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; 522742 views.
EmericD

From: EmericD

30-May

renatohm said:

What if you resort to higher pressures, but not NGSW high?

What barrel length are you comfortable with?

SIG's 6.8x51 mm pressure seems to be the price to pay for a 13" barrel instead of 19", or a 16" barrel instead of 22".

stancrist

From: stancrist

30-May

EmericD said:

       stancrist said: The question was not about terminal effects at 600 meters.  The question was about the need to engage at 600 meters.

The need for infantry to "engage" at 600 m (or up) is mostly a byproduct of the Rules of Engagement, but even with liberal RoE, the infantry needs to fix the enemy.

Okay, but I'm not seeing how that answers either of Nick's questions:

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

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

gatnerd

From: gatnerd

31-May

At the 12:45 we have FA testing of the SPEAR at 50yd; actually looks very good in terms of controllability and burst accuracy at that distance.

Sig MCX Spear - US Army NGSW - Disassembly, Live Fire & Discussion

InRange is entirely viewer supported:https://www.patreon.com/inrangeSpecial thanks to @illumined_arms for making this video possible! Please go check them o...

The 'flow-through' suppressor also seems to be working well; no gas to the shooters face, and pretty compact. 

stancrist

From: stancrist

31-May

gatnerd said:

FA testing of the SPEAR at 50yd; actually looks very good in terms of controllability and burst accuracy at that distance.

It does look pretty good.  Brass-cased (lower power) ammo, though -- not the full-power hybrid stuff.

gatnerd

From: gatnerd

31-May

Ah, great eye Stan. 

That brings up a pretty interesting feature; it seems like the Spear can fire both standard (62ish) pressure rounds, as well as the 80kpsi high pressure rounds. 

I wonder whether this requires changing the gas setting, and if there is a dedicated setting for both types of ammo? 

EmericD

From: EmericD

31-May

stancrist said:

Okay, but I'm not seeing how that answers either of Nick's questions: "How important is the need to engage enemy targets at 600 metres?" "How often will we need to engage enemies at this range?"

That just mean that depending on your RoE, engaging enemy targets at 600 m (or higher) could be rare and few (like during WWII & Korea), or up to one quarter (25%) of the infantry engagements (like Afghanistan).

That also mean that in the first case, issuing a DMR is probably sufficient to deal with those "rare & few" events, but in the second case you will probably need a NGSW.

gatnerd

From: gatnerd

31-May

EmericD said:

That also mean that in the first case, issuing a DMR is probably sufficient to deal with those "rare & few" events, but in the second case you will probably need a NGSW

Would a Full Power DMR & LMG paired with SCHV rifles be adequate for the 2nd scenario? 

For example NZ's configuration; 5.56 rifles (interestingly using 77gr) paired with a 7.62 DMR and 7.62 LMG:

To me, a similar configuration with NGSW seems better then a pure 5.56 or pure 6.8. 

6.8 LMG(s) and (optionally) 6.8 DMR, paired with 5.56 rifles for the rest. 

EmericD

From: EmericD

31-May

gatnerd said:

Would a Full Power DMR & LMG paired with SCHV rifles be adequate for the 2nd scenario?

The NZ weapon mix is very interesting.

80% equiped with 5.56 mm, 20% with 7.62 mm, and their DMR could be used full-auto, to provide limited long-range suppressive fire if necessary.

The team built around the 7.62 mm LMG could carry all the extra 7.62 mm ammo needed.

The Mk262 (from a 16" barrel) is delivering around 50% more KE at 600 m than the M855 (from a 14.5" barrel), providing better hit probability, but the impact velocity of ~410-420 m/s may fail to defeat LVL IIIA soft body armor.

Against unprotected opponents, this combination should be quite effective, at least on paper.

nincomp

From: nincomp

31-May

gatnerd said:

  I wonder whether this requires changing the gas setting, and if there is a dedicated setting for both types of ammo?

It is entirely possible that the same gas setting could be used for both.  What matters for rifle operation is the pressure in the barrel and characteristics of the pulse after the bullet passes the gas port.  With a given mass of propellant,  a faster burning rate will reach a higher maximum pressure sooner and transfer energy more quickly to a bullet.  This will leave less energy available in the form of pressurized gasses farther down the barrel at the gas port. 

The calculus changes a bit if SIG has managed to increase propellant energy density in the military cartridge somehow.  The general principle would remain the same but the total amount of energy would be larger.

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