I know I'm not the only one that has wondered if there was any real difference between Hornady Critical Defense and Hornady ZombieMax other than the nickel plated brass case, color of the hollow point plug insert, and packaging. Google it and you will find a few instances where this discussion has come up on various gun and ammo forums. Many months ago I decided I would test it and find out if there were any significant differences between the two. I think I bought the ZombieMax ammo back in March, but never got around to testing it.
You may know that I recently started using a new ballistics testing gel from Clear Ballistics. This test was run on the first outing with the new gel 3 weeks ago, but I didn't have the chance to take the pictures, produce the video, and write up the blog until this week. The really nice things about the gel are the crystal clarity and the consistent density. The picture below shows a 600 fps calibration BB that was shot into the gel and came to rest at slightly over 3.25". Right in the 10% ballistics gel calibration range of 3.25" to 3.75". This close up picture also shows how easy it is to really see the details of the bullet's path, stretch cavity, and rotation as it travels down the length of the block.
Going into the test, I realized that I would need to take more than one test shot with each load to come up with a definitive result. Ideally, I would pull rounds from different lots of ammo just in case one sample was out of spec. Unfortunately, I don't have that luxury so this test is as definitive as it can be based on a sample size of 1 from 1 box of each type of ammo.
Kahr P380 with 2.5" barrel
My testing process is pretty simple. I take one shot with each ammo type at the end of a Clear Ballistics Gel block. I take the shots from 8 feet away and impact velocity is measured 2 inches away from the Gel. Immediately prior to the terminal test, I shoot a five shot velocity test string from 8 feet over a Competition Electronic ProChrono Digital chronograph.
When I was done testing, I had one clear gel block with two expanded Hornady rounds in it as well as the calibration BB that was resting between the two bullet paths. The picture below was taken from the top of the block. The upper wound channel was the Critical Defense and the bottom channel was the ZombieMax.
The video below documents the entire test at the range. Bullet recovery is now done off video camera with still photos like the one directly above.
My Analysis and Thoughts
The next picture was taken though the bottom of the block and again highlights the significant difference in wound channel caused by the tumbling bullet. The Critical Defense remained straight and true through its entire trip into the block, while the ZombieMax tumbled and came to rest facing straight down. Just to the right of the ZombieMax bullet you will see a copper petal resting in the wound channel. It was physically separated from the bullet during the trip through the block.
At this point I was almost overcome with the "cool factor" of the gel and considered cutting out just this piece of gel shown in the picture and turning it into a paperweight. Ultimately, I decided against it because I really needed to measure the expansion and final weights of the rounds.
The next picture introduces the ruler and we see that the two rounds penetrated between 9.5" and 10.5". Well short of the "magic" 12", but still a respectable performance for light bullets driven at modest velocities.
If you watched the video, or jumped ahead to the data sheet below, you may have noticed a large difference in velocity between the two loadings. ZombieMax averaged 65 fps faster than Critical Defense in the 5 shot velocity test. ZombieMax was 60 fps faster than Critical Defense on the test shot into the block. Hornady publishes a velocity of 1000 fps for both of these loads. Not sure what barrel length they are using, but we didn't get close to that with either load. You may also notice that the ZombieMax bullet had two petals shear off the jacket. I'm not sure if that was a factor due to the increased velocity or caused by the bullet tumbling. The two petals were not included in the ZombieMax bullet recovered weight, but are displayed with the bullet in the data sheet below.
At this point of my test recap, I'm wondering if Hornady has indeed beefed up the velocity of the ZombieMax load. This is far from scientific evidence, but if you look at the two vertically oriented round samples below you may notice more cannelure is visible on the ZombieMax bullet than the Critical Defense load. This may indicate a heavier powder charge in the ZombieMax case that requires the bullet to be seated with less depth than the Critical Defense. Also it appears the two loads have different colored primers. The primer used in the ZombieMax round may be a hotter mix than the primer used in the Critical Defense load. I also checked the outside diameter of the brass to make sure one or the other wasn't larger and potentially providing a better gas seal in the chamber, but both measured similar dimenstions.
Unsatisfied with my findings up to this point, I dropped a few rounds of each load on the scale. I can say the ZombieMax cartridges were averaging 2 grains heavier than the Critical Defense. If some of that weight difference was additional powder, we may have a reason why the ZombieMax was generating the additional velocity.
Overall, it was a fun test to run. I'm not sure I proved anything other than if I was given a choice between Critical Defense and ZombieMax, I'd take the ZombieMax for no other reason than it runs faster than the Critical Defense. When it runs at 900+ fps, look what happens to the bullet. In the picture below you can see the jacket petals have pulled all the way back to the bottom of the bullet base. The Critical Defense petals have only peeled back to the middle of the bullet shank. Greater expansion + greater penetration = Win for ZombieMax. The tumbling bullet and larger wound channel is just a bonus that I don't think would repeat with additional tests.
Disclaimer....This test should not be considered an endorsement or recommendation for the product(s) tested. It is up to each individual to make their own personal decision about which specific ammunition to use for their needs. It's also critically important to test any ammo in YOUR SPECIFIC FIREARM before relying on it for any purpose. Ammunition labeled as +P should not be used in any firearm unless the firearm manufacturer specifically states you are permitted to do so.