Tuesday, December 11, 2012

Speer Gold Dot Multi-Caliber Stress Test

I can't remember when I first thought about trying this test, but it was on my mind for several months before I actually had the chance to run the test.  Much of the credit for the test has to go to Clear Ballistics for giving me one of their scorched blocks that went off-color during processing and did not pass their quality assurance standards for color.  Rather than discard the off-color block it was offered to me for whatever purpose I could dream up for it as long as I let folks know that while the block met density standards, it did not meet their color standards.

My test idea was to run some popular hollow point bullets in the gel, but instead of just bare gel I would introduce some barrier material in front of the block.  I had a big swatch of thin tanned pig skin leather that I had purchased back in March.  When I purchased it, my original plan was to soak it in water and put one layer under my standard two layers of denim to simulate skin.  What I discovered was that soaking the leather was impossible because the leather refused to absorb water.  It was also much tougher than I expected it would be.  I ultimately decided to use 3 layers of the pig skin and two layers of medium weight denim for this test.

I grabbed three different calibers of ammunition that were all loaded with Speer Gold Dot Bullets, in popular bullet weights, for the test.  No logic went into the decision of what to test other than I just happened to have some of each of these three on hand.  The specific details on each load and the recovered bullet from each test are shown in the pictures below.  







A few weeks ago, I posted a blog article about the versatile Glock 27 that can be a multi-caliber pistol with a simple magazine and barrel change.  All velocity testing and terminal test shots were taken with the Glock 27.  Lone Wolf conversion barrels were used for the 9mm and .357 Sig tests.  The stock factory barrel was used for the .40 S&W test.  All barrels are approximately 3.5" long.


Each test was documented and produced as an individual video.  The videos contain the 5 shot velocity tests, high speed camera footage of the bullet traversing the clear gel block, still picture capture of maximum stretch cavity, and detailed analysis of the wound channel left in the clear gel block.


The videos have been up for several days and I've received several inquiries about the final expanded diameters of the recovered bullets.  Initially, I didn't plan to include any specific data about the bullets because this was just a trial run of the new test protocol and the testing process may change if I decide to run another stress test.  I've received enough inquiries, that I measured all three min and max expanded diameters.

9mm -       .397 min     .502 max
40 S&W -  .483 min     .552 max
357 Sig -   .507 min     .544 max

Unfortunately, I know the testing process will have to change if I decide to run this test again.  I discovered that the pig skin leather I was using would flash (combust) due to either the heat, pressure, or some combination of these two, as it was pushed through the gel block.  In the high speed footage, you can literally see 1 or 2 of these fireballs in the wound channel of each test shot.  You can also see a large amount of smoke pouring out of the bullet entry point in the 40 S&W test video.

After I recovered the bullets and documented the wound channel artifacts left in the block, I started cutting into the block to extract all the denim fibers and leather pieces left in the block.  This was an incredibly tedious process that left me with the hand-plucked pile of denim and leather pieces shown below.  Several gel pieces will have to be discarded because the soot from the fireballs can't be cleaned from the gel.


If I run this test again, I will skip the denim and locate some verified vegetable tanned leather to replace the pig skin.  This may eliminate the flashing problem with the leather, but we won't know for sure until we try it.  I don't believe the two layers of denim added enough to the barrier to be worth the effort of cleaning it out of the block.

My Thoughts:
I was really surprised by the results of this test.  This was my first opportunity to shoot through a barrier other than simple 2 or 4 layers of denim.  Two layers of denim never caused a significant impact on bullet expansion in previous tests.  4 layers of denim would impact some of the slower and lighter 380 Auto bullets, but didn't really stress calibers 9mm or larger.  The leather was a real game changer and proved to be a significant barrier that impeded the expansion performance of everything except the .357 Sig.

All recovered rounds were within 1 grain of their published bullet weight.  All rounds penetrated at least 16".  As I mentioned in the .357 Sig video, it was the only bullet that had to be pulled from the gel block.  The 9mm and 40 S&W bullet noses both cleared the block and were ultimately stopped by the phone book backing the gel block.  I wouldn't say that any tested load was a failure.

The epiphany for me was the performance of the .357 Sig load.  Prior to this test, I had never shot .357 Sig, so I had only heard about it's terminal performance virtues from tests others have done.  I generally dismissed the round as an expensive niche caliber.  To see it preform as it did under similar conditions as the 9mm and 40 S&W test shots was the real ah-ha moment when I discovered something new.  For me, the ah-ha moments have always been the payoff from my testing.

Ideally, I'd like to find a dedicated 357 Sig pistol that could work for both "in the pocket" or IWB carry.  I'll probably start practicing with the G27 and 357 Sig conversion barrel.  Currently, I'm not satisfied with my ability to control the small Glock and may need to step up to something a bit larger like the Sig P239.  A Glock 32 is another option, but I have a difficult time hiding the mid size Glock grip frames IWB with appendix carry.  Two additional wild card choices that may or may not be available could be the new Sig P224 or perhaps Springfield will come out with a 357 Sig version of their XDs.  A 357 Sig XDs would be my first choice over anything I've previously mentioned.

Alternately, I'm really curious to see how the lighter 40 S&W 155 grain Gold Dot bullet would do on a retest.  The short barrel Glock 27 had no problem exceeding the published 1050 fps muzzle velocity of the 165 grain load.  The 155 grain Gold Dot load boasts a published velocity of 1200 fps.  Perhaps the additional speed of the 155 grain load will allow it to fully expand after clearing the stress test barrier. 

Then there are all the other bullet families to test.  Requests to run similar tests with Federal HST, Tactical Bonded, Winchester Ranger T, and Hornady Critical Defense/Duty have been flooding my in box.  There is so much to test and so little time available that I'm not sure I will have the chance to get to them all. 

I'll close this out with one more picture of our test subjects in a side by side comparison photo.  It was a fun test, and I think I learned a few things.  I'll probably take what I learned from this test and try it again in the future.


Disclaimer....This test should not be considered an endorsement or recommendation for the product(s) tested. All tests represent actual performance in ballistics testing media. Terminal performance in all other media will show different results. It is up to each individual to make their own personal decision on 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 or +P+ should only be used in firearms that have been certified by the manufacturer as safe for the additional pressures generated by these ammunition types.

5 comments:

  1. Doesn't count if you don't use Glock OEM barrels in the testing!!! Just kidding Bruce, really. You did a phenomenal job on the simulations. Eric over at gunmartblog posted this up early AM today and I'll be sharing it with my crew too. VERY useful test. Will love to see it expanded with other rounds and bullet types.

    ReplyDelete
    Replies
    1. Thanks Ebbs. I appreciate the pick up.

      Delete
  2. This test makes a very strong case for the new Critical Duty line of ammo....

    ReplyDelete
    Replies
    1. Maybe or maybe not. I wouldn't rush to any conclusions from just this one trial test. I still need more data points.

      Delete
  3. Interesting tests, thanks as always for taking the time Bruce. I will point out one thing with the Speer 165gr - the old load (53949) was listed as 1050 muzzle vel, but the contemporary load you tested here (53970) is listed at 1150 ft/s from a 4" barrel on the ATK website. From other chrono results I've seen, the 53970 tends to run slower than advertised, so I'm not too surprised at the 1069 average from the G27 here.

    I run the 165gr GDHP only in 4" barrels and the Kahr K40 (have seen some really nice chrono results from the K40, on par with velocities from G23).

    -Roger

    ReplyDelete