New Cartridge Developments and Implications for Dismounted Infantry Soldiers

[LRRPF52]

LSAT is select fire and can easily be shot with controlled pairs with simple trigger discipline like any other constant recoil system. We already have been taking SAWs into the house since the SAW was adopted, it just traces in the Fire Team because of the drag it causes a soldier with all that weight. LSAT takes that away, so you aren't as concerned about who is in the Fire Team flow.

The ammo cost and ability of soldiers to carry so much more ammo will change things.

The biggest obstacles are going to be South Carolina Congressional districts with the FN manufacturing plant.

That USMC rotary grenade launcher is garbage by the way. Major reliability problems and complications with reloading them. They don't work in a field environment very well, but have been kept us truck grenade launchers by units who have access to them. For dismounting, they were a major failure.

[cory]

...We already have been taking SAWs into the house since the SAW was adopted,...

Please don't remind me of this s***. HAHA

I'd rather clear a room with 2 known tangos with an M4, than clear a room that might have and might not have a tango, with the SAW. Going into a room I'd fully expect to be using the SAW as a club. They were bad enough about not firing when you pulled the trigger especially then moving as violently as you do moving through a house, forget about it.

Not to mention that, at least when I was in, it was a rule that the SAW gunner was never the 1 man (didn't enter the room first), because of its lack of reliability.

Sorry about the slight tangent, back to a caseless 130gr .510+ BC combat load.

[Variable]

LSAT is select fire and can easily be shot with controlled pairs with simple trigger discipline like any other constant recoil system. We already have been taking SAWs into the house since the SAW was adopted, it just traces in the Fire Team because of the drag it causes a soldier with all that weight. LSAT takes that away, so you aren't as concerned about who is in the Fire Team flow.

The ammo cost and ability of soldiers to carry so much more ammo will change things.

The biggest obstacles are going to be South Carolina Congressional districts with the FN manufacturing plant.

That USMC rotary grenade launcher is garbage by the way. Major reliability problems and complications with reloading them. They don't work in a field environment very well, but have been kept us truck grenade launchers by units who have access to them. For dismounting, they were a major failure.

Just funning.

I couldn't help it once Cory put a vision in my head of everybody having a beltfed with a 1000 rounds of ammo....

Sorry about the slight tangent, back to a caseless 130gr .510+ BC combat load.

Ditto. That would rock!

[stanc]

Sorry about the slight tangent, back to a caseless 130gr .510+ BC combat load.

Ditto. That would rock!

Yeah, but question is, is such a military ball projectile feasible to make?

Swedish lead-core, 6.5mm Ball weighs ~140gr, and has a fairly high length to diameter ratio (L/D ~4.9).




The steel-core AP looks to be identical in L/D, but weighs only 112gr, considerably lighter than the hypothetical 130gr bullet.




And don't forget, it'll be necessary to also develop a companion Tracer, which typically are longer -- and often lighter -- than Ball rounds.

[cory]

I don't understand why we need an AP rifle round.

Or why the tracer would be a consideration at this point. We'll shape the tracer to best fit the best possible combat bullet. Speaking of which has the 5.56 tracer been modified since the M193 was developed?

[stanc]

I don't understand why we need an AP rifle round.

I wasn't clear. I mentioned the Swedish 6.5mm AP bullet only because its steel core construction makes it weigh about the same as a lead-free Ball projectile with the same L/D ratio.

However, it's a safe bet that if 6.5mm CT ammo were to be adopted, at some point in the future an armor-piercing load would be developed and fielded, just as has been done with current and previous rifle/machine gun ammo.

Or why the tracer would be a consideration at this point. We'll shape the tracer to best fit the best possible combat bullet.

That could be a short-sighted and costly error. For example, M855 Ball only needs a 1:9 rifling twist, but M856 Tracer needs 1:7 twist. If all 5.56mm weapons had been fitted with 1:9 twist barrels to stabilize the Ball round, it would've been necessary to do a very expensive retrofit to be able to use Tracer ammo. It's called, PLAN AHEAD.

Speaking of which has the 5.56 tracer been modified since the M193 was developed?

Yes, most certainly. M196 Tracer was adopted for use with M193 Ball, and replaced by M856 Tracer with adoption of M855 Ball.

Below, l. to r.: M193 Ball; M196 Tracer; M855 Ball; M856 Tracer; Mk262

[LRRPF52]

The M855A1 projectile configuration already has barrier defeating properties with an exposed steel penetrator, which doesn't cause any problems for the LSAT since there is no feed ramp and pressures with the CT ammo are different, with a more efficient burn for more speed.

The 855A1 can also be configured with different bases and heads for the AP and tracer, since 855A1 has a copper jacket, a copper slug base, and a steel penetrator head. They also have a 7.62 LSAT with a larger case, but it is still smaller and much lighter than linked 7.62 NATO.

[Variable]

Excellent point. I never thought about the polymer case negating the ramped jump to the chamber.

Maybe a case scaled roughly halfway between the 5.56 and 7.62 cases with a steel tipped 6.5 projo?

[LRRPF52]

Barrels don't heat up as fast with LSAT either, since the chamber is separate, and the rotating chamber doesn't heat up as fast because the polymer absorbs a lot of the combustion heat. Since there is no neck or shoulder, the new cartridge pushes the spent case out of the chamber while feeding, so feeding and extraction happen simultaneously.

There is no need for a mechanical extractor with lip, extractor spring, or extractor pin, because the new cartridge is the extractor. It's a genius design really, eliminating some of the most problematic parts of conventional metallic cartridge operating systems. You start to see why it crushes the SAW in MTBF rates.

[stanc]

The 855A1 can also be configured with different bases and heads for the AP and tracer, since 855A1 has a copper jacket, a copper slug base, and a steel penetrator head.

Hmm. Has this has actually been done, or are you just speculating? I ask because neither seems feasible to me.

The M855A1 penetrator has a relatively complex shape, whereas current AP rounds have tungsten carbide penetrators that are simple, pointed cylinders (due to the difficulty in machining that material).



As for a tracer bullet with the M855A1 penetrator, wouldn't the pressure from the burning propellant expel both penetrator and trace element out the front of the bullet jacket?

They also have a 7.62 LSAT with a larger case, but it is still smaller and much lighter than linked 7.62 NATO.

Yeah, it significantly shorter, but slightly fatter, than the 7.62 NATO round. There's a superb photo in post #184.

[stanc]

Maybe a case scaled roughly halfway between the 5.56 and 7.62 cases with a steel tipped 6.5 projo?

Case diameter might be about halfway between those of the 5.56 and 7.62 cases, but I'd expect case length to be greater than that of the 7.62 case. That's if a heavy, high-BC bullet is used, as some here postulate. Such a 6.5mm projectile would be noticeably longer than the 7.62 M80 bullet.

[stanc]

More on the 7.62 LSAT LMG:

http://kitup.military.com/2015/05/textron-unveils-ultra-light-7.html#more-29809

http://www.thefirearmblog.com/blog/2015/05/21/textrons-lsat-program-unveils-7-62mm-plastic-cased-machine-gun-mockup/?utm_source=rss&utm_medium=rss&utm_campaign=rss

[motoxxx_ryder]

Hmm. Has this has actually been done, or are you just speculating? I ask because neither seems feasible to me.

The M855A1 penetrator has a relatively complex shape, whereas current AP rounds have tungsten carbide penetrators that are simple, pointed cylinders (due to the difficulty in machining that material).



As for a tracer bullet with the M855A1 penetrator, wouldn't the pressure from the burning propellant expel both penetrator and trace element out the front of the bullet jacket?



Yeah, it significantly shorter, but slightly fatter, than the 7.62 NATO round. There's a superb photo in post #184.

the tracers usually have a small cap on the back so it doesn't ignite in the barrel, if im not mistaken they typically dont ignite for 2-300 yards.


have you guys seen the LWMMG, they used the 338 norma catridge in a belt fed can of whoop ***! prob not what you want to lug aorund but it sure does look fun.

https://www.youtube.com/watch?v=Klr0EXZty6s

[cory]

There's a thread here where that MMG was discussed. It's about the same weight as the 240G. We got a pretty deep into a discussion on employing that MMG and a 6.5 Grendel LMG, taking the place of the SAW, 240G, and 50cal. It'd be an incredible combination.

Now with the LSAT, it seems it could be a real possibility.

[stanc]

the tracers usually have a small cap on the back so it doesn't ignite in the barrel, if im not mistaken they typically dont ignite for 2-300 yards.

Yes, modern tracers are typically designed for delayed ignition, although burn starts at much less than 200 yards. However, that has nothing to do with my question.

have you guys seen the LWMMG, they used the 338 norma catridge in a belt fed can of whoop ***! prob not what you want to lug aorund but it sure does look fun.

Of course it's fun. It's a machine gun!