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Grendel as a Universal Infantry Cartridge - JASmith - 12-02-2013
The 130 grain interest comes from the notion that retained energy is an important parameter for projectile effectiveness. It is not.
The closest the total energy at impact comes to having a significant effect is the sound and size of splash heard and seen by troops near it. This is, at best, a weak argument mostly because any splash or noise will get their attention if they know that serious or lethal injury will result if they get hit.
We know that bullets of weighing 60 grains or more are highly effective on live targets.
The remaining issue is total penetration through timbers and hard targets. Here the useful metrics are the momentum and momentum densities which are the sectional densities multiplied by the velocity or square of the velocity.
The 6.5 does very well, especially at long ranges. compared to the 7.62 Russian and 7.62 NATO when these metrics are employed.
Hence, we can go with a green bullet weighing 95-100 gr for an infantry carbine and 110-120 gr for the LMG.
We might not need to invoke a longer COL for the LMG -- just accept pressures of 55,000 to 60,000 psi to get excellent long range performance. This would maintain emergency ammunition interoperability to cover those exceedingly rate events when one type or another is not available.
Grendel as a Universal Infantry Cartridge - Michael - 12-02-2013
JASmith Wrote:The remaining issue is total penetration through timbers and hard targets. Here the useful metrics are the momentum and momentum densities which are the sectional densities multiplied by the velocity or square of the velocity.
If anyone is interested in bullet penetration, here is a link to a video on a test done a few years ago
http://www.liveleak.com/view?i=29d_1318009976
My experience in the 3d world is 5.56 punches through shanty town buildings with no issues (think Somalia), and .50 BMG/HMG has a hard time getting through some of the think mud walls (Afghanistan/Iraq). This goes back to the premise posed by LRRPF52 as to where we will fight...and I agree wholeheartedly with his assessment. Asymmetric urban environment in the littoral regions.
Grendel as a Universal Infantry Cartridge - Tony Williams - 12-02-2013
SHORT-N-SASSY Wrote:Tony Williams,
Thank you for your clarification.
1, Using identical projectile style, how much longer would a 130-grain .264" diameter projectile be vs a 130-grain .277" diameter projectile?
2, To maintain the same length of a 130-grain .277" projectile, what weight would the .264" diameter projectile have to be?
I don't know - I was just looking at illustrations of actual bullets, I don't have a bullet design program.
Grendel as a Universal Infantry Cartridge - woohoo - 12-02-2013
Tony Williams Wrote:Not necessarily: the Barnes 6.5mm 126.5 grain LRX bullet is solid copper with a hollowpoint filled with a polymer tip. It measures c.35mm long (the same as a lead-cored 6.5mm 140 grain Berger VLD) which gives a length/diam ratio of around 5.2. The problem comes when you want a tracer version of the bulletÂ….Tony,
Incidentally, the LRX has a G7 BC of .460, a G1 of .230 while the Berger's numbers are .612 and .313 respectively - the cost of going lead-free! OTOH the LRX will have a higher MV due to the reduced weight, even though the propellant space will be about the same.
Why don't you get all of the test data in a poly version together and present it at the NDIA meeting. That would be a start at getting everyone to consider it for CLAWS.
Grendel as a Universal Infantry Cartridge - Tony Williams - 12-03-2013
I'm probably not going to the next NDIA - it clashes with something else I want to do.
Grendel as a Universal Infantry Cartridge - BluntForceTrauma - 12-03-2013
If you've got a .308, PCP Ammunition is looking for testers of their polymer-cased .308.
John
Grendel as a Universal Infantry Cartridge - LRRPF52 - 12-03-2013
Here's the link for the civilian testing: http://www.pcpammo.com/limited
Grendel as a Universal Infantry Cartridge - Trooper - 01-17-2014
At least someone is developing a polymer case. It makes no sense to leave brass on the battlefield. Polymer is lower cost and lighter weight. Even against aluminum or steel cases.
Grendel as a Universal Infantry Cartridge - Trooper - 01-17-2014
One thing. With comparison to the .308, the 6.5x55 Swede is the standard. Thus the .260 Rem or the 6.5mm Creedmoor come close. The 6.5x47 Laupa comes up a bit short. The standard is to move a 6.5mm round weighting 140 gn. at 2550 fps out of the barrel. That would be equivalent to the .308 with a 192 gn. bullet. http://www.eabco.com/6.5_mm_cartridges.html
Thus it would be difficult to make a round that would fit into a standard M4 magazine well that would be able to compare to the 6.5x55. Especially using a 140 gn. bullet. Thus we would be using a smaller round but might be able to do about 80% of what the .308 does. With a lot less recoil.
If we need a heavier round for a medium MG, the .338 NM (8.6x63) would do. the .338 has a similar BC (.600) to what the 6.5mm has.
Grendel as a Universal Infantry Cartridge - LRRPF52 - 01-17-2014
Trooper Wrote:At least someone is developing a polymer case. It makes no sense to leave brass on the battlefield. Polymer is lower cost and lighter weight. Even against aluminum or steel cases.
Did you see the other thread about PCP ammo? Their semi-polymer cases are a total failure.
Grendel as a Universal Infantry Cartridge - Trooper - 01-18-2014
Well, I can only hope. It is such a waste to leave brass on the battlefield. Steel would work as would aluminum.
BTW, I could not find the other thread. Is it in this forum or the one on ammo?
Grendel as a Universal Infantry Cartridge - cory - 01-18-2014
Trooper Wrote:Well, I can only hope. It is such a waste to leave brass on the battlefield. Steel would work as would aluminum.
BTW, I could not find the other thread. Is it in this forum or the one on ammo?
I believe the thread referenced a link to a review at 8541 Tactical. You should be able to find it there.
Grendel as a Universal Infantry Cartridge - Tony Williams - 01-18-2014
Trooper Wrote:One thing. With comparison to the .308, the 6.5x55 Swede is the standard.
Why?
The 6.5 x 55 with a modern 140 grain bullet would greatly outperform 7.62mm at long range, but there would be no saving in size or weight and not a lot in recoil. The Army would never go for that - not enough advantages. A c.6.5mm round which matches the 7.62 x 51 M80's long-range performance while achieving significant savings in weight and recoil would be a lot more attractive (and even that won't be an easy sell).
Grendel as a Universal Infantry Cartridge - Trooper - 01-18-2014
Tony Williams Wrote:Why?
The 6.5 x 55 with a modern 140 grain bullet would greatly outperform 7.62mm at long range, but there would be no saving in size or weight and not a lot in recoil. The Army would never go for that - not enough advantages. A c.6.5mm round which matches the 7.62 x 51 M80's long-range performance while achieving significant savings in weight and recoil would be a lot more attractive (and even that won't be an easy sell).
I am going by Arthur Browns comments as he is one of the big proponents of the 6.5mm in the US. http://www.eabco.com/6.5_mm_cartridges.html
In their opinion, the 6.5mm is the perfect round. But it does not gain in advantage if pushed more than 2700 fps. In their comparison, using the 6.5x55 Swede as the standard to measure against, it goal was to match a bullet weighting 140 gn going 2500 to 2700 fps out of the barrel. With those features, the 6.5mm easily matches the .308 with a 192 gn bullet out to at least 700 meters. Rounds that meet that standard are the .260 Rem, the 6.5mm BRM (based on the .30-30 cartridge), the 6.5mm Creedmoor, and maybe the 6.5x47 Laupa. With a 140 gn bullet the Grendel comes out of the barrel at 2000 fps, giving about 80% of the .308 energy at 700 meters.
The point is that if we would want to match the .308 then it is going to take a much larger casing. But if we are willing to do most, but not all, of what the .308 (7.62x51) does then the 6.5 Grendel is a good candidate for the GPC.
For long range shooting at magnum velocities, the .338 family of rounds (8.6x63NM, 8.6x70LM) give similar BC of .600 (like the 6.5mm) with less barrel wear.
Maybe it is time to move to the 6.5mm for GPC for the common infantry rifle and designated marksman with one lite MG (SAW). But move to the 8.6mm (NM?) for long range sniping and the medium MG (M240).
Grendel as a Universal Infantry Cartridge - JASmith - 01-18-2014
I think we all agree that the 6.5 caliber is an excellent hunting caliber.
The caliber has good potential for creating a weapon system superior to those based on the 7.62 caliber when light materiel and personnel are the targets. The Grendel can be shown to be superior in many of the roles, particularly the LMG.
The challenge revolves around the resistance to changes in caliber when major breakthroughs in firearms technology are "just around the corner." BTW, these breakthroughs have been imminent since the late 1950's making the 60+ year run somewhat a record for a major new technology.
Hence, Tony & his debate community have been searching for and working to invent a caliber / case combination that might have enough superiority to compel a change in basic firearms cartridge in one or more major military forces. The Grendel case is, to date, the closest to satisfying the goal.
The order is a tall one and a noble goal. I have participated in the discussions, and will continue to do so off and on as time permits.
Grendel as a Universal Infantry Cartridge - cory - 01-18-2014
Trooper Wrote:...With a 140 gn bullet the Grendel comes out of the barrel at 2000 fps, giving about 80% of the .308 energy at 700 meters...
That MV is incorrect. I can safely get 2400 fps out of my 24" that seems to be on the slower side of other 24" barrels. 2225fps+ out of a 16" is a safe beat in my opinion. I'll be confirming that velocity this spring with my 16" Lilja barrel that should be en route soon.
Will a longer max COL due to magazines, those MVs can be significantly improved.
Trooper Wrote:...For long range shooting at magnum velocities, the .338 family of rounds (8.6x63NM, 8.6x70LM) give similar BC of .600 (like the 6.5mm) with less barrel wear.
Maybe it is time to move to the 6.5mm for GPC for the common infantry rifle and designated marksman with one lite MG (SAW). But move to the 8.6mm (NM?) for long range sniping and the medium MG (M240).
I agree!
Grendel as a Universal Infantry Cartridge - stanc - 01-19-2014
JASmith Wrote:[6.5mm] has good potential for creating a weapon system superior to those based on the 7.62 caliber when light materiel and personnel are the targets. The Grendel can be shown to be superior in many of the roles, particularly the LMG.Perhaps. I'm still waiting to see test data that confirms it.
Quote:Hence, Tony & his debate community have been searching for and working to invent a caliber / case combination that might have enough superiority to compel a change in basic firearms cartridge in one or more major military forces. The Grendel case is, to date, the closest to satisfying the goal.6.5 Grendel is the closest production round, but there are some experimental 6.5mm cartridges that reportedly are superior. These are essentially "stretched" versions of 6.5 Grendel. One such is a 6.5x45 being developed by Harrison.
Grendel as a Universal Infantry Cartridge - Trooper - 01-19-2014
stanc Wrote:Perhaps. I'm still waiting to see test data that confirms it.
6.5 Grendel is the closest production round, but there are some experimental 6.5mm cartridges that reportedly are superior. These are essentially "stretched" versions of 6.5 Grendel. One such is a 6.5x45 being developed by Harrison.
The Grendel was designed to be 6.5x39. Was that to pattern after the 7.62x39? Does the 6.5x45 work as well in M4/M16 mags?
Grendel as a Universal Infantry Cartridge - stanc - 01-19-2014
Trooper Wrote:The Grendel was designed to be 6.5x39. Was that to pattern after the 7.62x39?AFAIK, 6.5 Grendel is an evolution of the 6.5 PPC, which was derived from the .220 Russian, which is a necked-down 7.62x39.
Quote:Does the 6.5x45 work as well in M4/M16 mags?Not even. Due to OAL of circa 2.6 inches, the 6.5x45 cartridges require a longer magazine, and therefore a bigger rifle like the DPMS GII or FN SCAR-H.
Grendel as a Universal Infantry Cartridge - Trooper - 01-20-2014
stanc Wrote:AFAIK, 6.5 Grendel is an evolution of the 6.5 PPC, which was derived from the .220 Russian, which is a necked-down 7.62x39.
Not even. Due to OAL of circa 2.6 inches, the 6.5x45 cartridges require a longer magazine, and therefore a bigger rifle like the DPMS GII or FN SCAR-H.
How much more energy is developed by the 6.5x45 than the 6.5x39?