Thursday, February 28, 2013

Caracal Recall - Model C

I usually don't post stuff like this, but I've been following the Caracal brand this year in hopes of getting my hands on a Caracal SC model as part of my 2013 Wish List.  I just happened to notice this press release notice on Facebook this morning.  FULL RECALL NOTICE ON THE CARACAL WEBSITE


This follows an initial recall initiated on October 19, 2012 and updated on November 24, 2012 that affected some group of F and C model pistols.  The remedy for the initial recall was a replacement pistol.

All this is unfortunate and it makes me wonder if the brand can overcome 2 recalls in a 5 month period for two different safety issues.

With so much recall activity going on, coupled with the crazy demand for everything gun related, I seriously doubt I'll see a SC model this year.      

Wednesday, February 27, 2013

Speer Gold Dot .357 Magnum 158 Grain Stress Test

 
As a follow-up test to a previous test in bare gel, I ran a second test with the 158 grain 357 Magnum load through the leather and denim stress test.  This article recaps that test.  

Test Pistol Specs:
Smith & Wesson 686 +  4" Barrel


Testing Protocol:
My testing process is pretty simple.  I take one shot at the end of a Clear Ballistics Gel block that measures approximately 6" x 6" x 16" and weighs approximately 16 lbs.  I take the test shot from 8 feet away and impact velocity is measured less than 2 inches away from the block.  Clear Ballistics Gel is calibrated to 10% ballistics gel density.  I shoot the block at the range and then bring it home to analyze the block and recover the bullet.  Immediately prior to shooting the block, I take a 5 shot velocity test over a ProChrono Digital chronograph.

Stress tests include an additional barrier of Hermann Oak 5/6 ounce tooling leather and 2 layers of medium weight denim in front of the gel block.


Test Results:
The test results are summarized in the data sheet below along with a close up shot of the recovered bullet.



Video documentation of the entire test from range through bullet recovery is available below.  The high definition video is best viewed on YouTube, but you can also view it here.

My Thoughts on This Load:

In the previous bare gel test, this load did well.  It expanded and penetrated to an amazing 23" in bare gel.  Unfortunately, the results were quite different in the stress test.  If nothing else, it validates that the stress test really does put a considerable amount of stress on the dynamics of bullet expansion.  In the close up picture of the bullet you can see that the petals were trying to expand, but it just didn't happen.  Based on the leather plug recovered from the wound channel, I believe the leather completely plugged the hollow point cavity until the bullet tumbled 180 degrees and the leather plug was dragged out of the bullet nose.  The recovered leather plug actually had a convex shape on one side that exactly matched the concave of the hollow point cavity.

Wrap Up:
While terminal performance was disappointing, there were some new learnings that came out of this test.  The first was that the stress test does indeed live up to the name I gave it.  It is going to be really interesting to see how the future stress tests play out with other loads that performed well in bare gel testing.

The second neat thing was seeing the wound channel left by the tumbling bullet.  Since the bullet tumbled at a high rate of speed, it left a very large permanent wound channel behind it.  I think of it like a log floating down a river and running parallel with the river current.  This log leaves very little disruption in the river when moving along with the current.  Turn that log 90 degrees and put the long side against the current and you've now got a major disruption to the surface of the river. We saw that disruption in the gel block.  

The third, and possibly most interesting, observation from this test was the penetration depth change caused by the bullet tumbling.  In the bare gel test, the expanded bullet traveled 23 inches down the gel block.  In this test, the unexpanded bullet should have penetrated much deeper, but because it tumbled and lost energy it only penetrated to 22.5 inches.
   



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.

Thursday, February 21, 2013

Liberty Ammunition Halo Point 9mm Clear Gel Test


 
Earlier this week I introduced you to Liberty Ammunition and the Halo Point Civil Defense product line.  Rather than rehash that information, I'll just point you to the 40 S&W test recap if you want to read up a bit on Liberty Ammunition and the concept behind the Halo Point products.  In this article we will be looking at the 9mm Halo Point load.  I do want to make note of one key difference between the previously tested 40 S&W and the 9mm featured in this article.  The 9mm packaging states that it is:  "Designed for use with firearms rated for +p ammunitions."

A note of thanks to the folks at Ammunition Depot for supplying the samples for this test.

Test Pistol Specs:
Kahr PM9 with 3" Barrel

Testing Protocol:
My testing process is pretty simple.  I take one shot at the end of a Clear Ballistics Gel block that measures approximately 6" x 6" x 16" and weighs approximately 16 lbs.  I take the test shot from 8 feet away and impact velocity is measured less than 2 inches away from the block.  Clear Ballistics Gel is calibrated to 10% ballistics gel density.  I shoot the block at the range and then bring it home to analyze the block and recover the bullet.  Immediately prior to shooting the block, I take a 5 shot velocity test over a ProChrono Digital chronograph.

Test Results:
The test results are summarized in the data sheet below along with a close up shot of the recovered bullet.


Video documentation of the entire test from range through bullet recovery is available below.  The high definition video is best viewed on YouTube, but you can also view it here.


My Thoughts on This Load:
I had to dig back in the archives, but I finally located a previous 9mm test with a conventional hollow point that generated virtually identical energy as our Halo Point 9mm test shot.  As we saw in the previous Halo Point 40 S&W test, the energy transfer from the bullet to the block is quite different than with a conventional hollow point bullet.  We again saw a massive round stretch and fragmentation cavity followed by the tail of the bullet base as it progressed down through the block.
 
Liberty Halo Point 9mm - 328 ft/lbs of Energy
Speer Gold Dot 9mm +p 124 Grain - 327 ft/lbs of Energy
I have no comment on the advantages or dis-advatages of either bullet design or expansion signature captured in the block.  My goal is simply to provide you with a visual representation of what the terminal effect looks like as each bullet passes down through the Clear Ballistics gel block.

Velocity and Energy:
As we have seen in other 9mm tests, the short barrel used for this test had a big impact on velocity.  The 5 shot velocity average registered almost 200 ft/second slower than the published 2000 ft/second for this load.  As sometimes happens, our terminal test shot ended up being the slowest shot of the test and came in almost 300 ft/second slower than the advertised velocity.

With the lower velocity, we also saw reduced energy.  In order for this 50 grain bullet to make the 500 ft/lbs of energy published on the box, velocity would need to be 2125 ft/second.  That may be possible in a service length barrel and is worthy of a retest in a longer barrel.  I did notice the website lists 450 ft/lbs of energy for this load.  I feel that the 450 ft/lbs is more realistic with this bullet weight.

I hate to keep referencing back to the 40 S&W test, but we did not see such a dramatic difference in velocity or energy with the short barrel 40 S&W test.  All other 40 S&W I have tested in the past seems to suffer less velocity loss in shorter barrels.  It appears that the same holds true for this load.

Fragmentation and Weight Retention:
I recovered 8 fragments and the bullet base from the gel block.  I believe I recovered all the pieces, but I may have missed one since the combined total recovered weight came in at 48.6 grains or 97.2%.

Penetration:
Penetration depth of the bullet base was 9.875 inches.  The website information on this round claims 12 inches of penetration when tested in the industry standard test barrel length.  Again, I think the shorter barrel length was a significant contributing factor to the reduced penetration depth observed in this test.

Wrap Up:
As I wrote up the articles on the 9mm and 40 S&W tests, I had the chance to really look into the details I had captured on video.  The picture below shows the gel block at rest after absorbing the 40 S&W test shot.  It's a unique view that I didn't pick up on immediately because I had to enlarge a section of the video frame to really see the detail.  What surprised me in the picture was the uniform distribution of the fragments as they branched out from the central wound channel.  For reference, remember that the block is 6 inches wide. 


One other point I wanted to mention that wasn't obvious to me at first.  The Kahr PM40 holds 6 rounds.  The 6 rounds of Hornady Critical Duty 175 grain 40 S&W ammunition I was carrying weigh 3.4 ounces.  If I replaced those rounds with Halo Point 40 S&W, total ammunition weight is reduced to 1.9 ounces.  That's a 44% reduction in weight and would be even more noticeable in a higher capacity pistol like a Glock 27.  Weight savings in the 7 round PM9 loadout was 39% when compared to conventional 9mm 124 grain loads.

I really enjoyed testing the Halo Point ammunition because it is so different than anything I have previously tested.  I'm looking forward to reading the test results of others and also circling back with a long barrel test at some point in the future.  There is a 45 ACP version of this load available, but was not available at the time the testing was conducted.  



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.

Tuesday, February 19, 2013

Liberty Ammunition Halo Point 40 S&W Clear Gel Test


I really enjoy testing new stuff that is truly unique and different.  This new ammunition from Liberty Ammunition falls right into that category.  The folks at Ammunition Depot asked me if I would be interested in testing the ammunition and after looking at the box art on line, they had me hookedHalo has been one of my favorite game franchises since Halo Combat Evolved made its debut on the original Xbox over a decade ago.  The Halo Point logo bears a strong resemblance to the Halo video game logo as you can see in the picture below.

   

Aside from the box art, there was also the ammunition itself that piqued my interest.  Liberty Ammunition proclaims to be the World Leader in lead-free high performance ammunition.  I have no reason to doubt that claim.  The Halo Point Civil Defense ammunition line consists of offerings in 45 ACP, 40 S&W, and 9mm Luger.  I received samples of the 60 grain 40 S&W and 50 grain 9mm for testing.  Thanks again to Ammunition Depot for the samples.

For the sake of brevity, I'll paraphrase the concept behind the Halo Point ammunition line.  The lead-free bullets, used in the Halo Point loads, are described as fragmenting monolithic hollow points.  The lightweight hyper velocity loads generate very high energy by pushing the light weight bullets to velocity levels near 2000 feet per second.  Upon contact with the target, the nose of the bullet expands and fragments into a group of small pieces.  The bullet base remains in-tact and continues to penetrate deeply into the target.  The key selling points appear to be high energy, reduced recoil, and "significant results in terminal effects".

Having a rough idea what to expect, it was time to get the ammunition out on the range.

Test Pistol Specs:
Kahr PM40 with 3" Barrel

Testing Protocol:
My testing process is pretty simple.  I take one shot at the end of a Clear Ballistics Gel block that measures approximately 6" x 6" x 16" and weighs approximately 16 lbs.  I take the test shot from 8 feet away and impact velocity is measured less than 2 inches away from the block.  Clear Ballistics Gel is calibrated to 10% ballistics gel density.  I shoot the block at the range and then bring it home to analyze the block and recover the bullet.  Immediately prior to shooting the block, I take a 5 shot velocity test over a ProChrono Digital chronograph.

Test Results:
The test results are summarized in the data sheet below along with a close up shot of the recovered bullet.


Video documentation of the entire test from range through bullet recovery is available below.  The high definition video is best viewed on YouTube, but you can also view it here.


My Thoughts on This Load:
Over the last year I've built up a decent body of knowledge on terminal performance after conducting all kinds of terminal tests on a wide variety of ammunition.  Unfortunately, none of that applies in this case because this is the first intentionally fragmenting load I've tested.  I can make some sweeping generalizations on how this load differs from others I've tested.

I'll start with a discussion of the maximum stretch cavity.  For the picture below, I grabbed a video frame showing the maximum stretch cavity size.  This is very unique and different than anything we've previously seen in our testing.  The stretch cavity is almost round and very close to 6 inches tall.  As we saw in the video analysis of the gel block artifacts, the stretch cavity is really the fragmentation cavity where the bullet is breaking apart and sending 17 fragments out in a circular pattern from the primary wound channel.  The tail to the right of the fragmentation cavity is the bullet base, or 18th fragment, that continued to penetrate more deeply into the gel block.  Calculated energy was 540 ft/lbs. on this test shot.

Halo Point 40 S&W 540 ft/lbs of Energy

Contrast this with the maximum expansion cavity created by a 125 Grain 357 magnum load traveling at approximately 1400 fps and generating 549 ft/lbs of energy.  The picture below displays the energy transfer and stretch cavity we have come to expect from traditional expanding bullets.  The horizontal vortex is very symmetrical and decreases in size as the bullet penetrates deeper into the block.  This is the only clear get test I have that matches approximate energy.  All previous 40 S&W tests generated energy between 350 and 370 ft/lbs.

Speer Gold Dot 357 Magnum 549 ft/lbs of Energy
Wrap Up:
As I type this up nearly two weeks after I ran the terminal test, I'm still mentally shaking my head in disbelief at the velocity generated by this load in the short 3" Kahr test barrel.  I can only imagine what would show up on the chronograph if I retested this in a full size service pistol.  Conventional wisdom dictates longer barrel = higher velocity, but without actually testing we won't know if that holds true for this load.  Prior to the test, I did have some concerns about cycling with this lighter than normal bullet, but in my limited testing I had zero failures with feeding or extraction.  In retrospect, I probably should have loaded two Halo Point rounds behind two conventional 165 grain JHP defense loads to compare "felt recoil".  I guess I'll save that test for a later date.  

From this one test, the Liberty Halo Point appears to perform as advertised.  The light bullet delivers on the velocity and fragmentation fronts, but fell short on the penetration claim of 12 inches.  Liberty doesn't mention the media they used to develop their penetration data or test barrel length.  A retest in a longer barrel may allow the round to penetrate to the full 12 inches.  The box states that the bullet will fragment into up to 7 pieces.  When I was done extracting all the fragments I had 18 in total and had accounted for 100+% of the published bullet weight.

So is the Halo Point Civil Defense, from Liberty Ammunition, the future of personal defense ammunition?  I think we need to hear some reports from the field before we can make that assessment.  My goal with this article was simply to demonstrate how the ammunition performs and capture a series of performance measures.  Stop back on Thursday for the 9mm Halo Point test results. 



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.

Thursday, February 14, 2013

Hornady Critical Defense 32 NAA 80 Grain FTX Clear Gel Test

 
For the milestone 200th blog article, I'm going back to my mouse gun roots with a .32 caliber ammunition test.  I've been waiting to get my hands on a box of this stuff since the first day I read about it coming to market.  As a bonus, this ammunition was actually on my 2013 Wish List.  

This new load from Hornady is an extension of their very popular Critical Defense line of self-defense ammunition.  If you've never heard of 32 NAA, I'll give you the 10,000 foot overview on the cartridge.  The 32 NAA is a bottle-necked pistol cartridge spawned from the 380 Auto.  In the picture below you can see the 32 NAA and 380 AUTO side by side.  A 32 NAA is formed by necking down a 380 auto brass case to accept a 32 caliber bullet.  The concept behind the cartridge is to put more powder behind a 32 caliber bullet than is possible with the 32 Auto cartridge.

32 NAA ammunition is very much a niche item.  Prior to this new release from Hornady, all conventional 32 NAA ammunition was produced by Corbon.  It's nice to have a second company producing 32 NAA ammunition and additional choices in bullet weight.  This new load from Hornady weighs 80 grains while offerings from Corbon are limited to a 60 grain JHP and 71 grain FMJ.   


Test Pistol Specs:
Diamondback DB380MS with 2.8" 32 NAA Barrel

Testing Protocol:
My testing process is pretty simple.  I take one shot at the end of a Clear Ballistics Gel block that measures approximately 6" x 6" x 16" and weighs approximately 16 lbs.  I take the test shot from 8 feet away and impact velocity is measured less than 2 inches away from the block.  Clear Ballistics Gel is calibrated to 10% ballistics gel density.  I shoot the block at the range and then bring it home to analyze the block and recover the bullet.  Immediately prior to shooting the block, I take a 5 shot velocity test over a ProChrono Digital chronograph.

Test Results:
The test results are summarized in the data sheet below along with a close up shot of the recovered bullet.


Video documentation of the entire test from range through bullet recovery is available below.  The high definition video is best viewed on YouTube, but you can also view it here.


My Thoughts on This Load:

Velocity:
Published muzzle velocity for this load is 1000 feet per second.  We came in slightly under that with our 5 shot test string and quite a bit under that with the clear gel test shot.  I purchased this ammunition from what I believe to be one of the largest on-line retailers as soon as it became available so this was probably some of the first batch produced.  Let's hope that Hornady is still fine tuning their production and subsequent batches meet the published velocity specification across all available 32 NAA barrel lengths.

Expansion:
The average expansion of the recovered bullet was .3585".  We can turn this into an expansion ratio by dividing the expanded average diameter by the unexpanded bullet diameter of .312".  The result of the math is an expansion ratio of 1.15.  This means the recovered bullet is 15% larger than the unexpanded bullet.

Weight Retention:
The recovered bullet from this test weighed 79.9 grains with the 1 grain red plug included.  We can convert this to a weight retention percentage by dividing the recovered weight by the bullet weight published on the box.  In this case the weight retention percentage was 99.88%.  Weight retention was excellent with only slight traces of red polymer visible in the wound channel.

Penetration:
Penetration depth measurement gets a bit sticky with this test.  Based on the final bullet resting location, the penetration measured 10.25 inches.  Looking at the gel block and high speed video footage, it's obvious that this load penetrated 12.5 to 13 inches before being sucked back down the wound channel.

I've observed that the bullets that seem to "bounce back" the most are those that maintain the straightest penetration path down the block.  Perhaps an expert on fluid dynamics could estimate the vacuum force generated by the collapsing expansion cavity behind the bullet, but that's way outside of my knowledge base.
  
Energy:   
The calculated energy of the gel test shot was 153 ft/lbs.  To put some perspective around that number, it is slightly more than the 146 ft/lbs. of energy generated by the Critical Defense 380 Auto 90 grain load as fired through a barrel of exactly the same length as our 32 NAA test barrel.  I am referencing back to this specific prior test of the 380 Critical Defense.

Wrap Up:
This load displays all the common characteristics of the Hornady Critical Defense ammunition line with mild recoil, modest expansion, and adequate penetration.  Overall performance is about as good as we can expect from a .32 Auto or .32 NAA pocket pistol.  Regardless of which side of the 32 Auto JHP vs. FMJ debate you fall on, the Hornady Critical Defense 32 NAA demonstrates to me that it is possible to have a 32 caliber bullet expand to greater than 9mm diameter and still get 12 + inches of penetration.

I'm glad I decided to buy two boxes instead of one when I placed my order.



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.

Saturday, February 9, 2013

Taurus M380 Makeover Update - Trigger Job


Back in July 2012, I posted an update on the Taurus M380 mini revolver.  This post covered my original plans for the pistol.  I wanted to break it down and make it a two tone revolver by sending several parts off to CCR for matt black refinishing.  Long story short, I called Taurus about the bead blast media left in the pistol when it shipped and that I thought the trigger was far too heavy.  They offered to take a look at the pistol if I would pay to ship it to them.  When I told them the bead blast media left under the side plate was a quality issue, they wouldn't take responsibility.  So the Taurus lifetime warranty is only as good as your willingness to spend $60 or more to ship the pistol back to them for evaluation and there is no guarantee that they will fix anything while they have your pistol.

I ultimately decided to flush the media out myself and trade it in on a blued model.  Even after taking a loss on the trade, I was still better off than paying to ship the original back to Taurus and then sending parts of it off for refinishing.  I had also read up on what it takes to remove the cylinder from the crane and decided that was outside my comfort zone and gun maintenance skill set.

One nice thing about gun folks, we like to share information.  I had a few readers contact me about the Wolff spring kit I had ordered for the M380.  They gave me some great resources to read and also some advice on things they picked up on when they installed the spring kit in their own M380.  Finally, I read through this document before getting started on the spring swap.  It was very helpful.  Taurus Revolver Disassembly Guide

I've been procrastinating about installing the Wolff spring kit for months.  In a way, it worked out for the best because I recently picked up a new camera that allowed me to document the spring swap process in full.  The lighting wasn't great on the bench or at the range, but I thought it worked out ok for a first attempt.


Bottom line on the spring swap upgrade is that for the paltry sum of $8.00 and an hour of your time, you can turn a difficult to shoot revolver with an overweight trigger into a thing of beauty that is a joy to shoot.  In the video I mentioned that the digital trigger pull gauge maxed out at 14 pounds.  It actually has a 12 pound maximum, but I stand by the 14 pound trigger weight estimate since the hammer had not moved even after the trigger had over 12 pounds of force put against it.  After swapping out the springs, the trigger is now about 9.5 pounds.  It's far from smooth through the entire trigger pull, but it's lighter and easier to shoot quickly and accurately.  For a smooth pull, consult with your trusted gunsmith.  Personally, I'm very happy with the pistol now after changing out the springs and installing the boot grips.  I won't be changing anything else.

There is a risk when you do work like this.  If you make the hammer spring too light, the hammer may not hit the firing pin with enough force to reliably detonate the primer.  The primary reason for the trip to the range this afternoon was to verify that the hammer spring wasn't too light to fire my preferred 380 carry rounds.  If you decide to do the spring swap on your M380 it is CRITICAL that you verify your M380 still works reliably with your ammo choices.

If you want to try this on your own M380, here's the spring kit you need to order from Wolff and all their contact information.  I didn't mention it in the video, but don't get rid of your old factory springs.  Just put them back into the factory shipping box in case you need them at a later date.


Thursday, February 7, 2013

Speer Gold Dot 357 Magnum 158 Grain Clear Gel Test

 
If you have an evil streak in you, drop by a gun related forum of your choice and ask if 125 or 158 grain bullets are better for 357 Magnum personal defense loads.  Let that question hang out on the forum for a few days and come back and read what people post.  If you don't want to wait, you can always google "125 or 158 grain 357 magnum for personal defense" and click through the resultant links to various forums where this question has been previously discussed.  It appears to be quite a controversial topic with proponents in both the 125 and 158 camps.  I see the merits in the arguments coming from both sides of the discussion, but wanted to do my own test and see if one stood out as the better choice of the two.

Last Thursday I published the Speer Gold Dot 125 Grain 357 Magnum test results.  You can see a recap of the Bare Gel and Stress Test by clicking on the links.  This week we're taking a look at the 158 Grain version of Gold Dot 357 Magnum load that was tested on the same day and in the same gel block as the 125 grain load.

Test Pistol Specs:
Smith & Wesson 686 +  4" Barrel

Testing Protocol:
My testing process is pretty simple.  I take one shot at the end of a Clear Ballistics Gel block that measures approximately 6" x 6" x 16" and weighs approximately 16 lbs.  I take the test shot from 8 feet away and impact velocity is measured less than 2 inches away from the block.  Clear Ballistics Gel is calibrated to 10% ballistics gel density.  I shoot the block at the range and then bring it home to analyze the block and recover the bullet.  Immediately prior to shooting the block, I take a 5 shot velocity test over a ProChrono Digital chronograph.

Test Results:
The test results are summarized in the data sheet below along with a close up shot of the recovered bullet.


Video documentation of the entire test from range through bullet recovery is available below.  The high definition video is best viewed on YouTube, but you can also view it here.

My Thoughts on This Load:

Velocity:
Published velocity for this load is 1235 feet per second when fired in a 4inch test barrel.  Even though the load was tested in a 4 inch barrel, we did not meet the published velocity.  As we saw in the video, that might be a blessing with this load since penetration was excessive and may have been even deeper with another 50 feet per second on top of our tested velocity.

Expansion:
The average expansion of the recovered bullet was .515".  We can turn this into an expansion ratio by dividing the expanded average diameter by the unexpanded bullet diameter of .357".  The result of the math is an expansion ratio of 1.44.  This means the recovered bullet is 44% larger than the unexpanded bullet.  On the surface that expansion ratio doesn't appear to be very impressive, but if you look at the recovered round you will see that expansion was complete and the trademark Gold Dot is clearly visible at the bottom center of the hollow point cavity.

I took a closer look at the 125 grain and 158 grain Gold Dot bullets loaded in these 357 rounds.  Aside from the 158 being longer overall than the 125, the noses of the bullets have very different shapes.  I also think the jacket and lead hardness may different.  The 125 grain petals peeled back all the way to the crimping groove or canalure of the bullet, while the 158 grain petals stopped well short of the canalure.  This difference and the fact we see the "gold dots" on the top of each recovered bullet lead me to believe both the 125 and 158 grain bullets expanded exactly as they were designed to expand. 

Weight Retention:
The recovered bullet from this test weighed 157.9 grains.  We can convert this to a weight retention percentage by dividing the recovered weight by the bullet weight published on the box.  In this case the weight retention percentage was 99.9%.  Weight retention was excellent as we would expect from the Gold Dot bonded bullet.

Penetration:
I'm really glad I decided to add a half block behind the normal 16" block for this test.  As we saw in the recovery portion of the test video, penetration was an incredibly deep 23 inches.  Luckily we caught the bullet in the block and were able to get an exact measurement of the penetration depth.     

Energy:   
As we discussed in the 125 grain review, energy is a calculated value that offers a comparison point from one load to another.  I have noticed that the hollow point rounds carrying the most energy into the block tend to create the largest temporary stretch cavities.  How much permanent damage is caused the temporary stretch cavity is another highly debated topic on the gun forums.  I will say that the wound channel artifacts left in the block showed a smaller, but equally long wound channel as compared to the 125 grain load.

Wrap Up:
I found it very insightful to see what a difference 28 grains of bullet weight can make between the previously tested 125 grain and the 158 grain load featured in this test.  While both bullets share the Gold Dot name, I have to believe they are constructed differently and may even be intended for different purposes.  This load definitely sets the standard for rapid and controlled expansion with very, very deep penetration.    






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.

Saturday, February 2, 2013

Speer Gold Dot .357 Magnum 125 Grain Stress Test

 
This is the first completed stress test using my new stress test barrier in front of the gel block.  The history and complete disclosure of what materials go into the stress test barrier can be found HERE so I won't go into it again in this article.  It was important to me that this load should be the first one tested in the barrier so it could serve as a performance benchmark for all subsequent tests.

The 125 grain .357 Magnum cartridge fired from a 4" revolver has long been the high water mark for effective defensive pistol ammunition.  The 125 grain load must be a "full power" 357 Magnum loaded to levels achieving 1400+ feet per second velocity from a 4" barrel.  Regardless of whose terminal ballistics testing doctrine you subscribe to, there appears to be a loose consensus that for pistol ammunition, the 125 grain .357 Magnum is the most effective fight stopper.  I have no expertise in wound ballistics or human anatomy so I will go along with the opinions of the experts in this area.  

Test Pistol Specs:
Smith & Wesson 686 +  4" Barrel


Testing Protocol:
My testing process is pretty simple.  I take one shot at the end of a Clear Ballistics Gel block that measures approximately 6" x 6" x 16" and weighs approximately 16 lbs.  I take the test shot from 8 feet away and impact velocity is measured less than 2 inches away from the block.  Clear Ballistics Gel is calibrated to 10% ballistics gel density.  I shoot the block at the range and then bring it home to analyze the block and recover the bullet.  Immediately prior to shooting the block, I take a 5 shot velocity test over a ProChrono Digital chronograph.

Stress tests include an additional barrier of 5/6 ounce tooling leather and 2 layers of medium weight denim in front of the gel block.


Test Results:
The test results are summarized in the data sheet below along with a close up shot of the recovered bullet.




Video documentation of the entire test from range through bullet recovery is available below.  The high definition video is best viewed on YouTube, but you can also view it here.


My Thoughts on This Load:
Since we are considering this test our benchmark for stress test terminal performance, let's recap the facts from the test instead of me sharing my thoughts as I usually do.

Velocity:
The test shot registered very low velocity.  I'm going to discard the measurement because I think the barrier panel may have interfered with the chronograph stop sensor.  I've always tried to get chronograph as close to the test block as possible, but I think I need to include some additional space for future tests.  Based on all previous shots, impact velocity should have been 1400+ feet per second.

Expansion:
The average expansion of the recovered bullet was .513".  We can turn this into an expansion ratio by dividing the expanded average diameter by the unexpanded bullet diameter of .357".  The result of the math is an expansion ratio of 1.43.  This means the recovered bullet is 43% larger than the unexpanded bullet. 

Weight Retention:
The recovered bullet from this test weighed 124.5 grains.  We can convert this to a weight retention percentage by dividing the recovered weight by the bullet weight published on the box.  In this case the weight retention percentage was 99.6%. 

Penetration:
The benchmark minimum desired penetration depth, in bare gel, has generally been set at 12 inches.  From various readings on the subject of desired penetration depth for defensive ammunition, any penetration depth between 12 and 16 inches appears to be acceptable.  In our test, the recovered bullet came to rest 18.3125 inches into the gel.

Wrap Up:
Looking back on the bare gel test results HERE and the stress test results above, I'm really starting to see why the 125 grain .357 Magnum running at 1400+ fps has developed such an enviable track record for terminal performance.  It's obvious that the barrier had an impact on bullet expansion, but it did expand.  Weight retention was outstanding with the Gold Dot bonded bullet.  Some may express concern about the 18+ inches of penetration, observed in this test, for fear of over penetration.  I discount those concerns because internal barriers were not accounted for in our test protocol.   
   
This test has set the performance bar at a very high level.  It will be interesting to see how other calibers and bullets perform in the stress test. 




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.