VIRGEL: Estimating Bullet Penetration & Permanent Cavity Wound Mass

[pettypace]

VIRGEL is a free online “calculator” for estimating the two critical wounding components for handgun ammunition: bullet penetration and permanent cavity wound mass. Here’s a link to VIRGEL with data pre-loaded for a .38 target wadcutter fired from a snubby:

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(I just had a phone conversation with Charles Schwartz who feels that VIRGEL violates his intellectual property rights. To keep the Cast Boolit community out of the fray, I've decided to delete the link above.)

The name “VIRGEL” stands for “VIRGEL Isn’t Real GELatin.” Compared to real ballistic gelatin, VIRGEL has its limitations: It can’t handle high velocity rifle bullets or predict the penetration of tumbling bullets, or predict bullet expansion. (For VIRGEL, expanded bullet diameter is an input – not an output.) On the other hand, compared to real gelatin, VIRGEL is cheaper, more convenient, “infinitely” re-usable, and won’t go bad if left in the back of the Volvo for a month. But the truth is that there’s really no comparison between VIRGEL and real ballistic gelatin. VIRGEL is a heuristic tool and ballistic gelatin is a measurement tool. They don’t serve the same purpose.

VIRGEL is based on the mathematical modeling in Duncan MacPherson’s book Bullet Penetration. Penetration estimates are “tuned” to data interpolated from MacPherson’s penetration graphs and, in “Self-Defense” mode, VIRGEL calculates wound mass following MacPherson’s “wound trauma incapacitation” model --ignoring tissue damage from the last 3” of penetration (where low velocity minimizes damage) and ignoring damage from penetration beyond 15” (because the bullet has likely already exited the target). In “Big Game” mode, wound mass is calculated for all but the last 3” of the full penetration path.

To get an idea of what VIRGEL can do, you might try using it to arrange this list in order of increasing wound mass:

A) a 148 grain .38 Special “target” wadcutter fired from a 2” snubby at 650 ft/s
B) a 230 grain .45 ACP FMJ fired from a 1911 Colt at 850 ft/s
C) a 158 grain hard-cast .38 SWC fired from a 2” snubby at 750 ft/s
D) a 110 grain JHP fired from a 2” snubby at 980 ft/s and mushroomed to 0.60”
E) a 158 grain .38 Special “FBI Load” fired from a 4” revolver at 880 ft/s and mushroomed to 0.59”
F) a 437 grain 12 gauge rifled slug fired at 1500 ft/s and mushroomed to 1.10”
G) a 37 grain .22 LR HP fired from a rifle at 1272 ft/s and mushroomed to 0.38”
H) a Federal .410 handgun shot shell with four 70 grain, 0.36” round balls at 850 ft/s
I) a 200 grain, soft-lead 44-40 fired at 900 ft/s and mushroomed to 0.60”
J) a 100 grain .32 ACP fired at 940 ft/s and mushroomed to 0.40”

[The Schwartz]

Thank you, pettypace.

I'll let the owner of castboolits.gunloads.com know that he can disregard the contact message that I sent earlier.

Let's put this matter behind us.

I do enjoy your posts, pettypace. They are insightful, intelligently composed, and tremendously entertaining to read.

I also encourage everyone to rely upon the riches that we are blessed with—that is, the massive amount of published material in the fascinating field of terminal ballistics—to educate themselves. So long as it is done with due regard for the rights of those authors' and researchers' who've created these scientific treasures, I am all for the opportunity they provide for everyone to study the field.

Kindest regards to all!

[Minerat]

Thanks you gentlemen for working this out in a manner that satisfied you both and in the spirit of the Cast Boolits brotherhood.

Bravo,

Steve

[The Schwartz]

Thanks you gentlemen for working this out in a manner that satisfied you both and in the spirit of the Cast Boolits brotherhood.

Bravo,

Steve

Nothin' but adults in the room here, Steve, which makes the Castboolits forum a great place to be!

—Chuck