Gallon Milk Jug to Ballistic Gelatin Conversion?

[.455_Hunter]

Greetings!

Does anybody know a ROUGH conversion factor for penetration of water-filled milk jugs to ballistic gelatin? Say a bullet was recovered inside a fourth jug, its gelatin penetration would be approximately XX to XX inches.

Thanks!

 

[o Unforgiven o]

That is a very ambiguous question, did you have a specific caliber in mind? Im assuming you want a rough estimate for handguns given the sub-forum but a 5.7 is a lot different than a .45.

 

[.455_Hunter]

Let's say in the the traditional handgun realm of 600 to 1200 fps.

 

[Double Naught Spy]

Part of the problem is that not all gallon jugs are created equally. The thickness of the walls will vary between makers and location on the wall itself.

Another problem is that each jug gives you two membrane layers to be penetrated. Unlike gel that is uniform (or should be) in consistency, the jug walls result in alternating consistenices where the bullet passes throught the first wall, water, second wall, air gap, third wall, water, fourth wall, air gap, etc. etc.

Of course where things get even funnier is that calibrated ballistic gel is supposed to simulate soft tissue. Now with the water jugs, you are trying to simulate the simulant.

 

[BushyGuy]

my opinion is 3-1 gallon jugs filled with water are equivilent to 12 inches of ballastic gelatin. i did tests on water jugs and compared them to the tests that were done by people with ballastic gelatin and it was almost equivilent .

 

[o Unforgiven o]

Let's say in the the traditional handgun realm of 600 to 1200 fps.

Again a 1200fps 9mm will behave much differently than a 900fps .45. Then it brings up HP? Or maybe FMJ? Lead wadcutter? Are the jugs filled to top or is there room for water to expand? To many variables here and im not sure there would even be a ROUGH correlation between tests.

I think you meant rough as in unfinished plywood, but instead your gonna get the whole tree.

 

[0VERKILL]

I read where someone had theorized that since ballistics gel was 90% water, multiplying your penetration results by 0.9 would give you a rough estimate. I don't trust it though.
I suppose water jugs would be a good way to compare bullets/loads to each other as long as you used the same brang of jugs.

 

[chupacabrah]

all I know is that one 0.5 gal OJ carton, one gal Milk jug, and 1 medium sized pumpkin stopped a WWB .45ACP JHP

 

[OFT]

With hard water or soft water?

 

[.455_Hunter]

Thanks to Bushyguy and the other commenters!

My opinion is 3-1 gallon jugs filled with water are equivalent to 12 inches of ballistic gelatin

Looking at Brassfetcher.com and Steve's Pages Terminal Ballistics, I think that value seems about right:

A 9mm 124 gr Golden Saber +P fired at 1172 fps penetrated into and stopped inside the fourth water jug. (http://stevespages.com/page8f9mmluger.html)

A 9mm 124 gr Golden Saber +P fired at 1114 fps penetrated 12.8 inches of calibrated gelatin. (http://brassfetcher.com/index_files/Page1834.htm)

Full penetration of three jugs seems to indicate a rough penetration of 12 inches of gelatin.

I know there are too many variables for this to be an exact science- that's OK!

 

[Shawn Dodson]

A Simple Method for Testing Bullets with Your Guns

A quick and easy method to determine bullet or shotshell performance out of any handgun or shotgun is to gather several (and we mean several -- about 30) cardboard half-gallon milk cartons (plastic won't do).

Fill them full of water, line them up side-by-side three abreast, in three rows of 10 (each carton should be in contact with its neighbor). Back-up several feet and shoot a bullet from your handgun into the center row of cartons.

Count the number of water filled cartons the bullet penetrated, including the carton where the bullet came to rest. Multiply the number of cartons times 2.5 to determine penetration depth in inches. This will give you a SWAG (scientific wild-ass gauge) of how your gun/cartridge combination will perform in soft tissue (both bullet expansion and penetration).

The data obtained and averaged from three test shots should give you a fairly accurate SWAG. Remember to observe all safety rules when handling your firearm.

http://www.firearmstactical.com/briefs3.htm

Also:

"Penetration in rows of water-filled, 2-quart (1.89 liter) cartons is approximately 1.5 times that which would occur in 10% 4 degrees C gelatin. Since a U.S. 2-qt. carton is 3.75 inches (9.525 cm) wide and 3.75/1.5 = 2.5, one simply multiples the number of the carton in the row from which a test bullet was recovered by 2.5 to determine approximate gelatin penetration in inches or by 6.35 for the reading in centimeter. For example, a shot recovered from carton #6 would correspond to a gelatin penetration depth of approximately 15 inches (38.1 cm). (Cotey, Gus Jr.:"Number 1 Buckshot, the Number 1 Choice." Wound Ballistics Review, 2(4): p. 11; 1996.)

http://www.firearmstactical.com/briefs12.htm

 

[cougar1717]

cos 6A*(C - [sqrt(B^2-4AC)/2A])

Where,
A= number of plastic jugs gone through
B= fps of bullet at muzzle
C= bullet weight in grains

Doesn't everyone know that conversion?

 

[481]

I've seen numbers from 1.80 to 2.50 for the penetration conversion ratio.

When I am testing in water (I use gallon freezer bags filled with water lined up one behind the other) and I want to make sure that I capture the test bullet, I use a conversion factor of 3.00. I've never lost a bullet to overpenetration.

Might wanna have a look at Duncan MacPherson's book, "Bullet Penetration" for further insight into the topic, too.

 

[Ruger GP100 fan]

Why not make your gelatin mold in a tube sold for forming cement columns or foundations. They sell them at all home improvement stores. When the mold sets you can just cut away the cardboard tube.

 

[Vern Humphrey]

The conversion factor for a Fackler Box is to divide by 1.8.

The Fackler Box is not the same thing as a row of milk jugs. The Fackler Box is an open-ended trough with gallon Zip Lock bags filled with water.

 

[fastbolt]

The Fackler Box is not the same thing as a row of milk jugs. The Fackler Box is an open-ended trough with gallon Zip Lock bags filled with water.

An excellent observation. This is a point seemingly missed by some folks who like to invest a lot of time & money in "backyard testing".

Penetrating layers of hard plastic bottles is not the same as properly conducted gel block/barrier or Fackler Box testing.

 

[481]

The Fackler Box is not the same thing as a row of milk jugs.

I never said that it was.