Monday, September 3, 2012

380 FMJ vs. JHP Permanent Wound Channel Test

Over the 2011 July 4th holiday weekend, I completed my testing and published my comprehensive testing results from 32 varieties of 380 ammo.  If you have not seen the test, you can see it HERE.  It whet my appetite to dig deeper into ballistics testing and continue my testing beyond simple velocity and energy measurements and push forward with terminal testing.

Though the Winter, I designed and constructed a series of prototype bullet traps using a wet hyper-absorbent polymer ballistics catch media.  Unfortunately, I failed to find a box design that could stand up to the shock waves of energy generated when the bullets impacted the media in the box.  The boxes would literally explode from internal pressures. 

In the Spring of 2012, I got decided to get a batch of Corbin's SIM-TEST ballistics testing media after trading a few messages about it with YouTube ammo testing legend tnoutdoors9.  I immediately started testing many of the most popular 380 jacketed hollow point loads to see how they would perform from short barreled pocket 380s.  Since March, I've tested over a dozen of the most popular 380 JHP loads.

The folks that carry 380 pistols are a very polarized group.  Many want to know the best terminal performing jacketed hollow point ammo and the rest are in the group that thinks that full metal jacket ammo is the only ammo that will penetrate deeply enough to be effective.  I've managed to steer clear of the debate for over a year and just concentrate on practicing with my chosen best performing JHP load that I discovered in my terminal testing.

One interesting thing about SIM-TEST, is that it doesn't like heat.  It also doesn't like water.  It's a water soluble compound with a very low melting temperature.  The low melting point is a good thing for recasting new test blocks, but a bad thing if you try to use it in high ambient temperatures with full sun exposure.  This Summer had been very hot and sunny in my area (bad drought actually), so my terminal ballistics testing stopped in early June.  All the "new" ammo tests that have gone up on the blog were actually tested in June and I've been slowly releasing those tests throughout the Summer.

Last weekend we got a little break in the heat and I was able to cast some SIM-TEST blocks and do some terminal tests.  I was using a new SIM-TEST block mold and found out that I had quite a bit of scrap block left over after testing.  Part of the reason for so much scrap was that 2 of the 4 tested rounds failed to expand and passed through the media block as any FMJ load would.  It was interesting to see the the wound tracks of the bullets that failed to expand.  The tested .380 that failed to expand, had a very small wound channel with negligible stretch cavity and permanent wound channel.  See picture below with failed 380 on the right and expanded 9mm on the left.

It made me just curious enough to try a head to head test of my favorite FMJ and JHP loads in the left over scraps.  I wasn't interested in seeing their penetration depths or measuring the recovered bullets, I was mostly interested in their performance during the first 6 inches of travel into the SIM-TEST block.

Testing Protocol:
My testing process today was fairly typical.  I took one shot at SIM-TEST block that was loosely draped with 2 layers of medium weight denim.  I took the shot from 8 feet away and impact velocity was measured 2 inches away from the SIM-TEST block.  These blocks were very hard compared my usual blocks.  I had written them off a scrap and placed them in a lidded bucket for future remelting.  The blocks harden as they lose moisture and these blocks had lost quite a bit of moisture.  My calibrated SIM-TEST blocks are always wrapped in plastic to maintain their moisture content.

Test Pistol Specs:
Kahr P380 with a 2.53" barrel

The video below documents the test from the range through bullet recovery at home.

My Thoughts:
First off, if you read the blog you know I never suggest you go out and buy anything.  I really try hard to stop short of recommending any specific product or service.  If I like something, I let you know that.  If I don't like something, I let you know that too.  While I am not recommending the two specific 380 loads tested in the video, I will say that I like them both very much based on their previous performances in my testing.  Read between the lines and you now have a good idea what 380 ammo I carry and you can stop asking me that question.  =)  Please do your own testing with your personal 380 pistol to assure reliability of function before using any ammo brand and load seen on my blog or in other ammo reviews.

After cutting open the blocks at home, I have to admit that I've got more questions now about FMJ vs. JHP than I ever did before.  You can't ignore the permanent wound/stretch cavity from 1 to 3.5" inches into the Federal Hydra-Shok test block on the left.  After expansion, the .518" expanded round continued to penetrate until it ran out of energy.  This was typical of the Federal Hydra-Shok performance I've seen in all my previous testing.  At first glance the Hydra-Shok (left) looked like a run-away winner and had generated 164 foot pounds of energy with its entry speed of 905 fps.  Contrast this with the permanent stretch cavity of the UMC FMJ test load in the block on the right.

What was very interesting to me was the large permanent wound channel I found in the Remington/UMC Leadless Flat Point test block starting at about 4 inches into the block.  While I had to carve a bit of SIM-TEST away from the site to find it, I did not create the cavity, but only exposed it by removing an extra bit of media.  This wound channel looked much larger and much more permanent than the channel caused by the 380 JHP that failed to expand last weekend.  I have to assume this was caused by the flat point profile of the Remington/UMC bullet tested today.  After exiting the block the round traveled through 3 one-gallon water jugs and buried itself in the dirt berm.  I looked for quite some time, but couldn't find the bullet.  That's some impressive penetration and the evidence of a permanent wound channel has really opened my eyes to the potential effectiveness of this load.  This test shot generated 174 foot pounds of energy with an entry speed of 918 feet per second.

I'm really glad I did this test.  Not that it brought out any specific answers to the question of FMJ or JHP in 380, but it did open my eyes that there is more here that needs to be studied. 

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. 

1 comment:

  1. I believe that the stretch cavity from the UMC is due to toppling. When the bullet topples and penetrates side first, this can present a larger surface area to the block then an expanded JHP. A JHP that fails to expand will general not topple until very late in the wound track. Therefore an FMJ is generally more effective than a JHP that does not expand. Something to consider is that a toppling FMJ is likely to veer off course while and JHP expanded or not is more likely to penetrate in a straight line. Just food for thought.