How could or should the 6.5 mm Grendel be improved?

[stanc]

Despite the budget problems, there has probably never been a better time to argue the case for a change in calibre.

I agree. The question is, which of the candidate cartridges being developed will be the best option?

[LRRPF52]

Do you think anyone posting on or reading these forums can change the way the men are trained? I would say most know they should be better trained, IMO it's kind of a waste typing it. Murray may have the right idea about building a better lmg and neither the 6.8 or Grendel will fill that role. A lighter high performance cartridge that will work in the LMG and DM rifle could be a plus, at least the DM can shoot it...or should be able to shoot it.

The more people who are made aware of it, the better. At least with the LMG and DMC, even retarded units can benefit from a change. In the meantime, somebody needs to start asking what is going on with TRADOC, IET/AIT, IOBC, WLC, ALC, ANCOC, AOC, and the SGM Academy, because they are failing miserably.

[BluntForceTrauma]

It's both interesting and good to understand the larger issues facing our military, because our drive for a better service cartridge is based on the same desire to see increased overall effectiveness. However, asking those who are interested in small arms to go outside of their bailiwick is a little like expecting the plumbers to fix the framing of a house. We all have our own small role to play in the grand scheme of things.

John

[LRRPF52]

It's both interesting and good to understand the larger issues facing our military, because our drive for a better service cartridge is based on the same desire to see increased overall effectiveness. However, asking those who are interested in small arms to go outside of their bailiwick is a little like expecting the plumbers to fix the framing of a house. We all have our own small role to play in the grand scheme of things.

John

Excellent point. Not much the plumbers can do if the roof is caving in, but has a nice coat of paint on it and a detail of young soldiers propping it up so the structure looks like it's intact for the civilians footing the bill.

[cory]

...I would say most know they should be better trained, IMO it's kind of a waste typing it. Murray may have the right idea about building a better lmg and neither the 6.8 or Grendel will fill that role...

Why is that?

[stanc]

Why is that?

Because 6.8 SPC lacks sufficient range, and 6.5 Grendel lacks enough power?

[cory]

Because 6.8 SPC lacks sufficient range, and 6.5 Grendel lacks enough power?

I agree with the initial, but could you define sufficient power please?

[stanc]

I agree with the initial, but could you define sufficient power please?

GPC proponents consider 6.5 Grendel muzzle velocity to be 100-200 fps too slow to replace 7.62 NATO.

[cory]

And 6.8 proponents consider the Grendel to be too small and slow. It doesn't mean there's any merit to the claims.

What exactly is the minimum velocity for an LMG and where is that number derived from?
Does it not make more sense to define the requirement of an LMG as penetrating Z barrier at X distance?

[woohoo]

And 6.8 proponents consider the Grendel to be too small and slow. It doesn't mean there's any merit to the claims.

What exactly is the minimum velocity for an LMG and where is that number derived from?
Does it not make more sense to define the requirement of an LMG as penetrating Z barrier at X distance?

All you have to do is submit your rifle and ammo system to the military for testing and show them it is what they need...prove to them it will do the job. Reliability, ballistics, terminal performance on soft targets and barrier defeating performance.
Would you drop several hundred thousand dollars into proving a system and then not get a contract?
They are using 308s now, If it was me and my money I would not think about a system that did not BEAT the 308s performance and do it with a lighter and smaller package.

ETA- Look at the SCAR. That was in development for years through a crap load of changes. They adopted it for use in some areas then 6mths later dropped it. The Grendel has been around since what 2002? the 6.8 since 2004. The military isn't exactly jumping all over either one. If there was a magic cartridge it seems some military somewhere would show some interest.
One other thing - As civilians we like to compare off the shelf bullets but, the military will likely not use off the shelf bullets. It seems they are going all green and will design projectiles to fit the purpose. Any diameter or caliber can have the same BC if the same formula in relation to calibers is used.
The only difference is the weight of the projectiles. Being green they are lighter than lead core, a change from.264-.277 using the same formula only increases the bullet weight apx 5-6gr.

[stanc]

And 6.8 proponents consider the Grendel to be too small and slow. It doesn't mean there's any merit to the claims.

What 6.8 SPC proponents think about 6.5 Grendel doesn't matter. The point that woohoo made is that neither of those two cartridges offers sufficient performance to replace 7.62 NATO for infantry machine guns.

Even LRRPF52 thinks that 6.5 Grendel would need to be modified for this purpose by greatly increasing chamber pressure, and thereby boosting muzzle velocity.

What exactly is the minimum velocity for an LMG and where is that number derived from?

AFAIK, there is no such figure specified anywhere.

Does it not make more sense to define the requirement of an LMG as penetrating Z barrier at X distance?

Yes, I agree that objective requirements for performance are a must, and comparison to 7.62 NATO performance seems the logical approach.

- Would 6.5 Grendel provide the same or better terminal effects at all ranges as 7.62x51, using the same type bullets?

- Would 6.5 Grendel with Ball ammo (not Scenar match bullets) deliver the same or better trajectory and wind drift as 7.62x51 Ball?

- Would 6.5 Grendel with Ball ammo (not Scenar match bullets) deliver the same or better grazing fire capability as 7.62x51 Ball?

- Would 6.5 Grendel Tracer rounds be visible to the same distance as 7.62x51 Tracer?

These are valid concerns.

[cory]

All you have to do is submit your rifle and ammo system to the military for testing and show them it is what they need...prove to them it will do the job. Reliability, ballistics, terminal performance on soft targets and barrier defeating performance...

Exactly! To make the assumption that the Grendel is an inadequate LMG round is misguided to say the least.

[cory]

...The point that woohoo made is that neither of those two cartridges offers sufficient performance to replace 7.62 NATO for infantry machine guns.

Even LRRPF52 thinks that 6.5 Grendel would need to be modified for this purpose by greatly increasing chamber pressure, and thereby boosting muzzle velocity.

Here's our issue, y'all want to replace the Platoon and Mounted LMGs the 240 Gulf. If that's the case I tend to agree with LRRPF52, but why are we concerning ourselves with that here. That LMG and dismounted Infantry weapons using the same round makes no sense, at least to me.

I thought we were talking about replacing the squad level LMG the SAW. The Grendel seems perfect for that LMG.

Yes, I agree that objective requirements for performance are a must, and comparison to 7.62 NATO performance seems the logical approach.
I agree, but what you're and most of these threads have been discussing is a meet or exceed comparison. I disagree there. Now if you want to do a meet or exceeds comparison with the best rounds expected from our enemies to the Grendel and the NATO 7.62. Then use that data to determine if the Grendel surpasses the enemy's capability to a magnitude comparable to the NATO 7.62. There I think is a resonable discussion.

- Would 6.5 Grendel provide the same or better terminal effects at all ranges as 7.62x51, using the same type bullets?
No, no bullet smaller than the 7.62X51 will do this, while saving weight and reducing recoil.

- Would 6.5 Grendel with Ball ammo (not Scenar match bullets) deliver the same or better trajectory and wind drift as 7.62x51 Ball?
Maybe, worth looking into.

- Would 6.5 Grendel with Ball ammo (not Scenar match bullets) deliver the same or better grazing fire capability as 7.62x51 Ball?
Define grazing fire capability please. If you're asking can it effectively impact dirt at the same distance. Very likely.

- Would 6.5 Grendel Tracer rounds be visible to the same distance as 7.62x51 Tracer?
Unless we're trying to replace the 240 Gulf I think this is a mute point.

These are valid concerns.

We're just not going to be able to have our cake and eat it too. There's no magical bullet that'll do all the things the 7.62 can while reducing weight and recoil. At least not with current smokeless powder technology. There has to be trade offs.

[woohoo]

Exactly! To make the assumption that the Grendel is an inadequate LMG round is misguided to say the least.

Easy to say when you're not investing your money to prove it to the military.
Why are cases tapered? Is there a belt or links that work with the Grendel? A LMG that will shoot the Grendel? The 120fmj MAY BE light enough to meet the weight reduction requirements but can the Grendel push that to the velocity needed to beat the 308 out to 800yds out of short barrels?
Someone would need to show all of that and more could be done. If you walked up and handed the right guy in the mil a Grendel cartridge the military is not going to say "hey great idea we'll jump right on this" or they would have already. After A'stan many think our LMGs need to have the range that the 7.62x54 does or better in order to engage the enemy at the range they are engaging us.
It can be done but not with cases that have a net capacity of 28gr.
In my first post I answered the question "How could or should the 6.5 mm Grendel be improved?" If I was going to pitch the Grendel that is what I would do.
LE don't need a long range round. A carbine in the military to replace the M4 may be a possibility, it will hit the same obstacles the 6.8 did. $ and they don't know what they want. All of the talk in the whole thread is speculation, all of it. Speculation could drive invention.

[SHORT-N-SASSY]

Exactly! To make the assumption that the Grendel is an inadequate LMG round is misguided to say the least.

And, let's investigate its true performance from an "enhanced" version, in a beefed-up platform such as the Remington R-15 .30 RAR, free from the limitations imposed upon it in the standard AR-15 platform, due to its larger rim size.

[stanc]

Here's our issue, y'all want to replace the Platoon and Mounted LMGs the 240 Gulf. If that's the case I tend to agree with LRRPF52, but why are we concerning ourselves with that here.

I thought we were talking about replacing the squad level LMG the SAW. The Grendel seems perfect for that LMG.

The main issue is the weight of 7.62 machine guns and ammo used by dismounted infantry. What is desired is a LMG that fires lighter ammo, but has the same effectiveness as a 7.62 GPMG. Such a LMG could replace the 7.62 M240B/G, 7.62 Mk48, and 5.56 M249.

Define grazing fire capability please.

I don't recall the exact definition, but it has to do with the range for which the maximum trajectory height does not go above a certain amount, so the bullets won't pass harmlessly over the heads of advancing enemy troops. The flatter the trajectory, the longer the grazing range.

[stanc]

Exactly! To make the assumption that the Grendel is an inadequate LMG round is misguided to say the least.

It is not an assumption. It's a conclusion based on analysis of available info. From the OP:

Against this backdrop the armies of several NATO members are looking at alternate calibers. Not surprisingly the 6.5 mm Grendel is starting to receive a lot of attention. it is certainly a highly respected solution and is now being evaluated widely. With all due respect to forum members own testing, a consensus opinion about the Grendel appears to be forming from within the military community. Let me underline the issues:

•The Grendel doesn't quite match 7.62 mm at 1,000 metres across all combat scenarios

[woohoo]

And, let's investigate its true performance from an "enhanced" version, in a beefed-up platform such as the Remington R-15 .30 RAR, free from the limitations imposed upon it in the standard AR-15 platform, due to its larger rim size.

Pull out quickload and run a calc. using a 16" barrel. Take a bullet the size of a 139 Lapua, weight it at 112gr, give it a G7 BC of .25 and extend the OAL of the cartridge to where the only part of the bullet that is in the case is the boat tail and .264 body....384 total. Now , that will require a longer mag than a AR15, maybe 2.5" Compare that to the 7.62x54.
In order to get a .25BC the length must be closer to 1.39". 58,000psi -16" barrel resulted in a velocity of 2480fps.
The 7.62x54 loads run 26-2700fps using fairly high BC bullets weighing as much as 175gr. The AP load will defeat 1/4" armor plate at 722yds.
From the testing we ran in 08 if the steel core bullet is lighter it must travel faster to penetrate the same steel plate.