Taking Back The Infantry Half-km: Britain’s L129A1

[Float Pilot]

it was made to fight our enemies. It was not made just to fight the NVA. If that was all it was made for we would have switched back to the M14 or made something else already.

The AR-10 (mid 1950s) was designed as an all- around rifle. The 22 caliber, high velocity stuff as a secondary project was worked on by a couple other folks besides Stoner... However the initial few years field use first by the Air Force and then the Army was in South East Asia. Remember that it was non-infantry guys like Lemay (AF) and that goof ball Sec Def McaNamara who pushed it through. The Regular Army was not crazy about it..
How it worked or did not work there (S.E.A.) , led to changes in ammo, twist rate, fire doctrine and all sorts of other ideas on war-fighting.
Had conditions been different during that 10 year period, the M16 and 5.56mm may have well been superseded or modified before they sank more money into it...

One of the first things they taught us in command school was that the USA has the tendency to prepare, train and supply with the last war in mind.

The bullet is not overstabilized in 1:7 twist unless you use too light of a round. Then, the spin literally tears it apart. But for 55-~80 grains, 1:7 is ideal.

No it is not ideal for the 62grain bullet. They went to the 1 in 7 twist so it would stabilize the much longer tracer round that was developed for the SAW. It is bullet length, not weight, which determines the needed twist rate. Even 45 grain bullets of modern construction hold together just fine in the 1 in 7 twist.

Your number-one choice is basically destroying what range the M4 has by now possibly understabilizing the bullet.

My comment was for urban fighting, building interiors etc. The stuff that sub-guns and shotguns were really made to do...

A 1 in 9 twist stabilizes 62 grain M-855 just fine. Even at reduced velocity from a 11.5 inch barrel. We tested it at 400 meters and there was no impact yawing.
In fact it allows slightly more velocity to be produced since it reduces friction. The twist rate would have to be played with to strike a balance. For urban fighting at ranges out to 300 meters , a marginally stabilized bullet will tumble (often) when entering a body. A fast spinning round , at the reduced velocities caused by the 14.5 inch barrel, tends to poke a hole more often than not.
Of course an impact velocity of 2,500 to 2,600 is preferred for any sort of massive trauma from a small bullet. The short M4 hampers that considerably.

 

[Bartholomew Roberts]

For urban fighting at ranges out to 300 meters , a marginally stabilized bullet will tumble (often) when entering a body. A fast spinning round , at the reduced velocities caused by the 14.5 inch barrel, tends to poke a hole more often than not.

Your statement seems to contradict this one:
http://ammo.ar15.com/ammo/project/term_twistduh.html

They make a pretty good case that the difference in gyroscopic stability between a 1:14 and 1:7 is negligble on whether the bullet tumbles or not (as all spitzer based bullets will eventually in a mostly liquid medium), so how can the difference between a 1:9 and a 1:7 be of any significance?

 

[Bartholomew Roberts]

The real problem with the AR-platform (M4 Carbine) is that the M4's in Afghanistan have 14.5 inch barrels. You really begin to castrate the 5.56x45 round when you do that. There simply isn't enough time for the powder to burn and give the projectile enough energy to travel at speeds necessary for it to be effective against a human target at 300+ meters.

Assuming an initial muzzle velocity of 2,900fps for the M4, M855 at 400yds is travelling 1,833fps and has 463 ft/lbs of energy. Going on a muzzle velocity of 3,110fps for the M16A2, M855 at 400yds would be travelling 1,998fps and have 550 ft/lbs of energy.

Both rounds are travelling slower than even the minimal speed required for M855 to fragment after yaw, so in what kind of scenarios will that extra 100lbs of energy make a difference in effectiveness and what kind of difference will it make?

Quote:
Originally Posted by Bartholomew Roberts
How often are you going to be able to observe a definite, clean hit on a combatant at 300m+ and then also note the round was ineffective?

When the guy you were shooting at keeps shooting.

When is the last time you shot a target at 300m and were able to observe that your .223 hit it? Is the guy shooting at you because .223 is ineffective or because you never hit him to begin with? Maybe the guy is only 200m away and you have been zipping rounds over his head because ranging with the Mk1 Mod 0 eyeball is tricky work?

 

[Float Pilot]

Your statement seems to contradict this one:

Yes I did , and still do... he contradicts himself in this answer....
http://ammo.ar15.com/ammo/project/term_m855yaw.html

My personal observed experience is based upon over 30+ years of active and reserve military deployments along with my 20 years of police work. When you are forced to attended autopsies, you get to see all sorts of interesting internal damage. Being an avid experimental hand-loader and hunter also adds to a knowledge of bullet wounds in real flesh... not jello.
When an 18 year old is busy talking to the intel weanies, with a chest wound that looks like he was stuck with a knitting needle, you tend to question your equipment.

I chronographed 62 grain M-855 ammo from a regular issue M16A2 20 inch bbl (1 in 7) and a M-4 14.5 inch barrel (1 in 7 twist)

I had 3,080 fps for the average from three A2 rifles and 2,812 fps as the average for three M-4s.

Just for chuckles, I also fired 20 rounds of old M-193 ball ammo from the A2s. The average was 3,140 fps. Something else came up before I could run some through the M4s.

If you figure that 2,600 to 2,700 seems to be the magic number for M-855 to fragment, an M4 does it at 50 meters while a 20 inch A2 does it at 150 meters.

Back when the A2s were a new thing, some of us Guard and Reserve folks (had real jobs) still had A1s. During deployments we would occasionally get the new green tip M-855 ammo by mistake. While you could not make a chest shot past 50 meters with the stuff in an A1, it did do interesting things to fleshy targets within 25-35 meters.
One Airborne LRS-Det I was in kept A1s until 1993 since they were lighter and had the full auto capability... talk about a logistics problem..

When is the last time you shot a target at 300m and were able to observe that your .223 hit it? Is the guy shooting at you because .223 is ineffective or because you never hit him to begin with? Maybe the guy is only 200m away and you have been zipping rounds over his head because ranging with the Mk1 Mod 0 eyeball is tricky work?

Range calculation (SWAG) is often way off, I have seen 35 troops all shooting at one target and only one solid hit occurred at 400 meters. Plus another light wound that looked like a jacket fragment. Even troops who shoot expert throw rounds all over the place under stress. That is also why during police shootings the Officer involved often thinks he fired one or two shots when he / she really emptied their firearm. (Often holstering empty due to bad training taking over)

 

[Hammerhead6814]

Assuming an initial muzzle velocity of 2,900fps for the M4, M855 at 400yds is travelling 1,833fps and has 463 ft/lbs of energy. Going on a muzzle velocity of 3,110fps for the M16A2, M855 at 400yds would be travelling 1,998fps and have 550 ft/lbs of energy.

Care to backup any of that with a link? This is what I got. When it comes to the 55 gr especially you start to see a difference.

 

[Bartholomew Roberts]

Yes I did , and still do... he contradicts himself in this answer....
http://ammo.ar15.com/ammo/project/term_m855yaw.html

Where do you see a contradiction in that link? He mentions that M855 has different yaw characteristics from lot to lot, due to reduced velocity and fleet yaw. My understanding is that you feel that yaw in flesh is somehow changed by the twist rate - which wasn't mentioned anywhere in that link.

While you could not make a chest shot past 50 meters with the stuff in an A1, it did do interesting things to fleshy targets within 25-35 meters.

Earlier, you seemed to be asserting that a twist rate that stabilizes a bullet in air is also enough to stabilize it in flesh. So I don't see how a twist rate that doesn't stabilize a bullet in air is really relevant to that topic - or did I misunderstand you?

Care to backup any of that with a link? This is what I got.

Your link has basically the same muzzle velocity numbers as mine. What is it you are wanting me to back up? The 400yds figure for muzzle velocity and muzzle energy is from the Ballistics ballistic calculator using the preprogrammed M855 data.

When it comes to the 55 gr especially you start to see a difference.

Yes, 55gr is going to have even less energy and velocity at 400yds. because it has a worse ballistics coefficient.

 

[kenno]

I was NEVER a fan of 5.56 ESPECIALY in 1970, but in 1970 I had m-60s, hand grenades and Claymores and 60mm motars and 81mm motars and even 120mm mortars. I am here to tell you a 120mm Mortar can kick some serious ass. Behind all that was most of the US Military.
What was the question again?

 

[Maverick223]

The real problem with the AR-platform (M4 Carbine) is that the M4's in Afghanistan have 14.5 inch barrels. You really begin to castrate the 5.56x45 round when you do that. There simply isn't enough time for the powder to burn and give the projectile enough energy to travel at speeds necessary for it to be effective against a human target at 300+ meters.

Either switch back to the 20 inch barrels in Afghanistan, use a bullpup (barrel length 20 inches), or start sending every squad out with 2-3 designated marksmen with an AR-10 each.

My thoughts exactly. The sooner we embrace the bullpup configuration and develop one that sufficiently suits our needs, the better. There is a reason that many developed nations seeking a new weapons platforms have turned to the bullpup configuration...it solves more problems than it creates and works well in varying environments/conditions/types of warfare.

 

[Carter]

My thoughts exactly. The sooner we embrace the bullpup configuration and develop one that sufficiently suits our needs, the better. There is a reason that many developed nations seeking a new weapons platforms have turned to the bullpup configuration...it solves more problems than it creates and works well in varying environments/conditions/types of warfare.

Well there are a few problems with introducing bullpup's:
-Left handed shooters can't use them (unless using a FN2000 type system..or even a p90 system)
-bad trigger pull (never shot one but thats what EVERYONE seems to say)
-I would imagine it'd slow the mag change a bit (but thats what training is for)
-The military has been too cheap to replace the m4 for how many decades...I doubt they'd put up the money for brand new bullpups that they don't even like, nor would they try to have one designed and built.

However, I love bullpups. I think they are the future of rifles. But it will be a long time before they are seen as standard issue in the hands of American forces.

 

[Maverick223]

Well there are a few problems with introducing bullpup's:
-Left handed shooters can't use them (unless using a FN2000 type system..or even a p90 system)
-bad trigger pull (never shot one but thats what EVERYONE seems to say)
-I would imagine it'd slow the mag change a bit (but thats what training is for)
-The military has been too cheap to replace the m4 for how many decades...I doubt they'd put up the money for brand new bullpups that they don't even like, nor would they try to have one designed and built.

1.Some bullpups (henceforth referred to simply as "BP") are ambidextrous. A new design would likely be necessary.
2.Some BPs have outstanding triggers (my Desert Tactical SRS being the best I have used) and the RFB is supposed to be good as well (utilizing a similar design), but that isn't really necessary in a standard issue weapon. Even my M17 has a pretty decent trigger (I can easily and effectively engage head sized targets at 300M+), more than good-nuff' for an issue rifle. The BP conversion kits tend to have horrible triggers, a good BP needs to be designed from the ground up IME.
3.That is a real concern, but I can load mine about as fast as an AK (I am proficient with both), so I find it to be acceptable.
4.You can't fix cheap. Use the M16 for now (for longer engagements), and plan to replace all M4s and M16s with a BP platform at some point.

 

[C-grunt]

The real problem with the AR-platform (M4 Carbine) is that the M4's in Afghanistan have 14.5 inch barrels. You really begin to castrate the 5.56x45 round when you do that. There simply isn't enough time for the powder to burn and give the projectile enough energy to travel at speeds necessary for it to be effective against a human target at 300+ meters.

Either switch back to the 20 inch barrels in Afghanistan, use a bullpup (barrel length 20 inches), or start sending every squad out with 2-3 designated marksmen with an AR-10 each.

There already are several people on a standard squad who hve weapons that have effective ranges of over 500 meters. 2 SAWs, a M240 and a DMR. Plus the M203s for things a little bit closer. So for a 10 man squad, minus the squad leader, thats 4 out of 9 that have long range weapons.

Id also bet a good bit of money that the marksmanship at 300+ meters is way more of a problem than the 5.56 lack of lethality at that range. Trying to hit a guy at 300 meteres who is running around in the mountains using cover, using concealment and other general actions to not get shot, is no easy task.

 

[Al Thompson]

other general actions to not get shot, is no easy task

Rubbish! <sarcasm> Hundreds if not thousands of internet posters can easily hit a standing man at 800m with a .22LR or my name's not Walter Mitty!




On a more serious note, I've lost track of the number of folks I've taken to our local range who's jaws dropped upon seeing a "real" 200m rifle range. 300m or yards is a long ways off in the real world.

 

[Maelstrom]

Or we could always stick with the AR platform and switch between 5.56 and 6.8 uppers as needed.

If the military is looking for simplicity then you've got it there. The AR is modular, USE IT!

 

[HorseSoldier]

The real problem with the AR-platform (M4 Carbine) is that the M4's in Afghanistan have 14.5 inch barrels. You really begin to castrate the 5.56x45 round when you do that. There simply isn't enough time for the powder to burn and give the projectile enough energy to travel at speeds necessary for it to be effective against a human target at 300+ meters.

Nope. The 99% of the real problem is putting steel on target at 300+ meters against some guy who's doing his damnedest to not get zapped. Until you solve the target acquisition and engagement part of the puzzle for individual issue weapons whinging and whining about barrel length and what distance 5.56mm fragments at and if switching back to 7.62x51 or 45-70 or 0.60 caliber Kentucky rifles or whatever else is amateur navel gazing at its worst.

In the modern era that "amateurs talk tactics, professionals talk logistics" truism should be modified to "amateurs talk caliber and barrel length, professionals talk training."

 

[JShirley]

If you have one. My take is that most of these engagements are foot patrols taking shots from the heights around them. By the time air or anything heavier comes up, the shooters are gone.

Kodiac, see the numerous statements in this thread mentioning that US squads and teams carry crew-served weapons with them. Also, in most environments in Afghanistan, vehicles are continually close by.

At least once while I was in Afghanistan at a remote outpost, some of the ODA claimed we had been shot at, but I did not see or hear these shots*. Meaning they were nowhere close to us.
Even when it was obvious we were taking fire from rockets, the closest hits I saw were only close enough to blow open a door and toss a little dirt onto our walls.


*Of course, this was coming from 7th Group, most of whom I didn't respect all that much. 3rd Group was another story.