Third Generation Battle Rifle

[stanc]

This puts me back on my broken record track of the need for a new LMG, which would really provide a noticeable set of capabilities for the Infantry Rifle Squad and Platoon, especially if it demonstrated an acceptable set of performance parameters that could deal with the PKM for reach and penetration, with significantly less weight and recoil for the gunner.

This puts me back on my broken record of wishing someone would actually demonstrate it.

[bwaites]

This puts me back on my broken record of wishing someone would actually demonstrate it.

Stan!!! Welcome back!

[Variable]

Stan!!! Welcome back!

Ditto! Welcome back.

As for demonstrating performance---

People keep telling me that M855A1 (the copper core trial winner, not the other one) is the new hotness, but I haven't managed to get any in my mitts.

I wonder what the grain weight would be for a similar 6.5 projectile which received M855A1 style treatment? Maybe 110 grains? If you replaced the rear copper slug with steel (cost reduction) and kept the front steel penetrator seperate (so it'd still snap on yaw), how much powder space would be lost? Maybe not that much?

http://usarmorment.com/pdf/M855A1.pdf

I'm thinking that penetration with 6.5 sectional densities would be pretty darn good, and the new M855A1 is purported to be decently accurate to boot.

[ricsmall]

5.56 rounds 2.jpg5.56 rounds 2.jpgnot to derail, but that is very impressive variable! I have some unknown to me 5.56 rounds that have a brown colored, plastic? tip. You can just about remove the tip with your fingernail. Can anyone enlighten me as to what kind of round it is? Im thinking a frangible round, but dont know for sure. Ill try and get a pic up in a bit.

i looked closer, part of the tip i took off and under it looks like copper. Any ideas?5.56 rounds.jpg

[Variable]

I can't tell in those pics (distorted view), but maybe they are 5.56 "Optimized" rounds? Basically similar to a Barnes Tipped triple shock IIRC

[SHORT-N-SASSY]

My limited research has failed to produce the Ballistic Coefficient of the 62-grain steel-core projectile used in the M855A1 EPR. Can anyone help?

[Variable]

My limited research has failed to produce the Ballistic Coefficient of the 62-grain steel-core projectile used in the M855A1 EPR. Can anyone help?

I can't find it either, except for this: http://www.chacha.com/question/what-...-m855a1-bullet

"A 62 gr M855A1 bullet has a Ballistic Coefficient: 0.371. Initial Velocity: 2970 fps."

Needless to say, an anonymous unattributed answer on "Cha-Cha" isn't anything I'd cite anywhere.LOL

[LRRPF52]

The word I'm hearing about M855A1 is that it buckles people in half, even from 10" carbines.

[Michael]

Variable - here is your bullet with more info. http://www.aschq.army.mil/ac/aais/ioc/LCAAP/Industry_Day/634272332137343750.pdf

[stanc]

Ditto! Welcome back.

Thanks, guys. Wish I could say I'm having fun...

As for demonstrating performance---

People keep telling me that M855A1 (the copper core trial winner, not the other one) is the new hotness, but I haven't managed to get any in my mitts.

I wonder what the grain weight would be for a similar 6.5 projectile which received M855A1 style treatment? Maybe 110 grains?

Maybe. My guess would be circa 100 grains.

If you replaced the rear copper slug with steel (cost reduction) and kept the front steel penetrator seperate (so it'd still snap on yaw), how much powder space would be lost? Maybe not that much?

I dunno. Need somebody more knowledgeable to answer that.

I'm thinking that penetration with 6.5 sectional densities would be pretty darn good...

Concur.

[Trooper]

This puts me back on my broken record of wishing someone would actually demonstrate it.

The PKM is firing the 7.62x54R which is equivalent to the .30-06 or the British .303 so we are dealing with a medium MG. The PKM then is more like our M240. How do those two compare in performance? How equivalent is the .308 to the .30-06 or .303 British?

Would it be possible to convert the M249 to 6.5 Grendel for testing?

[Trooper]

If we ever do go to an GEN III battle rifle, there are only a few companies able to compete. FNH, Beretta, Remington/Bushmaster are the top three. Next tier would be HK, Colt, and IWI. After that I am not sure who could deal with the production and design costs.

Are any of these companies even designing for the 6.5 Grendel? Almost all of them do have a GEN III rifle.

[SHORT-N-SASSY]

I can't find it either, except for this: http://www.chacha.com/question/what-...-m855a1-bullet

"A 62 gr M855A1 bullet has a Ballistic Coefficient: 0.371. Initial Velocity: 2970 fps."

Needless to say, an anonymous unattributed answer on "Cha-Cha" isn't anything I'd cite anywhere.LOL

Among the results from a subsequent search for more detailed information on the new, improved M855A1:

1, M855A1 - ShootersCalculator.com --- "Bullet Weight, 62 grains; Ballistic Coefficient, 0.371; Initial Velocity, 2970 fps."

2, M855A1: Should it be the New Round for Soldiers and Marines? Guns & Ammo, March 7, 2012 --- ". . . It shoots flatter. Of course the reason it shoots flatter is because they've juiced the round up so that it will fly at 3,100 fps. This would be a great achievement except for the fact that they did it by increasing the chamber pressure from 55,000 psi to 63,000 psi. That's a number closely approaching proof-load pressures. . . ."

3, An Army Outgunned - Physics Demands A New Basic Combat Weapon, By Joseph P. Avery, Ph.D, Military Review July-August 2012 --- "America's National Security strategy demands that our combat forces defeat enemy combatants across the full spectrum of battlefield environments, not just leafy jungles or the plains of Europe. Despite an increasing portfolio of enemies that are flexible, well armed, and robust, our Army, Marine Corps, and special operations forces have been stuck for decades hauling assault rifles firing NATO 5.56x45 millimeter (mm) (.223 caliber) varmint rounds over a half-century old. A decade into a new century, we need to adopt a more robust projectile and basic combat weapon (BCW) to meet current and emerging performance requirements. . . . In another attempt to address the significant shortfalls of our current BCW, the Army recently developed the lead-free, M855A1, 5.56mm, 62 gr. Enhanced Performance Round, tipped with a steel arrow penetrator and more powerful propellant *. . . . Ballistic Performance - The physics of external ballistics and current and future combat environments appear to demand a new caliber of weapons --- whether or not based on the M16 chassis. Many firearm experts, combat users, and studies have recommended the heavier and modernized 123 gr., 6.5x39mm Grendel Lapua Scenar cartridge as a replacement for the current 5.56mm NATO and possibly the 7.62mm NATO as well. . . . There is also a possibility that a 6.5mm cartridge, which fits into the 5.56mm magazine, could be 'enhanced' with a steel penetrator and more powerful propellant. That would provide the 123 gr. package with theoretically double the devastation and longer range than the M855A1 Enhanced Performance Round, giving our forces the edge in any combat environment and at any range. . . . A Versatile and Reliable BCW - United States combat forces require a versatile and reliable BCW with the ability to incapacitate the enemy at close quarters, with sufficient ballistic energy to smack-down enemy forces with authoritative force at long distance. We can either analyze the newly developed and currently existing 6.5mm cartridges, or attempt an expensive development of a new family of ammunition. Assessing the recently developed 123 gr. Lapua Scenar 6.5mm, with its high velocity, flat trajectories, and greater knockdown power than the 5.56mm well beyond 600 meters, may be a place to start. The new family of 6.5mm projectiles has over twice the lethality of the 5.56m, M855 NATO round, and regardless of the configuration, with a 123 gr. projectile that does not go subsonic until 1,275 yards, if you can see a target, you can theoretically hit it **. . . . Additional testing is required, and there is always the option of designing an entirely new platform around the current or an enhanced 6.5mm cartridge. It may be prudent to release a group of 6.5mm, M16-chassis weapons for operational field testing in Afghanistan by deployed forces to test against the 5.56mm M855, M855A1 Enhanced Performance Round, and AK47. Research should look into possible enhancement of an even more powerful 6.5mm Enhanced Performance Round, but the enhanced round may not be ideal under all combat conditions. . . ."

All of which prompted me to revisit Bolt Thrust FAQ (http://www.beyond556.com/bboard/show...olt-Thrust-FAQ).

* Wikipedia --- M855A1, "The new SMP-842 propellant in the round burns quicker in the shorter M4 carbine barrel, ensuring less muzzle flash and greater muzzle velocity."
** To wit: LRRPF52's recent eye-opening weekend excursion to 1,200 yards, with his trusty 16" 6.5 Grendel and Hornady's 123-grain A-MAX load, aired in these pages.

[Gamecock84]

Good eval. I agree with most everything that is said, but worthy (usually=costly) optics are not trashed by the SCAR-H. I can speak to that personally.

Both the SCAR-L and SCAR-H trash optics and SOPMOD accessories due to increased g-loadings on the return stroke of the action. I suspect it's because the SCAR does not have a sectional reciprocating mass like the AR15 family does, where the bolt carrier, buffer, and buffer weights are separate parts. The SCAR has no buffer system. It's basically an AR-18 operating system, which Armalite settled on in the 1960's because they had already licensed the Direct Impingement system to Colt, and could no longer legally make weapons with DI...but they wanted to.

The SCAR deals with recoil impulse and reciprocating mass with an elongated longitudinal cam pin travel in the carrier, which is great for dwell time and longevity of the bolt. The problem is that you have a BCG/oprod that weighs what a complete M4 carbine operating system weighs, impacting all at once when it chambers a new round. This has been identified as a source of major problems for things like optics, night vision, laser aiming modules, etc.

Within fragmentation range, the 5.56 can be brutal to be hit with, on an outside vital zone shot at that. Heck, people shot in the arms and legs with 5.56 within 200yds look horrible. I've seen it several times, and I only saw massive tissue damage, even on deflected rounds off body armor and rocks (fratricide incidents). It canoes people's heads open viciously, blows muscle tissue apart, fractures bones without even hitting them...basically all the hype isn't hype within 200yds.

It does get blown around by the wind-even the 77gr with a wimpy .362 BC sucks for energy and wind at distance. That's where 7.62 NATO comes in handy. It retains energy and cuts through the wind better. It is not ideal for kicking in doors or most of your close quarters engagement distances, unless everyone is wearing electronic muff ear pro and preferably using cans. 7.62 discharged indoors or even in blown-out buildings will rock your world, even when you're behind the guys who are blasting.

What I've heard about M855A1 is that is buckles guys in half, even from 10.5" Mk.18 CQBR M4A1's. I never used it as it came after I got out, but the sources who have related its performance to me are reliable.

In the end, I would opt for a deployable unit that had undergone a focused marksmanship training package that included shooting in wind conditions at distance more than an equipment solution. It wouldn't matter what caliber they had either, even though some are better than others. If your riflemen have no experience shooting in wind or at distance with formal instruction, they will just be missing anyway.

[montana]

The word I'm hearing about M855A1 is that it buckles people in half, even from 10" carbines.

I'm also hearing it shortens barrel life by over half ,the accuracy sucks, it's over pressured, and is very expensive.