My Approach to a Semi-Auto Scout Rifle – Part 2, by Swampfox

(Continued from Part 1.  This concludes the article.)

Before the Test – Make Your Own Ballistics Gel

For ballistics testing at home, there are several options. At the time of my Mini-14 tests, I did not have any ClearBallistics gel or other commercial choices. If you want to do this a lot, perhaps buying a kit would be a good investment. I was short of time, so I whipped up some Knox gelatin. It is easy to do, but it takes a little time and patience.

If you are going to be doing a lot of testing, you will need more gelatin than you think. For a homemade 10% ordnance gel replica, you will be mixing 8 ounces of water for every 1 ounce of gelatin powder, or around 1 gallon of water per pound of gelatin mix. Do not get the gelatin packets, get the big tubs of it online in order to save money. For my testing, I made about 5 gallons of finished gelatin, which took 5 lbs of Knox gelatin powder. That stuff is not as cheap as it used to be, either. Again, if you are going to do a lot of testing, it could be better to buy a commercial kit.

Follow the instructions on the package, and mix all the gelatin powder with your water. This is a tedious process, as you want it to mix perfectly with no clumping. It also smells bad. Natural, unflavored gelatin is made from a mess of animal pieces, so I think it smells like rancid fat and decaying critter. This stuff must chill and hydrate overnight in your refrigerator before you can heat it, so make sure you eat your dinner leftovers beforehand. You will need to have enough space for buckets of gelatin, and your food might also take on the nasty scent.

The next morning, heat the gelatin on the stove, stirring constantly to make sure all the air bubbles are out. Pour the hot mixture into a mold, then place it back into the refrigerator. You can use pots or buckets as a mold, or get a rectangular ballistics gel mold for the purpose. ClearBallistics sells rectangular molds in different sizes. I used an old rectangular stainless steel cafeteria warming basin, which I obtained at a garage sale. You will want something that is 16 inches long or longer, and at least six inches wide and six inches high. Those are odd dimensions to find a container for. I’ve even known people who have made gelatin in buckets and then cut the blocks in half lengthwise.

If your gelatin process was successful, you will have an evenly translucent, tan/orange colored gelatin that is suitable for outdoor testing on cool days. On a hot day, this kind of gelatin will begin to reliquefy, so you will have to do your testing efficiently. This gelatin can also be reused, remolded, and frozen for later.

My Testing Process

Over the years, I have noticed that bullets behave differently during testing, depending on the test media. In the old days, the US Army even tested ammunition on live goats! Lacking a good quantity of disposable goats, I opted for water and gel tests, done outdoors on a folding utility table. I learned how to do the water tests from a wonderful website called “The Box O’ Truth.”  God bless the wonderful people who did all the testing on that website, as they have truly been an inspiration to my efforts. Check out the website, as the original tests used materials as varied as drywall, cement blocks, and even an old Buick.

My first tests were a simple stack of water jugs on a table. For testing purposes, 6 inches of water (1 jug) is roughly equivalent to 3 inches of ballistics gel or flesh. I took each variety of ammunition, and I shot three rounds into the water jugs. The issues quickly became clear. According to FBI data, self-defense rounds should penetrate approximately 12 inches in flesh. In the water, I was not getting anywhere close to the required depth:

Ammunition Type Velocity/Grains Water inches Gel equivalent Mass Retained
PNR Hornady Soft Point reload 3200 fps / 55 gr 12 inches 6 inches 75%
Hornady Critical Defense Rifle 3240 fps / 55 gr 12 inches 6 inches 50%
Winchester Ballistic Silvertip 3220 fps / 55 gr 6 inches 3 inches Small fragments
Hornady Varmint Express 3200 fps / 55 gr 6 inches 3 inches Small fragments

I noticed that when the bullets impacted the water jugs, they did not merely penetrate. While penetration was shallow, they burst the jugs completely open and even burst the jugs next to the jugs they hit. The impact was violent, and water sprayed everywhere. This phenomenon is known as “hydrostatic shock.” Because the .223 round has such high velocity, its hydrostatic shock is greater than its penetration. I concluded that the water jug test wasn’t very accurate, as the bullets were fragmenting more than they were penetrating. The Hornady Varmint Express round, as predicted, left only tiny fragments in the water and barely penetrated. I was very disappointed with the Winchester Ballistic Silvertip. In a larger round, both penetration and expansion are amazing. In the .223 round, it was equivalent to a varmint load. Not something I would use for defense or hunting larger game. I chose to move forward to the gel phase of the test, using the two better rounds – PNR Hornady soft point reloads and Hornady Critical Defense Rifle.

The results in my ballistics gel were better. Unfortunately, the Hornady Critical Defense Rifle ammunition did not meet the FBI penetration guidelines. The rounds created a large wound cavity with quite a bit of fragmentation, but stopped around 10.5 inches. The PNR reloads were the best of the ammunition I tested, mushrooming nicely and reaching 12.0 inches deep. Not too shabby, especially since they were the cheapest of all the rounds I tested.


My final test was a last-minute idea. I was roasting a ham for dinner that night, so I decided to shoot it before I cooked it. The ham was a bone-in portion, and I placed it on my testing table, still in its package. I had some water jugs remaining, so I assembled them behind the ham and put a round through it. The results were astonishing. The wound path through my ham was approximately 7.5 inches deep, and the bullet went through two water jugs afterward! That is a penetration total of approximately 13.5 inches, which is perfect. The damage to the ham was the surprise. I had aimed to go around the bone, but the bullet hit the bone and completely shattered it. Fragments of bone were everywhere in the meat, and the wound track was massive. The exit hole on the ham was the size of a silver dollar, and meat and bone fragments were blown out the exit hole and into the water jugs behind. I carefully picked out the remains of the bullet, as well as everything I could get from inside the ham before I cooked it. The bullet was mushroomed nicely to nearly a half-inch in diameter.

Overall, I was very satisfied with my test results. I obtained both a perfect penetration depth and expansion size, and I now have a round that is matched to my scout rifle platform. I will have no problem using it for medium game hunting or self-defense, and I can use the reduced penetration varmint rounds for smaller animals. The only limitation is that my shot placement on larger animals could potentially need greater precision than if I was using a .308 or 30-06, and if I went out West with this rifle, I would be undergunned for larger animals. But in my area and for my purposes, this works.

There are a couple of areas for future improvement. First, low-light capability. I am considering adding a laser to my rifle, to give me an aiming point in the dark. I do not like that option as well as a lighted reticle, but until what I want is produced, I must make do with what is on the market. Currently, I have a small flashlight mounted to the Ultimak rail for those unexpected close-range encounters at night. I have already used it to dispatch a couple of unwanted armadillos. Aside from the low-light issues, I may add a different kind of sling later. Cooper’s concept calls for a Ching sling, which I have never used. I have my old web strap still on there, which I have had for years. I have my eye on a Galco Rifle-Mann sling that I may purchase eventually. It is described as an improvement on the Ching sling, which could help shooting from an unsupported standing position.

If you want to create your own scout rifle, you should customize it to your style and preferences. While some gun writers may disagree, I believe that Jeff Cooper’s concept is a starting point, rather than gospel. If light weight is important, then you could even make a scout rifle out of an AR-15 with a light barrel. The new KeyMod and MLOK style metal handguards make secure forward mounting possible, even on a free-floating- style AR-15 barrel.

Of course, traditional bolt action Mauser rifles and the Remington 700 platform have been used, and even the trusty SKS rifle has been made into a scout platform, although it is rather heavy for the purpose. If you have the money, Ruger makes a nice bolt-action scout rifle in several different calibers, which roughly fits Jeff Cooper’s concept straight out of the box.

To me, building or modifying a rifle is part of the American dream. Check out the possibilities, then have it your way!