M193 or M855 SS109


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Roadwild17
October 16, 2008, 07:28 PM
If you were getting ~ 3K in a week, would you get M193 or the SS109 steal penetrator.

It would be used for plinking, training, general stash to have for surviving huge price increasses, whatever.

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dodging230grainers
October 16, 2008, 07:36 PM
M193. Best all purpose round.

Better and more reliable fragmentation (5.56 destruction mechanism) at ALL ranges. Also cheaper to buy and stockpile. Also more common, so if you find spare ammo during SHTF, you're rifle will be zeroed with M193 already.

M855 was created during the cold war to be able to meet NATO standards (to be able to go through a Soviet soldier's helmet at 600 yards.) You basically gain more long-range penetration and retained energy and sacrifice unarmored terminal effectiveness. Besides, at 600 yards, you should be using your bolt action .308 anyways.

I highly suggest Winchester Q3131 5.56mm 55 grain FMJ. I have 2k rounds of it. It is the closest thing to real milspec M193.

Ghost Walker
October 16, 2008, 08:04 PM
What is the rifling twist rate of your AR's barrel?

M193 (55 grains) will shoot through just about any twist barrel; but, it does better out of slower 1:12 - 1:9 twists. A 1:7 twist can accelerate M193 fast enough to destabilize or even explode the bullet shortly after exiting the muzzle.

M855 is an American designation for NATO 5.56x45mm ammunition. Problem is that American M855 is more powerful than NATO SS109 ammunition supplied for: British, Canadian and Dutch rifles. Personally, I look for ammunition that's been manufactured within the last 20 years and carries the dual designation M855/SS109. (Lake City!)

I'm shooting two 1:7 twist AR barrels so I'm going to get the best results with 61.5 grains bullets and above. I usually look for recently manufactured government issue or Federal American Eagle 5.56x45mm ammunition; and I tend to stay with 62 - 68 grain bullets. I don't really care about core penetrators. If I get them, fine. If I don't, that's still OK.

longdayjake
October 16, 2008, 08:13 PM
Most people get better groups with the m855. I think my ar has shot about 120 rounds of 193 and about 2000 rounds of m855. I liked them both. m193 is cheaper though so if all you want to do is pull the trigger and hear a bang then I would go with m193. The m855 is more in demand so if you stock up on it now it may really get out of control price wise and you can sell some of it and buy another toy.

Marcus L.
October 16, 2008, 08:22 PM
If you are talking plinking and training, either would be fine. However, if you are thinking that either would be a dependable combat load, I wouldn't put that much confidence in it. Here's a good post on the 5.56 M193/M855 by Dr. Gary Roberts:

"As I recently stated in my presentation at the NDIA in Dallas this past week, 5.56 mm NATO 62 gr SS-109/M855 FMJ was designed over 30 years ago as linked machine gun ammunition to be fired from the FN Minimi/M249 SAW while engaging enemy troops wearing light body armor during conventional infantry combat at distances of several hundred meters--while not a perfect solution, M855 does perform adequately in this role.

Unfortunately, combat operations since late 2001 have again highlighted terminal performance problems, generally manifested as failures to rapidly incapacitate opponents, during combat engagements when M855 62 gr “Green Tip” FMJ is fired from 5.56 mm rifles and carbines. This is not surprising, since M855 was not originally intended for use in carbines or rifles, especially those with short barrels. In addition, most current issue 5.56 mm bullets are generally less effective when intermediate barriers, such as walls, glass, and vehicles shield opponents--this is a significant consideration in urban combat.

As an interim solution to these problems, deployed SOF units have used 5.56 mm Mk262. The Black Hills produced Mk262 uses the 77 gr Sierra Match King (SMK) OTM and is built as premium quality ammunition intended for precise long-range semi-auto rifle shots from the Mk12 rifle. It is great for its intended purpose. Mk262 has demonstrated improved accuracy, greater effective range, and more consistent performance at all distances compared to M855 when fired from current M16, Mk12, M4, HK416, and Mk18 rifles and carbines. However, despite this substantially improved performance, Mk262 still manifests the problems of poor intermediate barrier penetration and somewhat variable terminal performance inherent with the SMK design.

The disturbing failure of 5.56 mm to consistently offer adequate incapacitation has been known for nearly 15 years. Dr. Fackler’s seminal work at the Letterman Army Institute of Research Wound Ballistic Laboratory during the 1980’s illuminated the yaw and fragmentation mechanism by which 5.56 mm FMJ bullets create wounds in tissue. If 5.56 mm bullets fail to upset (yaw, fragment, or deform) within tissue, the results are relatively insignificant wounds, similar to those produced by .22 LR--this is true for ALL 5.56 mm bullets, including military FMJ , OTM, and AP, as well as JHP and JSP designs used in LE. This failure of 5.56 mm bullets to upset can be caused by reduced impact velocities when hitting targets at longer ranges, as well as by the decreased muzzle velocity when using short barrel carbines. Failure to upset can also occur when bullets pass through minimal tissue, such as a limb or the torso of a thin, small statured individual, as the bullet may exit the body before it has a chance to upset. Finally, bullet design and construction plays a major role in reliable bullet upset. Without consistent bullet upset, wounding effects are decreased, rapid incapacitation is unlikely, and enemy combatants may continue to pose a threat to friendly forces and innocent civilians.

Angle-of-Attack (AOA) variations between different projectiles, even within the same lot of ammo, as well as Fleet Yaw variations between different rifles, were recently elucidated by the JSWB-IPT. These yaw issues were most noticeable at close ranges and were more prevalent with certain calibers and bullet styles—the most susceptible being 5.56 mm FMJ ammunition like M855 and M193. What this means is that two shooters firing the same lot of M855 from their M4’s with identical shot placement can have dramatically different terminal performance results: one shooter states that his M855 is working great and is effective at dropping bad guys, while the other complains his opponents are not being incapacitated because M855 is zipping right through the targets without upsetting. Both shooters are telling the truth…"

Dr. Fackler also worked on a number of Vietnam M193 wounds up until the M855 was adopted and there was a good number of them when fired from a full length M16 20" failed to upset and cause fragmentation. So, the resulting wound was a little keyhole that didn't do a whole lot of wounding. The 5.56 is sporatic with fleet yaw and is MUCH better with soft points, OTM loads, or hollow points.

Here's a link to more on the subject:
http://www.dtic.mil/ndia/2008Intl/Roberts.pdf

There are a lot of cheap soft point, OTM, and hollow point 5.56 loads out there that would be better for defensive use than the M193 and M855. I suppose that if I had to use one for defense, I would choose the M193 though.

RyanM
October 16, 2008, 08:32 PM
A 1:7 twist can accelerate M193 fast enough to destabilize or even explode the bullet shortly after exiting the muzzle.

Uh... huh. This is at what velocity, now? 4,000 fps? 5,000 fps? More?

According to the US Army, on the other hand, using ammunition and weapons which actually exist:

(1) The increase in projectile length, weight, and configuration of the M855 bullet requires different twists in the barrels, lands, and grooves to stabilize the bullet in flight. The M16A1 has a 1:12 barrel twist (the bullet rotates once for every 12 inches of travel down the barrel). The M16A2/A3/A4 and the M4 carbine has a 1:7 barrel twist (the bullet rotates once for every 7 inches of travel down the barrel).
(2) The M16A1, with its 1:12 twist, does not put enough spin on the heavier M855 bullet to stabilize it in flight, causing erratic performance and inaccuracy for training or full combat usage (30.48- to 35.56-centimeter shot group at 91.4 meters and 72-inch shot group at 274.2 meters) (Figure 5-33). Although firing the M855 cartridge in the M16A1 rifle is safe, it should only be used in a combat emergency, and then only for close ranges of 91.4 meters or
less.

http://www.thehighroad.org/attachment.php?attachmentid=86525&stc=1&d=1224199822

(3) The M16A2 rifle with its 1:7 twist fires both types ammunition with little difference in accuracy to a range of 500 meters. The M16A2 and its ammunition are more effective at ranges out to and beyond 500 meters due to a better stabilization of the round.
(4) The two 10-round shot groups in Figure 5-33, A were fired by a skilled marksman at a distance of 274.2 meters using the same M16A1 rifle. The 25.4-centimeter shot group on the left was fired (and zeroed) with M193 ammunition. The 6-foot shot group on the left was fired with M855 ammunition.
(5) Figure 5-33, B shows two 25.4-centimeter shot groups fired by the same skilled marksman at a distance of 274.2 meters using an M16A2 rifle. The shot group on the left was fired (and zeroed) with M855 ammunition. The shot group on the right was fired using M193 ammunition.
(6) As stated previously M193 and M855 ammunition can be fired from an M16A2-/A4-series weapon. Table 5-4 and Figure 5-34, page 5-34, show the difference between a rifle zeroed with M855 ammunition and then re-zeroed with M193 ammunition at 300 meters. There is practically no difference between the trajectory of the rounds or the impact of the rounds on target.

--------------------

Anyway, are those really your only options? I'd try to stockpile some sort of lower cost OTM ammo in a weight that's optimal for your rifling. Personally, I ended up getting half Wolf 75 gr JHP, and half Prvi 75 gr OTM.

Ghost Walker
October 16, 2008, 10:12 PM
http://en.wikipedia.org/wiki/Rifling

If an insufficient twist rate is used, the bullet will begin to yaw and then tumble; this is usually seen as "keyholing", where bullets leave elongated holes in the target as they strike at an angle. Once the bullet starts to yaw, any hope of accuracy is lost, as the bullet will begin to veer off in random directions as it precesses.

Conversely, too-high a rate of twist can also cause problems. The excessive twist can cause accelerated barrel wear, and also induce a very high spin rate which can cause high-velocity projectiles to disintegrate in flight. A higher twist than needed can also cause more subtle problems with accuracy: Any inconsistency within the bullet, such as a void that causes an unequal distribution of mass, may be magnified by the spin.

Undersized bullets also have problems, as they may not enter the rifling exactly concentric and coaxial to the bore, and excess twist will exacerbate the accuracy problems this causes. Lastly, excessive spinning causes a reduction in the lateral kinetic energy of a projectile, thereby reducing its destructive power (the energy instead becomes rotational kinetic energy).

gvnwst
October 16, 2008, 10:15 PM
M193 is a fairly strong round, one that would not 'blow up' in a 1-7 barrel. that said, i chose the 62 ss109. i like the extra bc the bullet has.:D i shoot long range better.

HorseSoldier
October 16, 2008, 11:28 PM
Never had a problem with real USGI M193 or any other 55 grain loads I've shot along the way (everything from Wolf to Black Hills) losing accuracy or just flying apart out of the barrel from 20", 16" or 14.5" barrels.

If you're looking at buying a stash of pre-Obama ammo, I'd go with the SS109, which has the potential to be banned if an Obama ATF decides that steel core makes it "armor piercing" and such. 55 grain FMJ ain't going anywhere unless they try to just ban or tax all ammo out of existence.

As for lethality -- good training leading to good shot placement means more than the internet hysteria for bullet fragmentation velocities. But, if you're inclined to worry along those lines, Mk 262 beats either round on lethality, as do some good commercial loads.

stubbicatt
October 17, 2008, 08:10 AM
The ammo with steel cores or steel jackets is sometimes not allowed on various ranges. Often "practical" matches won't let you shoot it at their steel targets, and I've been told it will penetrate right through a baffle or a bullet trap at many indoor ranges.

If you don't have these concerns, then I suppose the SS109 would be a good choice too.

I have found that the 55 grain FMJ Hornady bullets are quite accurate, compared at least to some other manufacturers.

Sam Adams
October 17, 2008, 01:29 PM
A lot of ARs don't have 1:7 twist rates, but 1:9. This probably makes the 69 grain Sierra bullets the best for accuracy, not the 77 grainers. Of course, every rifle is different, so test on yours.

I'd advise everyone here to handload - the equipment doesn't cost much, and you will both save money on each round and build more accurate ammo for your specific rifle.

RyanM
October 17, 2008, 07:28 PM
Conversely, too-high a rate of twist can also cause problems. The excessive twist can cause accelerated barrel wear, and also induce a very high spin rate which can cause high-velocity projectiles to disintegrate in flight.

(1) Wikipedia is not always a reliable source of information
(2) That article does not mention M193 out of a 1:7 twist
(3) About the only way to "blow up" a bullet with excessive twist is to use something insane, like a 40 gr varmint bullet at 5,000 FPS or more. That takes a lot more juice than 5.56mm is going to put out. I have heard of hot wildcat calibers like .22-06 (full length, not short) doing it, though. But only with thin-jacketed varmint bullets.

paratroop23
October 17, 2008, 09:25 PM
My rifle has a 1:7 twist, so I know it can stabilize both the m193 and m855 but I'm sticking with the 62gr m855.

Onmilo
October 17, 2008, 09:33 PM
Neither.
I use 62 grain Lead Core full metal jacket, but all my rifles are 1/10" or faster twist.
If you have an older 1-12" twist rifle then stick with the M193 FMJ ammunition.
The 62 grain steel penetrator ammunition is about as inaccurate a bullet as you can get.

If you have a fast twist rifle, 1-8" or 1-7", try to find a deal on Black Hills or Federal 77 grain Sierra match ammunition or better yet,
Privi partizan is offering a 75 grain FMJ load that is almost as accurate and is much better priced.

Oh, 55 grain FMJ bullets will not blow up coming out of a 1-7" twist barrel, they just won't shoot very accurately past 100 meters.
I haven't been impressed with the performance at 100 meters personally.

stubbicatt
October 18, 2008, 09:08 AM
About the only way to "blow up" a bullet with excessive twist is to use something insane, like a 40 gr varmint bullet at 5,000 FPS or more. That takes a lot more juice than 5.56mm is going to put out. I have heard of hot wildcat calibers like .22-06 (full length, not short) doing it, though. But only with thin-jacketed varmint bullets.

I guess my experience defies your assertions, as the thin jacketed varmint bullets in my 223 Krieger barreled 1 in 7.8" twist rifle would often explode in a grey puff at about 40 yards from the muzzle. So I've actually seen this phenomenon as it has happened to me.

YMMV

Ghost Walker
October 18, 2008, 10:32 PM
I guess my experience defies your assertions, as the thin jacketed varmint bullets in my 223 Krieger barreled 1 in 7.8" twist rifle would often explode in a grey puff at about 40 yards from the muzzle. So I've actually seen this phenomenon as it has happened to me.

:) Now, now, remember where you are! This is the internet where things can get surreal fast. ;)

Your experience is another of two or three incidents I've read about where a 5.56 bullet exploded shortly after leaving the barrel. The other two did, in fact, involve M193; and, for awhile, one was listed in Ammo Oracle.

Yeah, Wikipedia isn't always reliable; sometimes it can be outright lies and distortions, too. Then again, more often than not, the quality of the information is as excellent as it is eclectic.

(Maybe it depends on whether or not you personally agree with it!) :p

Jeff White
October 18, 2008, 10:49 PM
Oh, 55 grain FMJ bullets will not blow up coming out of a 1-7" twist barrel, they just won't shoot very accurately past 100 meters.

What do you consider inaccurate? They were accurate enough to shoot 40 out of 40 on the RETS range from an M16A2 a few years back. Never had any complaints out to 300 meters with my R6920, Colt AR15A2 HBAR or my DM clone that's using a Diamaco C7 barrel all with 1/7 twist.

RockyMtnTactical
October 18, 2008, 10:56 PM
I like having both, but I prefer M193 in general.

http://www.ar15pro.net/2008/10/ammunition-part-1.html

Roadwild17
October 18, 2008, 11:01 PM
Well, I have a 1 in 9 twist on the barrel and my setup is only goiong to be out to about 250 yds. I think Im just going to to a half and half order.

Im sighted in at 50 yds and can reliable hit out to 250 on a standard B29 target ofhand using M193.

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