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Posted: 5/19/2003 8:00:41 AM EDT
Anyone know where I can find a good "home-made" ballistic gelatin recipe or similar? I'd like to do some of my own frag. experiments on the 75gr. and 77gr. bullets. If no one knows of a recipe..can it be purchased commercially? Thanks in advance..
Link Posted: 5/19/2003 10:31:17 AM EDT
In the past I have purchased Kind & Knox Gelatin from a local grocery store. I believe that 10% by weight added to 90% water will give you a usable product. If I remember correctly you should not use boiling water(just hot water) because it effects the gelatin. Once you are done pour the product into square paper milk containers and refrigerate. In a few hours you will have nice uniform blocks to test you favorite OTM or JHP's on. HTH
Link Posted: 5/19/2003 10:45:55 AM EDT
Why not IM or e-mail the folks who do tests for the AR-15 ammo-faq, Tatayana or brouhaha, and ask them how they make theirs...... bet they can help ya get it right the first time. As I recall, it's technical and ya should always test it using a .177 pellet rifle at some designated fps at so many feet, if ya want your results to be taken seriously.....it ain't like making jello. [;)] Mike
Link Posted: 5/19/2003 11:28:34 AM EDT
http://www.vyse.com/gelatin_for_ballistic_testing.htm That's from the manufacturer of the gelatin. I don't know where you can get it; you'd have to email the company for the info. They don't provide links to merchants which stock the stuff.
Link Posted: 5/19/2003 11:36:58 AM EDT
FWIW, I've always heard that it's a good idea to add a touch of bleach if you plan on keeping in on hand for any amount of time. This stuff is essentially the base for what is used in petri dishes you know :-) Ed
Link Posted: 5/19/2003 1:01:35 PM EDT
Here's the more complex way... A SIMPLIFIED 10% ORDNANCE GELATIN PREPARATION AND TEST PROCEDURE Materials and equipment required: Kind & Knox gelatin powder (1 kilogram) Triple beam balance Stainless steel mixing bowl (3 quart) 5 gallon plastic paint bucket Graduated pitcher (3 liter) or measuring cup (1 liter) Thermometer (capable of measuring fluid temperature of 130° F ± 10° F) 9 liters hot tap water (130° F ± 10° F) Electric Drill Paint Stirrer (w/ plastic propeller-type blades) 12cc hypodermic syringe Aquarium air hose (6 inches long) Propionic acid Large spoon Silicone spray mold release Gelatin mold (FBI size: 6"W x 7"H x 16"L) Refrigerator (capable of maintaining approximately 39° F) Thermometer (capable of measuring air temperature of 39° F ± 10° F) Kitchen size (13 gallon) plastic garbage can bags Ice chest (if necessary) Gelatin block test stand Pneumatic (pump-up) air rifle capable of shooting steel BBs Chronograph Ruler, metric (45 - 60 centimeters) Bullet Penetration (book) by Duncan MacPherson Dial caliper Denim cloth (14.5 - 16 ounce) Procedure: Using triple beam balance, measure 1 kilogram ordnance gelatin powder. Pour pre-measured gelatin powder into 3 quart stainless steel mixing bowl. Place bowl aside, out of immediate work area. Note: If balance does not have capacity to measure 1000 grams, measure two 500 gram portions or four 250 gram portions. If gelatin powder is scooped into a container and the container is placed on the balance, be sure to take the container's weight into consideration or your gelatin powder weight will be incorrect. Weigh the container first and add the container's weight to the desired weight of the gelatin powder to be measured. If you're measuring two 500 gram portions of gelatin powder and the container weighs 75 grams, set the balance to measure 575 grams. Using graduated pitcher/measuring cup, measure 6 liters hot tap water (130° F ± 10° F) into 5 gallon plastic bucket. Add 1 kilogram pre-measured gelatin powder to hot tap water while slowly mixing with paint stirrer attached to electric drill. Pour and mix approximately 1/3 of the pre-measured gelatin powder at a time, ensuring all gelatin powder is thoroughly mixed before adding more. (If you add the gelatin powder while mixing, be careful that the airflow produced by the electric drill doesn't blow your ordnance gelatin powder all over your work area. We found it best to pour about 1/3 of the powder directly into the water, and then turn-on the drill to mix it thoroughly before stopping to add more powder.) Exercise care to prevent entrapment of air in gelatin solution. After 1 kilogram gelatin powder has been thoroughly mixed into 6 liters hot tap water, use syringe to measure and add 5 milliliters propionic acid to gelatin solution to inhibit mold growth. (Propionic acid is not necessary if you intend to shoot the gelatin block within a week after preparation and you intend to dispose of the gelatin block immediately after testing.) Add 3 liters hot tap water (130° F ± 10° F) to gelatin solution. Slowly mix gelatin solution for 3 - 5 minutes, ensuring all gelatin powder is dissolved. Exercise care to prevent entrapment of air in gelatin solution. Use large spoon to scoop off foam from surface of gelatin solution. Dispose of foam in sink while running warm tap water. Spray gelatin block mold with silicone spray mold release for ease of gelatin block removal. (Ensure gelatin mold is clean and dry. Small particles of dried gelatin solution adhering to internal surfaces of mold can produce gouges in gelatin block when it is removed from the mold.) Carefully pour gelatin solution into mold. Let stand at room temperature for 4 hours to hydrate. Tent mold with aluminum foil to protect it from airborne contaminants. Place filled mold, uncovered, in refrigerator at 39° F. Wait at least 24 hours before attempting to remove gelatin block from mold. When removing gelatin block from mold, pour a small amount of ice cold water between mold and gelatin to ease removal. After gelatin block is extracted from mold, blot water from block using paper towels. Wrap gelatin block in plastic bag. Return to refrigerator at 39° F. After gelatin block is removed from mold, wait at least 24 hours before shooting block to allow gelatin temperature to stabilize. Gelatin is ready to shoot when 48 hours old. Larger gelatin blocks may require additional time to properly cure before use. Use ice chest (add no ice) as an insulated container to transport ordnance gelatin to shooting range. Use thermometer inside ice chest to monitor temperature. Remove gelatin block from ice chest, unwrap it, and place it on test stand. Position chronograph sensors (skyscreens/photoelectric screens) directly in front of gelatin block to measure projectile impact velocity. Note: Time is of essence. Depending on ambient air temperature, the gelatin block will begin to warm as soon as you remove it from the ice chest. It's best to test in an environment in which the ambient air temperature is 65° F or cooler. A good rule of thumb to follow is to complete your testing within 20 minutes after removing the gelatin block from the ice chest. If you believe a gelatin block may have warmed, verify it meets calibration standards. Calibrate gelatin block by shooting a steel BB into it at a velocity of 590 feet per second ± 30 fps. The BB should penetrate 8.5 centimeters. (Note: If BB velocity is not exactly 590 fps, refer to Bullet Penetration, Figure 5-2 Velocity Variation Correction to Measured BB Penetration Depth [p. 84] to correct BB penetration depth.) Record calibration data. Note: We use a calibration standard of 7.7 - 9.4cm BB penetration (corrected) at 590 fps velocity. This provides a calibration tolerance of plus or minus 10 percent. As long as the BB achieves this range of penetration/corrected penetration, we consider the data to be valid as measured. If the BB does not achieve this range of penetration/corrected penetration, bullet penetration data can be corrected using the formulae from Duncan MacPherson's article A Simplified Penetration Depth Correction for Data Taken in Non-standard Gelatin. If two or more gelatin blocks are going to be lined-up end-to-end to capture the entire wound path of the bullet under test, each and every gelatin block must be calibrated in accordance with step 17. After calibrating, the gelatin block(s) is(are) ready for terminal ballistics testing. Depending on the cartridge being tested, more than one bullet can be shot into the block(s). Carefully plan each shot to avoid overlap of previous temporary cavities/wound paths, and to ensure the bullet will not exit the sides or top of the block. It's best to measure penetration depth after each shot is completed. This practice minimizes loss of data if one bullet collides with another in the gelatin block. After penetration depth is measured, the bullets can be recovered at a later time to measure expansion diameter using dial caliper. If denim cloth is used to test bullet expansion performance, cut a 4 feet long, 6 inch wide strip of cloth. Fold the cloth strip lengthwise twice. This produces a cloth test fixture that's 1 foot long and four layers thick. Place the cloth loosely against the gelatin block, half on top of the block, half hanging over the front of the gelatin block.
Link Posted: 5/19/2003 4:28:16 PM EDT
[Last Edit: 5/19/2003 5:05:49 PM EDT by jaeger_1969]
WOW! That's alot more complicated than just making jello...Thanks to all so far who've answered my questions. I'll have to mull over the logistics of this a little more carefully, but still should be great. I'll round up the supplies this week and cook it down on Saturday. If I can make spec blocks, I'll test on Sunday? I'll attempt to get good confirming results with what tatjana(sp?)and brouhaha((sp?) have posted. Anyone have one of those spare evil 100gr. slugs they'd like to see tested?? [frag] On second thought it will probaly be a least Monday to comply with the 48 hr. requirement listed above...Thanks All.
Link Posted: 5/19/2003 5:03:55 PM EDT
Anyone have one of those spare evil 100gr. slugs they'd like to see tested?? [frag]
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Nah. But I wouldn't mind seeing some "cheap" ammo tested to see how the plinking stuff does. Like the Wold 55gr HP, or the Silver Bear 62gr HP. Did you find a place that sells the gelatin ?
Link Posted: 5/19/2003 5:18:38 PM EDT
Haven't been able to find gelatin comercially. As far as the M193 and M855 type ammo, its covered in the FAQ real well. If you haven't read it, I highly recommend it. I will say that my good friend and general all around ballistics genius "Rapidfire" says that the basically steel slug of the Wolf and Silver Bear will not hardly fragment at all...although I wasn't a witness to the exceution with his tests on wolf and silver bear I trust his informal tests. (ie..probably not "in-spec" gelatin).
Link Posted: 5/19/2003 7:02:51 PM EDT
Ok you need Nitro-glycol, Guncotton (IMR), Potassium Nitrate and Flour (baking). Opps sorry wrong gelatin. MM Ain't the internet grand!
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