Improved 308 combat loading?

[Ian]

Suppose you are going to war with a .308 semiauto rifle, and you get to specify what ammo you will use. What would you pick as general-purpose cartridge?

More specifically, I've gotten to wondering if there's good reason for the 150+ grain bullets being the predominant loads. It appears that back around the turn of the century, heavy (173gr) bullets were chosen for the '06 to maximize range when used in heavy machine guns. The 150 grain was a compromise for the M1 a few decades later, and the 308 was just made to duplicate the existing 150gr '06 load. I can understand the heavier, higher-BC 168s and 175s for snipers, but is there any really good reason for 150s as a general-purpose round? What about using 125s or 130s? Seems to me that would reduce felt recoil (and make for faster follow-up shots), while retaining plenty of barrier penetration capability. It would also extend the battle sight zero, for what that's worth.

So, why not a 125gr at 3000fps instead of a 150gr at 2800fps?

 

[Deer Hunter]

I'd like to see us use some thin-jacketed 110 grain FMJ loads for the .308. Maybe stick a semi-steel core in them to give them 5.56mm AP like performance.

 

[Jim Watson]

Your chronology is a little off.
The .30-06 was introduced with a 150 gr spitzer as an improvement over the .30-03 220 gr roundnose inherited from the Krag. It was only during WW I that long range machine gun barrages became of value and interest and the M1 173 gr boattail was standardized after the war. The M1 Garand was designed to shoot that ammunition when Mr G changed it from .276 Pedersen. In the 1930s the 173 was problematical for shooting about half again as far as 150s and exceeding many range limits. So they ran off a supply of ammo with 150 gr bullets for safe shooting and by WW II it was standardized because arty, air, and the .50 had taken over the role of long range support.
Actually, as WW II progressed, there was more and more use of armor piercing as the usual load anyhow.

There is little call for innovation in .308/7.62 these days, and where it is still used, in machine guns and sniper or marksman's rifles, a lighter bullet would be no advantage.

 

[Nightcrawler]

My personal "SHTF" or whatever load is 150 grain jacketed soft points. Good mix between penetration and expansion I think, and they're often loaded a bit hotter than old 147 ball.

 

[gunnie]

150gr ball ammo

all the options promoted above do have their merits...

but consider what we know the 150gr ball load to be capable of:

stopping power- the germans were amazed at how much more lethal the 150gr/30 cal was than the ammo they issued in WWII. the cause for this is that it typically starts tumbling after about 6" in hemo-gooh.

penetration- uncle sugar rates the 150gr 7.62x51 ball loading
for pentration of 4+ FEET of pine @ 200 meters (53"). 2 cinder blocks @ 200 meters. they also say it takes 1/2" hardened steel armor plate to repeatedly stop the ball loading. these stats are the army's findings for BALL, not AP.

no, it won't stop soft targets as well as an HP or SP. BUT, when one shoots at others in the most dangerous species, they usually take cover rather than running into the woods as animals will.

when the SHTF, perhaps there are other considerations as well as dramatic stops on soft tissue?

gunnie

PS- the truth is sometimes stranger than ted kennedy...

most states will not allow hunting game with ball ammo. the geneva convention REQUIRES ball ammo for shooting human beings?

 

[Shooter973]

308 loadings?

If I remeber correctly the 308 was developed around the 147-150 gr bullet weight. Optinum velocity and carry were the prime consideration. Heavier bullets just added weight for the troops. The powder capacity of the case just doesn't throw the heavier bullets as well. (180's ) or even the 200's.
I do ALL of my 308 loading around the 147-150 gr bullets and have had very good perfomance from them in every case. I do keep a few 163 gr AP's loaded but don't shoot many of them, just enough to know the diffrerances in POI, from my 150gr. loads.

 

[Lucky]

it takes 1/2" hardened steel armor plate to repeatedly stop the ball loading

That doesn't sound quite right. I had some graphs a while ago, I'll see if I can dig them up, dealing with penetration and distance of FMJ and AP rifle-caliber bullets.

Oh well, there's still the info on this page: http://www.inetres.com/gp/military/infantry/rifle/762mm_ammo.html


AP will penetrate 0.28" (7mm) at 300m, where ball will penetrate 4mm.

No idea what testing criteria there, but even if that's V50 (penetrates half the time) and 60degrees, it's still less than half inch at 90degrees.

the geneva convention

Hague, two versions out there; The

-1899 "Contracting Parties agree to abstain from the use of bullets which expand or flatten easily in the human body, such as bullets with a hard envelope which does not entirely cover the core, or is pierced with incisions."
-1907 (US signed) "it is especially forbidden:…To employ arms, projectiles, or material calculated to cause unnecessary suffering"

Note that 5.56 has a fragile cannelure that is similar to the notion of incisions, and 5.45 is designed to bend (but perhaps not 'flatten'). And even though there should be no problems using HP against fighters in Iraq the US JAG barely squeaked out a decision allowing MatchKings to be used, because their jacket is formed from the base and makes type of HP, though in the most generic way only.


But the general idea made sense for an age where professional armies were forming, a clear distinction was made between civilized warfare and combating colonial savages, and it was becoming impractical to have hordes of crippled veterans living as beggars while trying to recruit good men to make the military their profession.

 

[PercyShelley]

But the general idea made sense for an age where professional armies were forming, a clear distinction was made between civilized warfare and combating colonial savages, and it was becoming impractical to have hordes of crippled veterans living as beggars while trying to recruit good men to make the military their profession.

Throughout the history of war, there has been a tendency to pull punches a bit. Battles in the classical era tended to have fewer than 20% casualties, and tribal warfare is full of examples of ritualized combat that had the net effect of reducing casualties.

It's why we don't use nukes and chemical weapons on each other; like Clausewitz said, war is politics by other means. What good is a military victory if all the other relevant parties think you're scum because of how you fought?

That, I suppose, is an interesting sociological discussion for another time, however.

The .308 is a frustrating cartridge. On the one hand, it's good. On the other hand, it's not a 30-06.

A 30-06 can comfortably shoot 200 grain projectiles at 2500 f/s while a .308 is hard pressed to keep those bullets above 2100. That's starting to look mighty slow.

That said, I like to use 165 grain bullets out of a .308 as an elk load, and have no complaints about trajectory.

That said, I've always had the option of switching to .300 mag for long range territory.

 

[cheygriz]

If I were going to use a .308 in battle, in a rifle, not a machinegun, I would like a specialy designed 150 grain bullet, soft point, rapid opening, with about a .20 caliber hardened steel penetrator insert. Since you can't carry much ammo in a caliber that large, ya gotta make 'em count!

However, if given a choice, I will stick to a standard, 20 inch barrel, 1-12 inch twist M-16 and standard M193 55 grain ball. The mortar crew, the SMAW team, the artillery, the helos and especially the Air Force can handle anything my M-16 doesn't take out.

 

[DMK]

Hornady 168gr. TAP

 

[bratch]

Wow. The 110 basically desinigrated(sp?)

 

[Zak Smith]

308 FMJ will not penetrate 3/8" AR500 armor steel at 50 yards. Don't remember shooting it closer, but we have shot XM193 from 20" barrels at 30 yards and it does not penetrate. Velocity is what kills armor steel.

I have shot 210gr Berger VLD bullets at 2300fps from a 24" bolt rifle. It was not a max load.

 

[PercyShelley]

The 155 grain shot got my attention; it doesn't sound like a bad load at all.

As for the 110, ouch. Just ouch.

 

[DMK]

The 155 grain shot got my attention;

I agree. It appears to tumble almost immediately and still has decent penetration. That's the round I keep loaded in my FAL mags and a few Ebloc clips for my .308 Garand. The 168gr. has slightly better penetration though and retains more mass while still leaving an impressive wound channel.

The 110gr. looks like it has the terminal performance of a varmint round. Explosive fragmentation, but looses all it's structural integrity so it doesn't penetrate deep.

 

[gunnie]

sem-six-tu

"That doesn't sound quite right. I had some graphs a while ago, I'll see if I can dig them up, dealing with penetration and distance of FMJ and AP rifle-caliber bullets."

LUCKY- the key word here is to ~repeatedly~ stop the ball load.

the same caveot could be made for ZAK's:

"308 FMJ will not penetrate 3/8" AR500 armor steel at 50 yards."

i'm no metalurgist, but "A"brasion "R"esistant plate IS very hard stuff. (AR prefix, followed by 3 digit brinell hardness #'s, higher # is harder) same is brittle as glass, and to be reliably welded, all kinds of pre/post heat hoops have to be jumped through. coupled with VERY high tensile strength filler metals, also tending to be brittle stuff.

see: http://www.aasteel.com/abrasion.html for more info on this.

caterpillar lines buckets and haul truck beds with hardox 400 equivalent steels. same is about as hard as is practical to use while retaining any kind of weldability and/or impact resistance.

armor plate can exhibit hardness #'s in the same range, see:

http://www.alleghenytechnologies.com/ludlum/pages/products/xq/asp/G.17/qx/ProductLine.html

but typically has greater tensile strength, and lower yield strength #'s. thus, it has to be able to flex/deform without breaking. this is where the "impact resistance" comes from.

the M-1 tank gets around this problem with layered metals. kinda like steel plywood, layers of hard metals with soft material sandwiched in between to cushion the impact of sectional breakage from outer layers.

the trusty old M-113 APC even uses 5356 aluminum armor plate. while it doesn't have the hardness #'s as a "T-6" alloy can, same is more welding friendly, but is treated for an exterior (case) hardness.

the point of all of the above drivel, is that armor plate has to exhibit high hardness #'s, while remaining maleable. this IS a slick trick, and a tribute to the genious of modern metals.

gunnie

bright lights,
thick smoke,
and a fool with a welder...

 

[Zak Smith]

It won't even touch the surface of the 3/8" AR500 armor plate at 100 yards. I can try this next time I have a chance, but based on our experience shooting 3100+fps FMJ from 5.56's, I would bet it's not going to penetrate or even cause cratering at 25 yards. At that distance, a 5.56 will only put an approx 1mm pock mark in the surface-- nothing like you see with mild steel (ie, deep/wide cratering in 1/2"+ thick plates).

To penetrate the AR500 plate with 5.56, you need to hit the exact same spot multiple times and eventually a plug will extrude through.

 

[HorseSoldier]

The only thing with 130 grain and less 7.62x51 loads that I see is that while they address some downsides of the load for a combat gun (faster handling from lighter recoil, etc.) you are then dealing with something a lot like a hot AK load in a case that's a half-inch longer than 7.62x39 and somewhat heavier, etc. Probably not the most efficient way to skin a cat.

If your combat scenario does not place a premium on large carried ammo load (i.e. SWAT entries for instance) it may not be a big deal, and the ability to switch to hotter/heavier loads 150 grain and higher provides some flexibility, but those 20 round 7.62x51 mags are still big and bulky compared to 7.62x39 or 5.56 alternatives.

 

[cpileri]

For informational purposes ONLY

Pls correct me if I am in error; but I believe the private individual can own and fire AP ammo in a rifle (not handgun). OK, the part I am not sure of is if a private citizen can MAKE rifle AP ammo for personal use (only). If he can...

Make sure steps 1 and 2 are done before beginning the assembly process, and that all supplies are at hand before beginning at all. Wear Personal Protective Equipment, etc. etc. Use at your own risk.

1. Make the penetrator
Lets say you want an approximation of the M855 steel penetrator core. The only ref I could find on the hardness scale for the penetrator core of M855 ammo indicated Rockwell C 54.
Take a steel nail, cut/hacksaw&file/dremel&file, etc to length desired, either short enough to fit inside the jacket fully or else long enough to have the rear end of the penetrator stick out from the base of the finished projectile and serve as a boattail. Let's go with shorter for now.
Sharpen it, perhaps by putting it in a drill chuck and spinning it while applying a grinding edge or something similar.
Then harden it.
Regular old low-carbon steel nails (not stainless) need about 1200-to-1700 degrees Farenheit. OK the truth is it depends on the carbon content of the steel, common everyday nails are anywhere from 0.1% -to- 0.4%, depending on which wire steel they are made from: . If another THRer with more expertise posts better info, then I defer to him/her. Remember, this is backyard, DIY, hardening I am thinking of.
For carbon steel, you want RED hot to get the hardness we’re after, which is at least Rockwell C 54.

Get yourself a Micro-Therm or MJ-950 Ultra-Therm Flameless heat gun which puts out hot air at 1300 or 1400 deg F, respectively; if you don’t like flame. Otherwise, get some Kasenit and a torch and follow the directions.
This leaves a higher-carbon surface on the steel is much harder than the steel under it. How hard? I have no idea. If I ever were to do this, I might check into how hard the Kasenit makes a nail.

You’ll be making one at a time. So this part if for the motivated person with some time to kill.

2. Make the jacket
Get a Corbin Swage or some premade 308 jackets and set them in a holder of some sort, point down; ready to be filled.

3. Fill the point
Use pure lead ingots, or scrap lead that has been purged of junk (rocks, sand, bits of copper jacket, etc.), or maybe even Cerro-Safe casting metal since it melts at only 170 degrees
Melt the metal of choice and fill the empty jacket maybe 1/3 of the way, maybe 1/2? I dunno, this is all an educated guesstimation.
While the lead is still molten, push the homemade penetrator down into it. Ideally, the penetrator will center itself in the nose of the jacket and the lead will come up and fill the space alongside the penetrator between the jacket flow up and over the base of the penetrator. So when the lead hardens, it will hold the whole thing together.

OK, so this core isn’t exactly bonded to the jacket. Maybe a core-jacket separation will be OK for the purpose of having a multi-purpose round: one that will shred apart (expansion, though not controlled) and still let the penetrator go on to find deeper places to exist.

All this is just my brainstorming. But if anyone tries it, please send it to the Box’o’truth or something and let us know how it worked!

C-

 

[El Tejon]

"If you see sparks, whack him again." Clint Smith on encountering armour with rifle fire.

I like stuff like the Bundeswehr .308. Mild steel core that still comes apart. 155 grain TAP seems like it would be good stuff, have never shot anything with it.

Ammo, like firearms, is just a tool and it's hard to find a perfect compromise tool. That's why the sheet of pegboard is so full.

 

[Jim Watson]

Back in the days when the American Rifleman was a technical journal, there was a short piece that concluded that a cast zinc bullet would penetrate "firm" material like wood about like AP. It would not cut steel like the hard cored GI load, of course.

 

[Coronach]

How well does the 155gr TAP round penetrate through cover? Anyone know if Box O Truth has looked at that?

And I agree, to my semi-trained pseudo-scientific eye, that 155 gr TAP round seems to be a nice compromise between penetration in flesh and immediate massive wound.

Mike

 

[Lucky]

cpileri that's a good idea, but it's complex and my experience is that it is less likely to work properly because of that.

However if you look at the old Pig Board experiments and others, you can get awesome penetration from switching to bronze instead of lead. Just make all-bronze bullets (copper & little tin). They will be difficult to cast, probably shrinking and stuff so that's out. But using a lathe wouldn't be impossible. Short-range bullet to be sure, but that's about the only time they make sense for use in something other than a dedicated AP weapon.


I believe most laws make THV/Monad bullets illegal in some manner, but read this site: http://www.quarry.nildram.co.uk/THV.htm

They got pistols punching armour plate like only rifles should.

 

[alucard0822]

I think for SHTF/deployment type scenarios those 155gr tap loads, or federal 168gr match (SMK) would be my choice, I know the fed gold match will go boom, pacs a decent ammount of weight, and has about the best long range accuracy of anything I have tried. I would rather pick BGs off at 500+ yards anyway. Any 308 will cut through a vest, car door, or light cover, that is all I think I would need. If I encounterred anything where I would NEED AP ammo, I think I would be better off hiding, or running away maybe see if one of my friendly neighborhood pilots could bring some JDAMs or 30mm cannon fire to the party.

 

[Lucky]

There was a good story a while ago on this site, where a guy gets a phone call from a buddy telling him there's a nuclear attack warning for his city, but he and his family are so slow getting ready that he gets stuck in traffic trying to leave, and the whole situation is pretty SHTFish. No-where were there needs for 500m shots

 

[gunnie]

500 M/yds

i agree with alucard, i'd rather whack adversaries @ 500yds.

i also agree with lucky, in this being an unlikely scenario.

in spite of SGN "fred's" [www.fredsm14stocks.com] urgings, most semiauto 308's and their operators aren't up to the task.

his allotment for rifles is that all they need to be capable of is 4"@100yds....{on paper, 4" X 5 [C yds] = 20"}.....but realisticly, in ANY kind of wind, up or downhill, non magnified sighting or low powered combat optics, a target in camo, or taking cover or running straight or erratically..etc...GOOD LUCK. add to this the nearly non-existance of 500 M/YD ranges where joe average gets to play. how many kids do YOU know who can range 500 without a laser? how many sillyvillian/commercial lasers will range a non-reflective target @ 500?

sure, MANY semi(s) will do half the four inch variable, and good ones half of that. but when SHTF, the sand bagged bench, and the state of calm (wind AND operator) that translates into long range accuracy will likely not be there.

but in agreement with SGN "fred's" premise, some battle rifles/people are.

most armies around the world have gone to the commie docturine of ground pounders being little more than "eyes" for artillery and air power. this has lead to the creation of small caliber and/or short range iron, and little training for even what ranges they are capable of.

locate, radio, suppression fire till the heavy metal comes flying in.

any point, here?

....practice for both possibilities....

gunnie

YOU CAN'T MISS FAST ENOUGH TO WIN!!!