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Old December 29, 1999, 05:26 PM   #1
4V50 Gary
Join Date: November 2, 1998
Location: Colorado
Posts: 20,158
Since not all of us are members of the NRA nor do all members get the American Rifleman, I reprint this letter (American Rifleman, Jan 2000, p. 4) from Dr. Marvin Fackler:

"The article 'FN's FiveseveN System (No.v/Dec. 1999 p.40) seriously misrepresents the wounding capacity of the 31-gr. P90 bullet. Claiming it "produces a wound cavity that is similar to that of the 5.56 mm NATO ammunition is an absurd exaggeration. The 31-gr. P90 bullet has only half the weight of the M16A2 bullet - and its velocity is about 1000 f.p.s. less. (The reference was intended to convey that it is an FMJ design, not that it has equal energy and wounding characteristics to the 5.56x45 mm cartridge. - The Eds).

The amount of tissue disruption propduced by the P90 bullet is less than one-third of that produced by a well-designed expanding 9x19mm handgun bullet. And the P90 produces a temporary cavity of only about 8cm diameter - smaller than that of an expanding 9mm handgun bullet. Most of the P90's bullet's wounding potential is wasted in producing a temporary cavity that is too small to be a reliable wounding mechanism. The P90 bullet doesn't even come close to matching the wounding capacity of a well-designed, expanding 9mm handgun bullet.

The light recoil of the P90 should hardly come as a surprise: The momentum and kinetic energy of its bullets are only about half that of the .22 Hornet bullet. The P90 bullet's wounding potential is about equal to that of the .22 WMR bullet. The laws of physics cannot be denied - minimal recoil is inconsistent with maximal tissue disruption.

For the military, where any wound is often all that is required to cause an enemy soldier to leave the battlefield, perhaps this tiny P90 bullet is OK. Law enforcement officers are often faced with armed violent criminals at close range. In that scenario, a bullet capable of disrupting a significant amount of tissue is needed: One must incapacitate a criminal, a minor wound will not suffice. By no stretch of the imagination is the P90 bullet adequate for that task.

References for further reading in the Wound Ballistics Review are: Vol. 3, No. 3, 1998 (pp. 36-37) 'Corrections on the Wound Ballistics of the current FN P90 bullet'; Vol. 3, No. 1, 1997 (pp. 44-45) "more on the bizarre FN P90'; and Vol. 1., No. 1, 1991 (p. 46) 'Description of the first generation P90.' These may be obtained from the IWBA by calling (310) 640-6065, or its website at

Marvin L. Fackler, MD, FACS,
President, Int'l Wound Ballistics Ass'n.

The 5.7 was designed primarily for a military and special operations role, not as a duty cartridge for typical law enforcement officers - The Eds."

So there you have it from the pages of the American Rifleman.

BTW, I'd stay with Melvin Johnson's 5.7 mm Spitfire conversion of the M1 Carbine before I'd go with the FN 5.7. Less work that way (check out the thread I started in the Rifle forum on this matter).

Vigilantibus et non dormientibus jura subveniunt

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