant logistical and operational advantages over traditional brass-cased ammunition, including substantially increased effective range and muzzle energy, drastic reduction in cartridge weight and enhanced accuracy. The combination of True Velocity’s ammunition with the General Dynamics OTS weapon submission results in a state-of-the-art weapon system capable of long-range lethality, short recoil impulse, significant ballistic improvements and enhanced operational effectiveness for the soldier.
“True Velocity’s 6.8mm composite case design produces a level of performance, consistency and efficiency never before seen in small arms ammunition,” said Chris Tedford, president and chief operating officer for True Velocity. “Combining True Velocity’s innovation and technology with the expertise of General Dynamics OTS and Beretta results in a weapon system solution that exceeds NGSW requirements and provides the U.S. Army with a definitive edge on the field of battle.”
Is beretta doing for GD what HK is doing for Textron?
And the foto is really interesting. What a tiny shoulder!
It is actually very much like the 7.62x43 neck-less round on pages 117 and 118 in Emeric's "Towards a "600 m" lightweight General Purpose Cartridge, v2019, Full Paper."
A few years ago I was very proud of myself for thinking up a neckless polymer round that could be used in weapons designed for traditional metallic cartridges. When I discussed it on this forum, Emeric posted that it already existed but he couldn't talk about it until the patents were granted. At least I knew that I had an idea that wasn't stupid, for once. I just had it too late.
Emeric, do you need to sue?
This looks very similar to something he showed us years ago. Polymer case with a thickened shoulder that was glued to the projectile. It would make long ogive version of existing round possible.