62gr M855 or 55gr M193: Must choose ONE or THE OTHER for 16" bbl 1:7 twist

[vicious_cb]

If you read those old DARPA reports from Vietnam, the most lethal terminal effects were achieved with a 55 grain projectile in a 1:12 (or was it 1:14?) twist barrel. This with the old Model 601's.

Twist rate has nothing to do with the terminal ballistics of the round. 1/7, 1/9, 1/12, 1/14 are all identical in wounding capability.

M193 leaves a hell of a wound channel. Google it

Until it doesn't, both M855 and M193 have consistency issues likely due to fleet yaw where they had variable performance, more documentation occurring with M855 green tip but it happened with M193 as well:

“In 1980, I treated a soldier shot accidentally with an M16 M193 bullet from a distance of about ten feet. The bullet entered his left thigh and traveled obliquely upward. It exited after passing through about 11 inches of muscle. The man walked in to my clinic with no limp whatsoever: the entrance and exit holes were about 4 mm across, and punctate. X-ray films showed intact bones, no bullet fragments, and no evidence of significant tissue disruption caused by the bullet’s temporary cavity. The bullet path passed well lateral to the femoral vessels. He was back on duty in a few days. Devastating? Hardly. The wound profile of the M193 bullet (page 29 of the Emergency War Surgery—NATO Handbook, GPO, Washington, D.C., 1988) shows that most often the bullet travels about five inches through flesh before beginning significant yaw. But about 15% of the time, it travels much farther than that before yawing—in which case it causes even milder wounds, if it missed bones, guts, lung, and major blood vessels. In my experience and research, at least as many M16 users in Vietnam concluded that it produced unacceptably minimal, rather than “massive”, wounds. After viewing the wound profile, recall that the Vietnamese were small people, and generally very slim. Many M16 bullets passed through their torsos traveling mostly point forward, and caused minimal damage. Most shots piercing an extremity, even in the heavier-built Americans, unless they hit bone, caused no more damage than a 22 caliber rimfire bullet.”

Fackler, ML: “Literature Review”. Wound Ballistics Review; 5(2):40, Fall 2001

[SteyrAUG]

For me 55gr is range / training ammo and 62 gr is fighting ammo.

I could train with 62 gr, and have, but it's an expensive thing to do.

I could use 55 gr in a defensive situation, and have, but it's not ideal.

The only thing I don't do is 62 gr. down the old 1:12 twist vintage Colts I have.

[yoni]

My old 1 in 12 twist Colt commandos with 55 grain did a very good job. It isn't dropping 120 mm round directly on the guy. But I did not have any real complaints with it.

[C-grunt]

I've seen a lot of people shot with 55 grain ball. The majority is probably even cheap steel cased. I cant recall ever seeing it cause a wound similar to a 22 rimfire. Even through extremities where bones weren't hit, it creates a significant wound.

[Wake27]

I don’t think many people argue that 193 or 855 are truly bad, at the end of the day, they tend to by flying and everyone has seen a few examples of significant damage both have caused.

But it goes back to similar other shooting topics - is it consistent and repeatable? That seems to be debated, if not proven to be a no.

And even easier to answer, is there significantly better that doesn’t have major trade offs? Yes, without a doubt.

Blast 55gr junk all day. But most people on here can probably afford to buy at least 60 rounds of a significantly better performing round for actual defensive use.


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[lysander]

If you read those old DARPA reports from Vietnam, the most lethal terminal effects were achieved with a 55 grain projectile in a 1:12 (or was it 1:14?) twist barrel. This with the old Model 601's.

Some of the best fiction I ever read . . .

"At a distance of . . . 15 meters, one (Vietnamese) Ranger fired an AR-15 full automatic hitting one VC with 3 rounds fired with the first burst. One round in the head-took it completely off . . ."

"Back wound . . . which caused the thoracic cavity to explode . . ."

"Five VC were hit . . . the fifth was essentially a flesh wound. The AR made it a fatal wound." (No further information on this incident is given, like where the actual round hit the VC.)

1000 rifles and half a million rounds of ammunition delivered for field testing, but less than a dozen actual combat reports, and all are anecdotal.



The annoying thing is the initial testing that showed a .22 caliber bullet to be so good was done on a 52 gr, steel core jacketed bullet going 3,956 fps with a 1-in-9.68 twist. The steel core makes the bullet fairly long, about one inch, and the high velocity make the terminal ballistics very different from a 55 gr lead core bullet plodding along at 3250 fps.

[lysander]

M193 leaves a hell of a wound channel. Google it

The earth is flat. Google it.

The moon landings were fake. Google it.

MI5 killed Princess Diana. Google it.

That's not the best form of evidence to prove a fact . . . .

[markm]

You forgot "the elections weren't rigged" Google it!!

[Disciple]

The annoying thing is the initial testing that showed a .22 caliber bullet to be so good was done on a 52 gr, steel core jacketed bullet going 3,956 fps with a 1-in-9.68 twist. The steel core makes the bullet fairly long, about one inch, and the high velocity make the terminal ballistics very different from a 55 gr lead core bullet plodding along at 3250 fps.

What did that cartridge look like?

[lysander]

What did that cartridge look like?

A .243 Winchester necked down to .224.