Fragmentation ?'s

[Tim-G19]

I cant seem to find a good link talking about velocity and what bullets fragment.

I understand you rely on the mushroom effect of handgun/slower rounds to cause trauma.

But will normal FMJ .223 or 5.56 ammo fragment within tissue?

at what velocity do the light rounds like 5.56 break up?

and if the military relies on this, (I understand they are limited on what bullet style they can use.) Why do so many people use hollow point .223/5.56 such as TAP for self defense. Do these bullets not fragment.

As with all spitzer shaped projectiles it is prone to yaw in soft tissue. However, at impact velocities above roughly 820 m/s (2,700 ft/s), it may yaw and then fragment at the cannelure (the groove around the cylinder of the bullet). The fragments can disperse through the flesh causing much more internal injury. Fragmentation, if and when it occurs, seems to impart much greater damage to tissue than bullet dimensions and velocities would suggest.

is this something special about the steel core round? or are regular 55gr FMJ's going to do this?


thanks for any links or info sent this way.

[RMTactical]

Here is a good link

http://www.ammo-oracle.com/body.htm

Just to answer some of your questions quickly though, it depends on the bullet. Many 55gr FMJ's will fragment, but not all. The smallest variable can make a bullet more or less destructive.

Many bullets that won't fragment, will still tumble once they impact soft tissue. If the speed is great enough, and depending on the construction of the bullet and things it may impact in the soft tissue such as bone can influence it as well.

The military 55gr M193 bullet as well as the M855 62gr bullet will usually fragment violently and reliably as long as it is going 2700fps or faster upon impact. Lesser fragmentation and less reliable to fragment at speeds as low as 2500fps.

Many other bullets will fragment too...

Here is some more stuff about good defensive loads in this caliber that you may find interesting.

http://www.ar15.com/content/page.html?id=185

First, a few points:

5.56 vs. .223 loads. A "5.56" load means that the round is loaded to "military" pressures, which exceeds SAAMI's safe rating, and generally means from 120 fps (75-77gr bullets) to 200 fps (55gr bullets) additional muzzle velocity. AR-based rifles with "5.56" or Wylde chambers can fire this ammo safely. More muzzle velocity means a longer fragmentation range, so 5.56 loads are more desirable. Having said that, you are almost always better off using a better-performing bullet in a .223 load than a lesser-performing bullet in a 5.56 load.

Generally, Open-Tip Match (OTM) bullets, also called Jacketed "Hollow-Point - Boat-Tail, Match" (JHP-BT Match) or Boat-Tail Hollow-Point, Match (BTHP Match) bullets, are the most reliable performers, as the consistancy in construction required for match accuracy also results in consistant terminal ballistic performance.


Okay, from best to worst:

1. Loads using the Nosler 77gr or Hornady 75gr OTM bullet. While these bullets may be slightly less accurate *in some rifles* than the Sierra MK, they offer better wounding capability. These bullets maximize terminal ballistic performance AND they extend fragmentation range over other loads, and even provide *some* fragmentation range from 10" barrels. These bullets require 1:8 or tighter twist barrels, though they may work in SOME 1:9 barrels.

- Hornady 75gr TAP (5.56 load)
- Hornady 75gr TAP or TAP-PD (.223 load)
- Black Hills loads with 75gr Hornady (.223)
- (no known factory load using the Nosler bullet)

2. Loads using the Sierra 77gr MK. Like all MK bullets, this one doesn't start to yaw until it passes through several inches of flesh, resulting in a longer "neck" area of the wound profile, and thus being rated slightly lower than the Nosler or Hornady bullets.

- Black Hills Mk262 Mod1 (5.56, cosmetic seconds are available)
- Black Hills 77gr Sierra loads (.223)
- Federal 77gr Sierra (.223)


77grain MatchKing OTM in calibrated ballistic gelatin. Note the long "neck" before fragmentation begins.


3. Loads using the 68gr Hornady OTM. Note: barrel length needs to be 14.5" or longer; these will not have enough velocity to fragment from a 10" barrel and only a couple of yards from an 11.5" barrel. 1:9 or faster twist required.

- Hornady 68gr Match (.223)
- Black Hills 68gr Hornady (.223)

4. Loads using the 69gr Sierra MK. Note: barrel length needs to be 14.5" or longer; these will not have enough velocity to fragment from a 10" barrel and only a couple of yards from an 11.5" barrel. 1:9 or faster twist required.

- Federal 69gr Sierra (.223)
- Black Hills 69gr Sierra (.223)

5. Loads using Trophy-Bonded Bear Claw bullets. The 62gr performs a bit better than the 55gr, but the 62gr bullet is ONLY available in the LEO-only Federal Tactical line. As a bonded-core bullet, these are excellent in situations with an intermediate barrier, and are the #1 performers when having to shoot through glass. Note: these soft-point bullets have an exposed lead tip and cannot be rechambered more than a few times. May not feed reliably in some rifles.

Federal Tactical 62gr TBBC (.223)
Federal Tactical 55gr TBBC (.223)
Federal Premium 55gr TBBC (.223)


6. Loads using the Winchester 64gr PowerPoint bullet. Note: these soft-point bullets have an exposed lead tip and cannot be rechambered more than a few times. May not feed reliably in some rifles. 1:10 or faster twist required.

- Winchester Supreme PowerPoint Plus (.223)
- Winchester Super-X PowerPoint (.223)


7. M193-class ammo, 55gr FMJ-BT bullet. True M193 ammo will be sealed at the bullet and primer, will have a crimped primer and bullet, and is a 5.56 pressure loading. 1:12 or faster twist required.

- Lake City M193 (genuine surplus M193; no longer available)
- Federal XM193 (seconds) or XM193PD (thirds)
- Winchester Q3131 (seconds)
- Winchester Q3131A (manufactured by IMI)
- IMI M193
- PMC, '98 and earlier
- South African M1Ax in battlepacks

8. M855-class ammo, 62gr FMJ-BT bullet with mild steel penetrator in the nose. True M193 ammo will be sealed at the bullet and primer, will have a crimped primer and bullet, and is a 5.56 pressure loading. 1:10 or faster twist required.

- Lake City M855 (genuine surplus M855; no longer available)
- Winchester M855 (genuine surplus M855; no longer available)
- Federal XM855 (seconds) or XM855PD (thirds)
- Canadian IVI (genuine surplus M855; no longer available)
- British SS-109


This list should give you an idea of what is preferred, and in what order. Obviously, many of the loads at the top are quite a bit more expensive than the loads further down (though the TBBC loads are by far the most expensive), but if you're looking just at performance, then this should be your guideline.

I might not have gotten every load out there, but you should be able figure it out if there's a similar load that I didn't mention.

ETA:

Loads To Avoid

Anything loaded with a varmint bullet; all varmint bullets in this caliber will underpenetrate from all guns. This means NO VMax bullets (including TAP loads), NO Nosler/Combined Technologies "Ballistic Tip" bullets, and so on. Varmint bullets were designed for animals no larger than 60 lbs., with the lighter bullets being designed for even smaller animals. They are NOT combat bullets, regardless of marketing to the contrary.

Any frangible bullet load. Frangible bullets are designed for short-range training, where shooting standard bullets at reactive steel targets would be (more of) a safety hazard. Usually, they are made from powdered lead or tungsten alloy inside a gilding metal jacket. They are designed to disintegrate when striking steel plates, but they are NOT designed to (nor do they accidentally) fragment in flesh.

"Armor Piercing" bullets. It is incredibly unlikely that anyone outside of the military will be able to put their hands on a single round of TRUE AP ammo in 5.56, as M995 AP ammo is a speciality item that is rarely issued to anyone but SOCOM troops, and then only on SAW belts, and only when specially requested for a specific mission. It is very expensive and in short supply, and it was designed primarily to disable equipment, NOT for wounding. Since the bullet will not fragment, it is a poor performer with regards to wound profile. This would hold true for any all-steel core or solid copper bullet as well.