Ok, I've read a bit about this, but obviously not enough. So....

I've got an AR15 14.5" 1/9 twist. Which grain would be better for 100-300 yards on soft targets, 55 or 62 grain? And this may sound silly, but how about beyond 300 meters? I've got plenty of 55 grain stuff and I'm wondering if I'm just as well off with it, or if I should be stocking up on more 62 grain? Suggestions?

The twist of your barrel indicates that it should properly stabilize the 62 grn.

In my unqualified opinion the twist rate of the barrel much more determines bullet weight as opposed to barrel length.

The barrel length will more determine velocity.  At 14.5" you are right on the edge of enough velocity to generate adequate kill-power.

Were I in a situation where my as* depended on my rifle I would shoot with a minimum 16" barrel plus suppressor and if possible I would move to an 11:1 maybe 12:1 twist barrel and shoot 55grn bullets.

I am a 1 ammo man - I shoot a 14.5 Colt LE6921 (1:7) - I have used it in service rifle competitions to 500m with SS109.
I just could not be bothered to stock 2 types of ammo - although the difference in the 100-300m is so negligable that if you had a source of cheap 55gr it might be worth while using instead of SS109

sea,

Whichever round is more accurate is in your rifle is the one to use.

"Killing power?"  The effectiveness of any bullet against a living target is based solely on bullet placement, penetration and the interface between the permanent wound channel(s) and vital organs and vessels or the central nervous system.

If you feel that a bullet must fragment violently to be effective, you are stuck in the 70's with a variation of the thoroughly debunked Relative Incapacitation Index.  

Bravo!

This is another of those "genius" arguments without any geniuses - especially me.  As I noted in my first post my opinion was offered as "unqualified."

However Dave_G chooses to put forth his argument without qualification.  His opinion is the only one correct.

I'm not certain who Mr. G accuses of being "stuck in the 70's" and who feels "that a bullet must fragment violently to be effective ?"

The ever knowledgeable Mr. G states that "solely [bullet] placement......."

The Army moved from the .308 round more because that round was likely to go through the target and expend the majority of its' energy down range than because more .223 ammunition could be carried.

The .223 SCHV (Small caliber high velocity) round was more likely to expend its' energy within the target.

Please note that "high velocity" is part of the equation.  With proper velocity (a function of both ammunition, barrel and barrel length) the .223 round can be fatal from a shoulder, arm, hand and sometimes even a finger hit (rarely) as the high velocity round can set-up a hydrostatic shock wave moving through out the body and stopping the heart.

In Mr. G's perfect world of perfect soldiers placing perfect hits only a .22 single shot rifle is needed.  You might consider informing the Armed Forces and saving all of us tax payers
millions of dollars in unneeded complex rifles and ammunition.

Finally the most accurate bullet in your particular rifle is not refutable.

ovarb

Quoted: the .223 round can be fatal from a shoulder, arm, hand and sometimes even a finger hit (rarely) as the high velocity round can set-up a hydrostatic shock wave moving through out the body and stopping the heart.

You can't be serious with this.  This was debunked over a Decade ago.  Dammage is what counts period.  Under the right conditions (velocity & enough flesh for the round to penetrate) 5.56 M913/M855 can cause some pretty serious wounds, but 'Hydrostatic Shock'?  Thats Sci-Fi not science.

Check out some of the links posted here:
communities.msn.com/TheMarylandAR15ShootersSite/advantagesof556references.msnw pay particular attention to link#3.

Using 62 grain stuff in a 14.5 inch barrel limits you to a fragmentation range of less than 60 yards.

Use 55 grain in your short AR's.  It will be more effective.  Speed is the limiting factor in short AR's.  Don't even think about shooting 300 yards.  A short AR is not properly suited to the role.  Get a 20" barrel if you want effective shots out to 300 yards.

BTW - by 'effective' I mean fragmentation, so none of this shot placement crap.  Everybody knows this already.

Edited cause I typoed...

sub,

Bullet length, not necessarily weight, dictates the rifling twist rate for proper stabilization of the bullet.  A 1/9 twist is just fine for M193 and M855 rounds and other bullets of comparable length.

As for your response to my post, well, I am correct.  Period.  The effectiveness of any bullet against a living target really is based solely on bullet placement, penetration and the interface between the permanent wound channel(s) and vital organs and vessels or with the central nervous system.  That paraphrases Dr. M. L. Fackler and many, many others, some more and some less knowledgeable than I.  

The energy transfer theory is just a big steamin' pile of "hooey" just like the hydrostatic shock killing with a finger hit is.  Those were myths and wild, uneducated theories advanced by well-meaning folks who had no idea why the 5.56mm round performed as it did in some cases until Dr. Fackler did his work.

Bud, a CNS hit at 500 meters with an M855 round can kill an enemy soldier just as dead as one at one meter.  Placement, penetration and damage done to vital organs, vessels and/or the central nervous system has been and always will be the key.

Quoted: Placement, penetration and damage done to vital organs, vessels and/or the central nervous system has been and always will be the key.

Well said!

I use M193 Ball almost exclusively with M855 Ball as secondary ammo.

Rifling twist requirements are a function of bullet length, not mass [weight]. Longer bullets are heavier, of course, but the twist needed is related to the length vs. diameter.

The US Army never used .308 of course. We did, however, go from 7.62mm to 5.56mm in the mistaken belief that "striking energy" was a meaningful measure of "killing power" and that there was a floor level (I recall it was 60 lb-ft) that needed to be achieved. Surprisingly the research published in the 1980s has failed to reach the gloss gun magazines which continue to publish "energy levels" for cartridges -- OK, they're easy to compute. As are other bogus indexes and formulas. To include "absorbed energy."

A broad point hunting arrow, capable of killing all North American big game has the energy of a .22 Short fired at close range. Certainly there must be a different factor working here than "absorbed energy." That factor is damage.

For standard military ball and its commercial sisters, there is no benefit in a looser rifling twist than 1/9 or even 1/7. 1/12 has no advantage even with 55gr M193 Ball and is not capable of shooting longer M855 Ball accurately. 1/11 would be an expensive custom job producing no advantage (other than to the pocket of the custom barrel shop).

Hydrostatic shock is indeed science fiction. Not to be confused with hydrostatic lock, a very real problem, but not in firearms unless they're fired under water.

Larger wounds have more potential for more damage.  US 5.56mm military ball ammo at combat ranges has the potential for producing 6" diameter wound channels 5" to 18" within animal tissue.  This is potential, not certainity.  A 5.56mm wound in the hand, arm, leg, etc where a major bone or artery isn't struck is usually a two band-aid wound.

Shot placement, while a goal is highly illusive in combat shooting.  When the location on the body where rifle bullet wounds occur is analyzied and compared to a random pattern they're almost identical.  While you may aim center of mass, you can't be sure you'll hit center of mass.  Increase your odds by making large holes.

-- Chuck

I think I need to seek the assistance of a good cardiologist.  I find myself in complete agreement with Chuck's post.  Somebody call 9...1...

OK.  So much for the fun.

By shot placement, I meant where it actually hits, not necessarily where it's aimed.  The biggest holes in the right places are always good, and big holes anywhere in the lower torso and thighs, while not necessarily the best, are at least acceptable as long as they put the bad guy down fairly quickly and before he can do significant further damage to the good guys.

Quoted: Using 62 grain stuff in a 14.5 inch barrel limits you to a fragmentation range of less than 20 yards. Use 55 grain in your short AR's.  It will be more effective.  Speed is the limiting factor in short AR's.  Don't even think about shooting 300 yards.  A short AR is not properly suited to the role.  Get a 20" barrel if you want effective shots out to 300 yards. BTW - by 'effective' I mean fragmentation, so none of this shot placement crap.  Everybody knows this already.

I dunno about any of you guys but here is my choice: I stick with what the pro's use.... The Special Forces guys have been in a few more gun battles than most of us. They are using the M4 with a 14.5" barrel and SS109 62gr. They use a 1:7 twist (1:9 was designed to be a compromise for 62gr & 55gr, which fires best from 1:7 and 1:12 respectively) Hell, those fancy $700 ACOG TA01NSN's BDC is calibrated for 62gr. fired from a 14.5" barrel. The BDC on those is calibrated out to 600 meters so don't even tell me you can't effectively engage targets with an M4 out to at least 500 meters with fatal or near fatal results. If you can't.... start working on your marksmanship instead of the "Spray and Pray" method you're using now! Which takes us back to the whole "shot placement" arguement. It doesn't matter if you're using a .50 BMG... if you can't hit the target you can't kill it.

For CQB training I use 55 gr. since it is cheap and readily available at the local gun shop and at 25 meters and under it makes no difference punching paper torso cut outs. For 100 meters and beyond I use SS109 and my ACOG.

There is my $0.02 for what it's worth.

Quoted: I dunno about any of you guys but here is my choice: I stick with what the pro's use.... The Special Forces guys have been in a few more gun battles than most of us. They are using the M4 with a 14.5" barrel and SS109 62gr. They use a 1:7 twist (1:9 was designed to be a compromise for 62gr & 55gr, which fires best from 1:7 and 1:12 respectively)

Well unless you are in a fireteam with a SAW or two you don't need the M855.  Its easier to just issue 1 ammo type (M855) to everybody than to issue the M4s with M193 and the SAWs with M855.

1:7 twist is not optimal for the 62gr, 1:9 is much better.  The 1:7 twist is to stabilize the M856 tracer rounds, so unless you are shooting tracer rounds you don't need the 1:7.  By using the 1:9 your barrel will actually last a bit longer.

In other words they have needs and requirements that you won't have to face.  You can opt for the better performance so why not?

Quoted: The BDC on those is calibrated out to 600 meters so don't even tell me you can't effectively engage targets with an M4 out to at least 500 meters with fatal or near fatal results. If you can't.... start working on your marksmanship instead of the "Spray and Pray" method you're using now! Which takes us back to the whole "shot placement" arguement. It doesn't matter if you're using a .50 BMG... if you can't hit the target you can't kill it.

Your informational void is only matched by the sheer idiocy of your arguements.

The speedometer on your car might go up to 120MPH, but that doesn't mean anything as far as vehicle performance, or intended role.

M4s are used primairly as close combat weapons, where engagements are expected to be less than 100 yds.  M4's are issued to special forces, not regular infantry on a regular basis.

Regular infantry is issued M16A2 in a 20" config for the most part, and this is for a reason.  Velocity is higher.  Accuracy is better.  Bullet flight is flatter.

Sure the M4 can reach out to 500m accurately, but that is not their primary role!
Besides, at those velocities, you would be better served by using a 9mm or other round.

A .22LR can kill out to a mile, but I would rather take my .50BMG anyday.  

The only spray and pray I have ever done, is when I am peeing near an electric fence.  

Wild accusations are always irresponsible.

Well I've read all of the above and find none of it really applies to me anyway.

My engagement range is always fifty-yards and I always shoot the target directly through the left eye.  Looks as if my single shot .22 may be more than I need.

After this enlightening I'm considering adjusting my engagement range down to always 25 yards and always shooting the target through both balls and getting a single shot CO2 pellet gun.

I've not had much time to consider this next option but I "wonder" if I adjust my engagement range to always 5 yds maybe I can use an air-Soft paint ball gun and always shootem in their always open mouth ?

After all only projectile placement matters.

I mean I could wonder why my 66SP sniper has a
1:11 twist or why the Springfield Armory rifles move between 1:10 - 1:12 but why ?  I've finally learned that none of this matters.

Well, I'm off the the 70's.

Actually, DarkHelmet is only wrong on the ideal twist rate for M193, M855 and M856 which Forest corrected.  Whether "the pros" get to choose their weapons and ammo, or understand the wounding mechanisms of the ammunition, they use what they use.

Torf, on the other hand, doesn't seem to understand that a CNS hit at 500 meters from an M4 can kill a man really dead and the TA01NSN ACOG significantly increases the chance of that telling hit at the aforementioned range.  Primary role be damned, if the enemy rears his ugly head at 500 meters and all your longest reach is an M4, you take the shot.  A 9mm?  Huh?  Shoot a 9mm pistol round at a target 500 meters away?  

Next "the never wrong" Dave_G, will explain "......kill a man really dead....."
This obviously totally depends on shot placement
as the unfailing Dave_G previously explains.

UMMMMMMMM
HMMMMMMMMMM   "really dead" vs. dead.
             "really dead" vs. only dead
             "really dead" vs. deader
             "really dead" vs. deadest

Dave_G - there may be an entire book you can write on this brilliant statement.

While Ex. Clinton struggles to define "IS" you only have to explain "really dead."
This should be no shot for a shooter.
UMMMMMMMMMMM
HMMMMMMMMMMMMMMMM

Are you feeling a bit inferior tonight, sub?

Nope, that's not the definition of "really dead" Dave_G.

From the above "poster herd" I've learned twist-rate doesn't matter.

Sitting around this AM reading my new issue of "Small Arms Review" Vol.5 No.4 and find an interesting article on the "FN Special Police Rifle."

Twist rate + 1:12  Bullet weight 168 grns.
Average group size + .75 MOA.
Not bad for a chrome-lined barrel rifle with a retail of $940.00 and LEO price of $740.00

ArmaLite AR-10(T)
Stainless barrel Twist rate of 11.5  bullet weight 168 grn.

My Israeli Sniper 66SP
Twist rate 11:1   Bullet weight 168 grns.

Now with such company as FN, Small Arms Review,
Mauser and ArmaLite maybe living in the 70's isn't so bad.

These folks all seem to believe barrel twist, bullet weight and velocity actually matter.

Misguided fools that they aren't.

I'm still waiting on the definition of "really dead" - after all you are infallible.

Quoted: Sitting around this AM reading my new issue of "Small Arms Review" Vol.5 No.4 and find an interesting article on the "FN Special Police Rifle." Twist rate + 1:12  Bullet weight 168 grns. Average group size + .75 MOA. Not bad for a chrome-lined barrel rifle with a retail of $940.00 and LEO price of $740.00 ArmaLite AR-10(T) Stainless barrel Twist rate of 11.5  bullet weight 168 grn. My Israeli Sniper 66SP Twist rate 11:1   Bullet weight 168 grns.

UHHH point of fact these are all .308 rifles.  Twist rate is dependant on the bullet length  The length of a .308 168gr bullet is different from the length of a 62gr 5.56mm SS109 projectile.  You are comparing apples to radishes.

These folks all seem to believe barrel twist, bullet weight and velocity actually matter.

And what does this have to do with any of the information you presented.

So .308 caliber rifles shooting 168gr match bullets like twist rates between 1:11 and 1:12??  Ok.. 5.56mm rifles shooting 80gr match bullets like twist rates between 1:7 and 1:8.5

None of this has anything to do with performance on soft targets.  Twist rate does not influence dammage.  It only allows the bullet to stabilize and thus fly true.  A 1:9 twist adequately stabilizes a 55gr round.  According to Dr. Fackler (see above links), twist rate of the round is irrelavent to damage caused.

Let's see...Somebody doesn't have a clue what "really dead" means...

How's this?  No pulse, no respiration, no brain activity, a foul stench hanging about the unmoving body, maggots dining in...and out.

You have basic information available to you.  You just need to learn how to apply it and turn it into knowledge.

Quoted: Ok, I've read a bit about this, but obviously not enough. So.... I've got an AR15 14.5" 1/9 twist. Which grain would be better for 100-300 yards on soft targets, 55 or 62 grain? And this may sound silly, but how about beyond 300 meters? I've got plenty of 55 grain stuff and I'm wondering if I'm just as well off with it, or if I should be stocking up on more 62 grain? Suggestions?

Seven grains of weight make very little performance difference, given the designs of the bullets.

The best would be what is in your mags.  You can't miss fast enough to win.  Frontsight and trigger control.

SRM

Quoted: Seven grains of weight make very little performance difference, given the designs of the bullets.

But the velocity of the 55gr load & that of the 62gr load IS very different, especially out of the 14.5" barrel.  Terminal performance at 100yards will be VERY different.

However the difference is not important for accuracy concerns under 300M.

Terminal performance of M193/M855 under 100 meters can be very different depending on what part of the body and the type of tissue that's hit.

Well, Dave_G and his little buddy Forrest.  How cute.

Let's see Dave_G seems as if you've defined "dead" adequately but the question was "really dead."

From Forrest we have "twist rate is dependent on bullet length."
Forrest since you're carrying Dave_G's dirty jock strap I believe bullet length is probably dependent on twist rate.  Course I'm probably wrong.  You see I believe it's probably easier to change bullets than change the twist of the barrel.  You're discovery that a .308 was longer than the 5.56 was startling - to say the most.

Well anyway I was headed back to the 70's when I took a rest stop along the way.


"Later carbines were developed which featured 14.5" barrels.  These longer barrels work much better with the M-16 gas system and retain more of the 5.56mm cartridge's effectiveness.  This a round that RELIES UPON HIGH VELOCITY FOR EFFECTIVENESS.  WOUND BALLISTICS ARE COMPRIMISED WHEN THE VELOCITY FALLS BELOW 2500fps."

"The .223 cartridge must retain 2500 fps or more muzzle velocity to retain its lethality."
(SAR Vol. 4 No.5)

These folks are as dumb as me.  They think velocity matters.
(I must confess they did not define "really dead.")

Well, I'm heading on toward the 70's.

seamusmcoi, Dave_G, Forrest,
mommy call you little boys for din din ?
Tell me do you three hold hands when you skip ?

I believe I can depend on you "boys" to continue your brilliant and unsubstantiated posting far into the future providing a fine  opportunity for free entertainment.

Only the three of you in your little gang ?  I'd have thought your rat-pack would have at least six so you wouldn't be afraid to go to the corner store.  That business about safety in numbers isn't really true.

Get it seamusmcoi ?

Later.  

Well, well Dave_G,
looks as if you have a couple of logos - one for harassment and one for uh uh uh "Moderator?"
Kinda like two faces huh Dave.
Maintenance and Cleaning - how appropriate.  Well a woman's work is never done.
 

sub,

I moderate two forums, Maintenance & Cleaning and Brothers of the Shield.  Elsewhere on AR15.COM, I'm just another paying member.

As for harrassment, I don't think your posts rise to the level of harrassment since they seem to be nothing more than juvenile attempts to engage me in a "pissing contest."  This causes me to bring to your attention to the Forum Conduct Code, specifically, paragraphs 4, 6 and 7 as follows:

4) No pissing matches. Its fine to disagree, but once a thread has run its course, and degenerated into little more than an insult fest, it will be locked. 6) Pure trolling. Either to piss someone off or simply for your personal enjoyment. If you're here to cause trouble, it will be a very short stay. 7) No personal attacks towards ANYONE. If you have a problem with someone, then take it offline with them. If it's with a member of the staff or a moderator, then contact someone from the Senior Staff. Attacking a person, ANY PERSON, in a non-joking manner (clearly visible as a joke) will not be tolerated. Joking and teasing are fine, but if you cross the line, apologize before things get worse. This includes provoking someone into an attack.

This topic has run its course.  It's time to end it.

Quoted: seamusmcoi, Dave_G, Forrest, mommy call you little boys for din din ? Tell me do you three hold hands when you skip ? I believe I can depend on you "boys" to continue your brilliant and unsubstantiated posting far into the future providing a fine  opportunity for free entertainment. Only the three of you in your little gang ?  I'd have thought your rat-pack would have at least six so you wouldn't be afraid to go to the corner store.  That business about safety in numbers isn't really true. Get it seamusmcoi ? Later.

No.



Do you have a hamster stuck up your ass or what dude? At this point your just responding to yourself. And I have no idea why you think that three members here have suddenly conspired against you. Two people simply disagreed with you, and I simply asked a seperate question.

Are you high on meth or what? This kind of paranoia is symptomatic of that kind of logic.

Dave_G has spoken.  It's time to end !!
Did you explain that the end was here to your "boy" seamusmcoi ?

If you two think you can insult with out retort think again.  (After all I may be high on meth).

Tell me Dave_G is insinuating that I'm high on meth permissible under the rules of conduct ?

I know the "hamster" stuck-up my ass must be permissible - right Dave_G ?

I'm putting a lock on this and let you guys cool down a little.  Not a bad topic just hold the discourse to a more civil level.

Arock out.