Military round comparisons

[Tony Williams]

-- AFAIK, the US JAG rulings on hollowpoints like the SMK and SOST rounds authorize their use against not only criminals and terrorists, but also lawful combatants (i.e., members of national armed forces). Other countries JAG equivalents have ruled such projectiles are illegal. They can't both be right.

You surely don't expect lawyers to agree on such issues, do you? They make their living from disagreeing with other lawyers, after all....

By and large, the US takes a more robust approach to arguing with the ICRC over this issue than most European lawyers are willing to. The Europeans (including the UK) tend to be super-cautious. For instance, the standard British 5.56mm ball round has long been the L2A2. The L2A1 was dropped when it was realised that the thin jacket allowed ready fragmentation, so the L2A2 has a thicker jacket.

[LRRPF52]

The Finns won't use the Lapua Scenar either in sniper rifles, but use a lock-base FMJBT instead.

[bwaites]

- Not all of the people we're fighting are terrorists. Some are patriots waging guerilla warfare against foreign invaders.

Who would that be, the Taliban is outlawed in Afghanistan? So far as I know, we aren't fighting anyone else.

- AFAIK, the US JAG rulings on hollowpoints like the SMK and SOST rounds authorize their use against not only criminals and terrorists, but also lawful combatants (i.e., members of national armed forces). Other countries JAG equivalents have ruled such projectiles are illegal. They can't both be right.

Which lawful combatants have they been used against? I'm not debating the possibility, just don't think we have faced any lawful combatants of late.

Hmmmm....

[stanc]

Hmmmm....

Bill, you make it impossible for me to quote you when you insert your responses in material you're quoting. :p

My understanding is that we are fighting at least five different opponents:

- al-Qaeda
- the Taliban
- jihadists from other Islamic countries
- criminals (i.e., drug smugglers, etc)
- ordinary Afghans who object to foreign troops in their land (Note that the insurgency began after large numbers of Western soldiers occupied Afghan towns)

SMK rounds may have been used against the Iraqi Army in 1991 and/or 2003. But, whether they were or weren't, the point is that they are authorized for use against regular armies, not just against terrorists.

[stanc]

You surely don't expect lawyers to agree on such issues, do you? They make their living from disagreeing with other lawyers, after all...

First, we're not talking about trial lawyers arguing a case before judge and jury. Second, my point is that either the US JAG is right, or the UK and other countries are right, but one side necessarily must be wrong.

[JASmith]

Do we not know that justice and the law are largely shades of grey subject to vast ranges of interpretation?

[LRRPF52]

Needs new thread. Various insurgencies have been sponsored by Pakistan and Iran in competition for Afghanistan's precious terrain for decades, even during Soviet occupation. You have drug warlords, Shia surrogates for Iran, Sunni surrogates for Pakistan, Turkic tribes in the north, smugglers, mercenaries, and every which way but Sunday flavor of jihadis running about in Afghanistan.

[stanc]

Needs new thread.

Or, we could just get this train back on track.

It doesn't really matter if expanding and fragmenting bullets are illegal or not. Nobody cares enough to make an issue of it, and the US has demonstrated that it will do whatever it pleases, anyway.

[cory]

the us has demonstrated that it will do whatever it pleases, anyway.

ooh rah!

[Guardsman26]

I think it is right to say that the USA is fully prepared to follow the course of action it believes is right. Hence the M855A1. Theoretically, this improved ammo is a great idea. In reality, it is expensive to produce, has mired the army in litigation with the original patent holder of the design, requires weapons to be re-zeroed versus ordinary M855 ammo - a huge risk factor if ammo types are mixed on the battlefield, has very high chamber pressures (almost at proof testing limits) and still doesn't provide significant overmatch versus Russian 7.62 mm x 54R.

A GPC projectile made from steel and copper could be highly effective. We're seeing impressive new designs emerge that provide much better barrier penetration en route to a target and much better soft tissue performance. What Nammo did with the Norwegian Army's 5.56 mm ammunition shows what can be done while achieving green credentials.

And, of course, while the list of enemies is valid, it is by no means complete.

[woohoo]

(Tony Williams - who else?)

Absolutely right, Stan. Thank you for pointing that out. And the SF community is seriously interested in a weapon in a calibre that can deliver the associated benefits.

The Canadian paper study presented at Shrivenham last year showed just how effective the Grendel could be - when fired from a weapon with a 24" barrel. It has done much to re-ignite the calibre debate in military circles.

However, as soon as you fire the existing 6.5 Grendel from a weapon with a 16" barrel, retained energy levels drop-off alarmingly - to the point where the Grendel offers no appreciable difference versus 5.56 mm. This has been tested and validated by at least two mainstream manufacturers. (It may also explain why Dr. Gary Roberts gel tests were inconclusive). Hence my view that a slightly longer cartridge with increased powder capacity would easily overcome the problem and provide a true GPC round.

One of the other things I've been looking at is whether an extended version of the 6.8 mm Remington SPC case would be a better alternative to an extended Grendel case. While it would create a longer, more slender round, as LRRPF52 points out, the Grendel case can take more pressure. So, the 39 mm 11.3 mm case is the right one to extend IMO.

I like everything about the Grendel round except case length. A long case with a less pronounced shoulder would also facilitate easier feeding.

Murray's 7mm UIAC is more or less a Grendel extended. The Carcano is close too. He designed a bolt a little larger than my 800 series AR15 bolt but smaller than an AR10 bolt. I machined them for him last year. The problem I see with the 7mm bullets is the BC is low until the heavier weights are used then because of the weight they are slow with the case capacity what it is. One thing, the Grendel/Lapua cases will not handle more pressure than a 6.8 SSA/Hornady case...The Remington cases are junk. The larger diameter of the Grendel case extended will have more case capacity than the SPC case if the same caliber projectiles are used.
A .441 diameter case, 46mm long, 2.5" OAL of cartridge will have apx the same case capacity as my 270AR (based on the 6.5x47 shortened) 130gr Berger (BC of .496) hits close to 2800 from an 18" barrel in the AR15 platform. That velocity with a 123gr 6.5 or a 130gr .277 with respective BC will smoke a 308 even using Lapua 155s.
ETA- that velocity is close to 58,000psi, still 2700fps out of an 18" barrel is plenty to outperform a 308.

[LRRPF52]

Roger that on 7mm being too heavy for weight/BC advantage.

One thing, the Grendel/Lapua cases will not handle more pressure than a 6.8 SSA/Hornady case...

I was talking with Lapua's R&D team, and they have run the Grendel case 15% higher than .300 Win Mag pressures in a Sako bolt gun. Brass is ruined, but never failed. The more I deal with it, the more I like the fact that the Grendel runs at a lower pressure than 5.56 or 7.62, because it really doesn't need it.

As I run my DM Courses and compare my 16" Grendel against 77gr Mk.262 from 18" guns, there are very clear differences in performance between the two as far as wind-drift and retained energy goes. A sub-1/2 MOA capable 5.56 has less chance of a hit at distance than my ~1 MOA Grendel. You know when you hit a steel plate with the 123gr from the Grendel out to 600yds. Even with 77gr 5.56 at 2820fps mv, it's very difficult to register hits past 400yds, especially with a tailwind. The BC of the 77gr SMK leaves a lot to be desired.



Any case with a .473" head diameter takes it out of the Assault Rifle Intermediate Cartridge Category from a soldier's load & mag capacity perspective (unless we rewind the clock to the pre-1950 era with the .276 Pedersen & 7.92x33 Kurz), but does introduce interesting possibilities for the hunter and competitor, who will be mostly using magazines of no more than 5 or 10rd capacity.

I saw your mention of .270AR on your site. Are you setting the shoulder back as well, or just trimming the neck? Any pics of a loaded cartridge?

ETA: Just found most of my answer:

I took a 6.5x47 case and pushed the shoulder back .120 then necked it up to .277. It has a little more case capacity than a BRX and using the 6.5x47 case no fire-forming is needed.
Early testing shows out of an 18" barrel, using CFE223 powder 120gr bullets will hit 2850, 130gr Bergers 2700fps . 8208 pushed the 130 Bergers to 2788fps at the max load of 36gr.
The exterior ballistics of that 130 load beat the 308 M118 load and it runs right with the 308 shooting 155gr Lapuas so even though it was intended as a larger AR15 hunting cartridge it should hold it's own at long range target too.

[Trooper]

First, we're not talking about trial lawyers arguing a case before judge and jury. Second, my point is that either the US JAG is right, or the UK and other countries are right, but one side necessarily must be wrong.

Any good attorney will tell you that, at best, all he can give you is an opinion (a very learned opinion). Only a judge can give a ruling that has the force of law. And it takes an appellate level court (panel of judges) to give a ruling stature.

[Trooper]

(Tony Williams - who else?)

Absolutely right, Stan. Thank you for pointing that out. And the SF community is seriously interested in a weapon in a calibre that can deliver the associated benefits.

The Canadian paper study presented at Shrivenham last year showed just how effective the Grendel could be - when fired from a weapon with a 24" barrel. It has done much to re-ignite the calibre debate in military circles.

However, as soon as you fire the existing 6.5 Grendel from a weapon with a 16" barrel, retained energy levels drop-off alarmingly - to the point where the Grendel offers no appreciable difference versus 5.56 mm. This has been tested and validated by at least two mainstream manufacturers. (It may also explain why Dr. Gary Roberts gel tests were inconclusive). Hence my view that a slightly longer cartridge with increased powder capacity would easily overcome the problem and provide a true GPC round.

One of the other things I've been looking at is whether an extended version of the 6.8 mm Remington SPC case would be a better alternative to an extended Grendel case. While it would create a longer, more slender round, as LRRPF52 points out, the Grendel case can take more pressure. So, the 39 mm 11.3 mm case is the right one to extend IMO.

I like everything about the Grendel round except case length. A long case with a less pronounced shoulder would also facilitate easier feeding.

When comparing to the 7.62x51 NATO, remember that it was designed for a 20" barrel (M14 or the FN FAL), not for a 16" as we have on the M4. Thus comparisons need to be with 20" barrel platforms. Thus how does the 7.62 NATO fired from a FAL or M14 compare to the 6.5mm Grendel fired from an M16 (AR15) having an 18" or 20" barrel? Even the M60 MG or the M240 MG use longer barrels.

The shorter M4 barrel would not be a good comparison. Even the 7.62 NATO does not perform well out of a 16.5" barrel. But then that is not why we use the shorter barrels. One should not expect good performance out of a shorter barrel. The shorter barrel is for close quarters work. If we want .308 performance then we use a 20" barrel for the 6.5mm Grendel.

[LRRPF52]

A 16" barrel pushing 175gr SMK's will beat a 20" barrel spitting 147's and 168's all day long. BC is king, which is why we talk about it so much. The days of the 20" battle and service rifles are almost over. Even modern bullpups are born with 16" barrels.

A 20" barrel does jack for you, because they are very difficult to shoot positions with in combat, unless you're an extremely large man. Add SOPMOD accessories to the mix, and the longer guns become stupid to try to shoot positions with. Even the 18" SPR is difficult to shoot positions with.

I'll take my 16" Grendel and have a higher hit probability at distance than my 22" .260 Rem. from positions other than prone supported, simply because you can't steady the 22" .260 that well. It doesn't matter how much energy you miss with, only that you missed.

This is why I'm liking the 16" Grendel more and more. Handles like a mouse gun, hits like a hammer, more mag capacity than 7.62 NATO at less weight, with 50% of the recoil of a 7.62 NATO. For a military gun, there is no reason to have a barrel longer than 16". The current trend is to go 16" barrel on all the 7.62 NATO rifles as well.

[Tony Williams]

Murray's 7mm UIAC is more or less a Grendel extended. The Carcano is close too. He designed a bolt a little larger than my 800 series AR15 bolt but smaller than an AR10 bolt. I machined them for him last year. The problem I see with the 7mm bullets is the BC is low until the heavier weights are used then because of the weight they are slow with the case capacity what it is.

Agreed, plus the other problem is that the weight of high-BC 7mm bullets means that the weight saving over 7.62mm M80 may be too small to be worth bothering with.

The Grendel provides the superior long-range performance needed to replace the 7.62mm combined with a very worthwhile weight saving, but only from a long barrel and firing high-BC lead-cored bullets. Combine the use of short carbine barrels with the current insistence on lead-free bullets (which will protrude more deeply into the case, reducing powder capacity - especially with tracer bullets), plus the potential for a polymer/metal hybrid version of the case (the coming thing) which reduces the case capacity by maybe 10%, and you get a performance shortfall which can only be made up by a bigger case. Something like the 7x46 UIAC necked-down to 6.5mm should do nicely.

And by the way, the performance from 20" barrels does matter, because that's likely to be the length of the tube of a GPMG firing any new intermediate round. At long range, a GPMG is surely more important than a carbine in terms of effective squad firepower.

[woohoo]

5.56, 6.8. 270AR. 6.5x47, Creedmoor, 308.
[ATTACH=CONFIG]3341[/ATTACH]
I agree with others including Murry that a true mid sized cartridge could do it all. 1 cartridge for CQB, sniping and work in a LMG. Murry's 7mmUIAC is a great case size but I think a 6.5 or .277 projectile would perform better as an all around cartridge. It's very close to the 6.5x47 but the diameter of the Grendel. At 2.5" OAL it would require a new platform or a AR10 sized lower allowing for the longer carrier travel and smoother recoil impulse.
I like others believe if a cartridge the diameter of the Grendel is used in a combat rifle the bolt head would need to be larger for reliability. Murry's bolt was designed for a LMG so it's larger than what would really be needed for a combat rifle.
Photo shows a typical AR15 bolt beside Murry's bolt. Material was a soft test alloy to test the tool path, that's why it looks gummy. Next photo is AR15 bolts and my 800 series bolts(.441 and .473) which are plenty strong enough to handle the BRXs I've been shooting and the smaller .441 diameter cartridges
In 2010 I built 28 "AR12s" for lack of a better term. They were built on DPMS LR lowers with a down sized upper to cut the weight. Changing AR10 barrel profiles to AR15 barrel profiles removes much weight then the carrier loses another 4oz. Most were 308s but a few were built in 6.5x47. 308 or full sized ammo is still heavier than it needs to be. New powder designs are better than the old so we really don't need a case the size of the 308 now, the 6.5x47 proved that. A 7lb combat rifle with a decent barrel profile(not lightweight) is possible. No one in combat likes excess weight. Developing a new platform including mags and brass would be very expensive for a small business.

Will the NATO countries change? I doubt it but it would be nice to see.

[woohoo]

Roger that on 7mm being too heavy for weight/BC advantage.



I was talking with Lapua's R&D team, and they have run the Grendel case 15% higher than .300 Win Mag pressures in a Sako bolt gun. Brass is ruined, but never failed. The more I deal with it, the more I like the fact that the Grendel runs at a lower pressure than 5.56 or 7.62, because it really doesn't need it.

:

I love Lapua cases. They are thin and allow more capacity in the same sized case. I don't think they will handle any more pressure than any other cases. In 30-35years of reloading and developing wildcats since 83 I've had 4 cases rupture. 1 was a 243 Winchester and the other 3 were Lapua, 2 of which were the 6mmAR. Does 10X behind a 95gr SMK in a Lapua case sound familiar? I've had a lot of BR and BRX cases turn out looking like a belted magnum. Haven't had as much swelling with their 243 and 308 cases. Still I love Lapua cases, can't be beat. For combat the pressure should be held down around 55k. Could be more on sniper/slow fire loads and less on CQB or full auto loads where it isn't needed.

[LRRPF52]

The Finnish Defense Forces Sako brass is top-notch as well, even if Berden-primed.

Service rifles/carbines shouldn't have a full auto feature, unless it's a 2-round burst that doesn't ruin the pull weight in the SEMI mode, like the 3rd burst mech does.

A 7mm is too much for CQB, unless you cut the pressures (and velocity) way down.

[SHORT-N-SASSY]

Re the February 5, 2013 Reply, by Tony Williams, shown below.

Tony, indeed! --- And, I mirrored your proposal in a letter I sent to Dr. Franco Gussalli-Beretta, Executive Vice President, Fabbrica D'Armi Pietro Beretta S.p.A., dated April 30, 2012:

"Dr. Gussalli-Beretta:

Upon the introduction of the highly-innovative Beretta ARX-160, at the 2011 SHOT Show --- and, later, welcome word that the Civilian Model would be available, 'months, not years,' ahead --- there was much anticipation among our shooting fraternity. A long-time bullpup enthusiast, I envisioned the ARX-160 as the basis for a state-of-the-art 21st Century bullpup rifle, particularly, with its forward-thinking ambi-ejection (reinstating Citizen-First-Class status to left-handed shooters) and super-quick-change barrel feature (hopefully, to include the highly-desirable 6.5mm Grendel chambering, for extended-range targets). Indeed, a review of comments on several websites, following the ARX-160's introduction, confirmed that this assessment was shared by others, as well. With great expectation (upon the expected availability of the Civilian Model), I had planned to remove the collapsible, folding buttstock (the resulting package satisfying the minimum legal overall length for a rifle) and fashion a forward fire-control unit (a bit of a challenge, to say the least).

Enter: the IWI Tavor TAR-21 bullpup rifle, Civilian Model, formally introduced at the 2012 SHOT show, with word that it will be available in the fall of 2012 --- along with the discouraging update that the Beretta ARX-160, Civilian Model, won't be available until sometime in 2013, at the earliest. The TAR-21 is a very capable, desirable bullpup rifle (one that I'm presently considering), though it still requires partial disassembly to change the breech bolt, for left-side ejection, and lacks a quick-change barrel feature. What to do.

In view of all the above, I submit that Beretta in this interim has an uncommon opportunity to dominate the fast-growing bullpup rifle market, by going the last yard with its planned Civilian ARX-160: drop the buttstock, add a buttplate, remove the rear portion of the Picatinny Rail and relocate the hand grip-trigger assembly, forward --- and, for those bullpup purists, among us, complement the ARX-160's list of innovative features, by incorporating a battery-powered electronically-actuated one-pull-one-shot trigger-sear assembly.

On behalf of bullpup enthusiasts, everywhere, your consideration is appreciated. Thank you."

NOTE: My proposal for including an electonically-actuated trigger-to-sear arrangement was for the Civilian Model, only.

[/FONT]

Of course, if a long barrel is needed to extract the performance you want without going to a bigger and more powerful cartridge, then there's an obvious answer...work on a decent* bullpup design, and enjoy a 20 inch barrel in a gun the same overall length as an AR-15 with a 10-12 inch barrel.

*fully ambidextrous without having to dismantle and rebuild the gun, and with an adjustable stock length.