How do you test bullets for expansion and penetration? While most will probably agree that calibrated 10% ballistic gelatin is the best media for seeing what bullets will probably do in tissue, most of us do not have the finances to shoot it in a controlled atmosphere within a specific temperature range for repeatable results.  I know I don't and I cannot afford the cost of the gelatin itself, either.


For these reasons, I perform less "scientific" tests and use two media and look at the results from both.  They are water and "wet pack."  The former is shot in 2 liter plastic pop bottles that I fill before going to the range. I'd much prefer to use baggies and set up a "Fackler Box" as do some others, but have no access to the water required to do this for more than but a few shots per visit.  Therefore, I use the pop bottles.  The wet pack is merely newsprint that has been soaked for 24 hours and allowed to drain about a half-hour before shooting.


I take about 12" of dry newsprint that's been folded once and tie a string around each end with about 1" of slack in it.  I then tie a string around it length-wise with the same amount of slack.  Be sure the colored, slick advertising paper has been removed.  The slack is there as the newsprint will swell quite a bit.  The stack will go to about 14" or so when supersaturated with water if untied.  I find that the one-inch of slack is enough to wind up with a pretty solid, easy to move bundle that will be heavier than might be expected when soaked. I do it the same way each and every time.  One such bundle will stop most expanding 9mm, .357, and .38 Super rounds.  If testing more penetrating rounds, prepare two such bundles and sit one atop the other.


I shoot from approximately 3' away and can usually get about 12 shots per bundle in 4 rows of 3 shots each.

Be sure to shoot straight into the wet pack  so that subsequent shots in the immediate vicinity don't get into a "wound channel" already made.


It's been said that firing into wet newsprint causes jacketed bullets to expand. Above is not a jacketed bullet but a plated Rainier 124-gr. that was fired into wet pack in excess of 1100 ft/sec.  These bullets are not as robust as truly jacketed ones and it did not deform.


When I've shot all the rounds I can fire into one bundle of wet pack, I take a thin rod approximately 16" long and insert it into the respective holes and measure the distance the back of the bullet penetrated and jot it down on my note sheet.  When this is done for all the holes, cut the strings and begin pealing back the layers of soggy newsprint.  I collect fragments along the way, but don't be surprised if some are lost.  I remove the expanded bullets, take them home, clean 'em up, and measure their expanded diameters in two places as well as the height of the bullet.  I then weigh it.


I do the same thing when using water bottles except that I shoot from farther away as the splash is far too much at 3 feet!  I usually shoot these at approximately 10 yards to avoid being drenched.  I do not attempt to gain any kind of penetration figures when shooting water.


Usually four to five 2-liter pop bottles filled with water and shot sideways will stop most expanding .38, 9mm, .357, and .38 Super rounds. JHP bullets from .380's and 9mm Makarov can usually be stopped in about 3 bottles.


It's been my observation that expanding bullets tend to shed their jackets much more frequently in water than in wet pack.  The reason is that the water can so easily get between the jacket and the lead bullet. I have not seen this happen with Speer Gold Dots, which truly do have the jacket and core bonded together.

At this time, I've not tried any other bonded bullets. With practically all other bullets, expansion in water has sometimes resulted in core/jacket separation. Such does not occur with near the frequency in wet pack and I suspect, gelatin.  While I've recovered fewer expanded bullets from animals than from "test media," except for Triton, Glaser, and Corbon, the jackets have not separated from the bullets.


This 124-gr. standard pressure Hornady XTP was recovered from wet pack.


The 124-gr. Hornady XTP on the left was recovered from a javelina and had a muzzle velocity of about 1244 ft/sec.  The animal was about 30 yards away. The 124-gr. XTP on the right impacted water at about 100 ft/sec less.  Even so results are similar to both the higher velocity XTP recovered from the animal and the one shown in the previous photo.  Though it didn't occur in this case, I have seen XTP's shed their jackets in water.  In 9mm and .45 ACP, I've not seen it on animals.


Frequently, bullets recovered from water mimic those fired into wet pack.  Some bullets do not and act very differently in one media than the other.  This is the primary reason I "test" in both water and wet pack.


These Hornady 147-gr. 9mm XTP bullets were fired into water using a 5" 1911 and a handload that propelled them at an average velocity of 1183 ft/sec.  You can see that the top bullet is trying to slip its jacket.


Wet pack will understate penetration compared to tissue or 10% ballistic gelatin. By how much seems to vary with bullet weight and impact velocity.  In other words, I've not been able to come up with a fairly constant ratio between the two that holds true for all calibers or even different bullet weights in a specific caliber. Doing the math for over twenty 115 and 124-gr 9mm JHP's resulted in a figure that when multiplied by the wet pack penetration depth very closely matched reported penetration depths in ballistic gelatin, but the same number did not hold true when going to 147-gr. bullets.


These 9x18mm Makarov Hornady 95-gr. XTP bullets were recovered from wet pack and water.  Results are very similar.


Both bullets shown here are PMC 95-gr. Starfire JHP's in 9mm.  The one on the left was fired into wet pack.  The one on the right was fired into water.  Notice how the JHP separated from its jacket when impacting water.


At this time, if you'll add about a third of the bullet's penetration depth in wet pack, you'll be in the ballpark as to what it will probably do in tissue or gelatin.


Here are some 9mm (left) and .38 Super loads that were fired into water. The far left expanded bullet is a Winchester 127-gr. +P+ while the expanded bullet at the top next to the unfired slug is a 124-gr. XTP. At the bottom is an expanded 124-gr. PMC Starfire. The expanded bullet at the top right is a 147-gr. Hornady XTP. At the far right is a Corbon 125-gr. JHP and at the bottom a 147-gr. Golden Saber.  Usually the Corbon will fragment more than this in water.  The Golden Saber's bullet is beginning to slip the jacket and such is not uncommon in water.  This same load gave both expansion and complete broadside penetration in a deer.  No evidence of either fragmentation or jacket separation was found.


When information from this sort of testing is viewed on message boards, it's not unusual to see replies similar to, "Well, if I'm ever attacked by a wet newspaper, I know what load to use," and similar lofty comments of expertise. Others decry it as being meaningless or the major bullet testers would use it. The first comment is usually not worth replying to, but there is some truth in the second.  Water and wet pack testing are not as meaningful as closely monitored testing in which ballistic gelatin is used, but neither is it "meaningless."  Even testing done under the repeatable conditions insisted upon by the scientific community results in differing figures. There's enough variation in ammunition characteristics lot to lot as well as firearms that it cannot be exact.  All of this is an estimate or indicator of what will probably happen. I think the gelatin testing is the best, but at the same time I do not believe that laboratory type work tells the whole tale.  Unfortunately, obtaining live media is either illegal, too time-consuming (hunting), or under such varying conditions as to make it "meaningless" to some.  "Stopping power" and bullet performance are two very heavily debated topics and both can lead to extremely hard feelings.  I'm not sure why.  I don't get involved in that aspect of it.  This is simply what I do.  The reader can decide what he or she prefers to do…if anything!


The bullet at the upper left was fired into wet pack and fragmented more than the one fired into water (right). These are 9x18mm "Tiger" 95-gr. JHP's.


Though also called "useless," "irrelevant," and of course, "meaningless," I do place stock on what bullets do in living animals. I remain unconvinced that there's no correlation between effects seen on animals and "stopping power" in defensive situations.


Let's see how the informal "testing" I've described compares with admittedly few examples from the field. You've seen the XTP bullet from the javelina compared to the ones fired into water and wet pack.


Each of these bullets is expanded 9mm Winchester 127-gr. RA9TA JHP's. The one at the lower left was fired into wet pack. The one at the bottom right was fired into water and the one at the top was recovered from a deer I killed with it. Are the results exact?  No, but fairly close in my view.


With the exception of the "wound channel" at the upper right, the ones shown here are fairly typical for those seen in wet pack.  The one at the upper right is from RBCD extreme velocity ammunition.  Keep in mind the average size of the other "wound tracts" while looking at the picture below.


This is the interior of the deer's chest cavity that was hit with the expanded Winchester JHP shown in the previous picture. This is an inside view of the cavity where the bullet entered the animal's body.  I'm not saying that it's exactly the same as that shown in the wet pack, but it is similar.


Here you can see the zone of destruction where it grazed the heart. Again, not the same, but not worlds apart, either.


I've seen this sort of thing on other occasions, but don't have the photographs to share.


None of the "testing" I do is intended to "compete" with anyone or any group.  I do it for myself.  If you are interested in doing the same, I think you can easily see how.


Judge for yourself if it's completely "meaningless" or if it might be of some use to you.


It's cheap enough and just takes time.