DocGKR - Ballistics Expert

[robmcd]

Some of you may be familiar with Dr. Gary Roberts (DocGKR on many firearm forums). He's a leading expert in ballistics testing. Here's a link to another forum where he discusses defensive handgun ammo. If you go back one notch in that forum, you see much more.

[REACT]

Great link(s). It is this kind of scientific data (as opposed to personal opinion/conjecture) that has changed my mind about .357 SIG & .40 S&W and steered me back to 9mm. (Almost) same hole with less drama.

I now carry 9mm 147 gr JHP bullets and feel comfortable about the decision.

[garyb]

Interesting but I read no mention of the Fed Hydrashock, Corbon DPX, faster 135gr JHP and other newer .40S&W defense rounds...hmmm;...when was this written/printed?

[earle8888]

I certanly agree with the last statemnet on the link. I think the rest has personal preference influence. That said the requirements for LEO's and for that matter, the military handgun, is significantly different that a ccw. The reliablity and proficiciency are required, BUT.

[robmcd]

The following is a brief bio on Dr. Roberts for your consideration. He is the "E.F. Hutton" of wound ballistics:

"Dr. Roberts, LCDR, USNR, is currently on staff at Stanford University Medical Center; this is a large teaching hospital and Level I Trauma center. After completing his residency at Navy Hospital Oakland in 1989 while on active military duty, he studied at the Army Wound Ballistic Research Laboratory at the Letterman Army Institute of Research and became one of the first members of the International Wound Ballistic Association. Since then, he has been tasked with performing military, law enforcement, and privately funded independent wound ballistic testing and analysis. He remains a Navy Reserve officer and has recently served on the Joint Service Wound Ballistic IPT, as well as being a consultant to the Joint FBI-USMC munitions testing program and the TSWG MURG program. He is frequently asked to provide wound ballistic technical assistance to numerous U.S. and allied SOF units and organizations. In addition, he is a technical advisor to the Association of Firearms and Toolmark Examiners, as well as to a variety of Federal, State, and municipal law enforcement agencies. He has been a sworn Reserve Police Officer in the San Francisco Bay Area, where he now he serves in an LE training role."

[Mr. S]

Interesting but I read no mention of the Fed Hydrashock, Corbon DPX, faster 135gr JHP and other newer .40S&W defense rounds...hmmm;...when was this written/printed?

He talks about the Hydrashock(not favorably) in the notes section on the 1st post near the bottom of the first link.
The Corbon DPX is listed under the Barnes XPB(now called Tac-XP) as Barnes makes the copper bullet Corbon uses in the DPX.
Black Hills also loads the Tac-XP(different name same bullet) and it is available in 50 round boxes at a good price compared to DPX.


Here is another link to look at.

http://ammo.ar15.com/project/Self_De..._FAQ/index.htm

[garyb]

You have my attention that this is interesting stuff...seriously. I will read through it all much more carefully to see what I can learn from this material. I'd also like to determine if there have been any ammo changes since this 2006 link was posted or updates since the 1989 FBI document was written. FYI - I am not an expert nor stuck on any one particular round and am willing to make necessary adjustments. I would still like to read more on the newer 40S&W 135gr JHP rounds and the newer Corbon 140 Barnes ammo. If the 135gr is acceptable in the 9mm, why wouldn't it be in the 40S&W? Doesn't this raise a question in your mind? If you find any updated material which includes the 40S&W 135-140gr compared to the slower, heavier 165 or 180gr, please post it. Perhaps as I read the material you posted more carefully, it will be explained. Everything I've read about this shows the faster 135 JHP to be superior in the 40 format. Obvioiusly, the 9mm has also made progress and seems to be gaining more acceptance now that the ammo has been improved upon. Needs more research. Thanks.

[robmcd]

garyb: I like the quotes in your signature area. I use the last one in all of the courses I instruct.

At the botton of Dr. Roberts' post, it shows the last day he updated it was 8-18-2010.

I'm like everyone else. My curiosity is peaked by new, and possibly better ammo. I have to buy a box of everything and try it. Invariably I return to Gold Dot, Federal HST or Winchester SXT. Gold Dot will generally feed well in anything, and offers acceptable expansion and penetration.

[Mr. S]

You have my attention that this is interesting stuff...seriously. I will read through it all much more carefully to see what I can learn from this material. I'd also like to determine if there have been any ammo changes since this 2006 link was posted or updates since the 1989 FBI document was written. FYI - I am not an expert nor stuck on any one particular round and am willing to make necessary adjustments. I would still like to read more on the newer 40S&W 135gr JHP rounds and the newer Corbon 140 Barnes ammo. If the 135gr is acceptable in the 9mm, why wouldn't it be in the 40S&W? Doesn't this raise a question in your mind? If you find any updated material which includes the 40S&W 135-140gr compared to the slower, heavier 165 or 180gr, please post it. Perhaps as I read the material you posted more carefully, it will be explained. Everything I've read about this shows the faster 135 JHP to be superior in the 40 format. Obvioiusly, the 9mm has also made progress and seems to be gaining more acceptance now that the ammo has been improved upon. Needs more research. Thanks.

The link I posted was updated in 2010.
Read through it.Here's a few quick comparisons

.40 SW 140 DPX VS 180 HST Corbon 140gr DPX


9mm 115+P DPX VS 147 HST

Corbon DPX 9mm vs

[garyb]

Changed My Way of Thinking

I've carefully read through the material and have changed my way of thinking about a few things. It was good stuff, particularly the Handgun Wounding Factors paper. The link seemed to be lacking on ammo comparisons and I would have liked to see more ammo covered, but realize/admit it is difficult to cover it all. Specifically to see the Corbon 135 JHP as mentioned below.

Anyway, I originally selected Fed hydrashock 135 feeling this particular round had adequate penetration yet might limit over penetration and collateral damage to innocent bystanders. I learned that this concern is an over exaggerated one, as discussed clearly in the report. The rationale is there and I understand it. The words "too little penetration will get you killed" rang clear to me and I understand it even in civilian situations. I have changed my way of thinking on penetration in civilian situations and earle8888 tried to point this out to me previously. He was correct and I was wrong. Earle8888 I hope you read this.

The paper also changed my thoughts on temporary cavity (to some degree -although I have seen in deer that I've shot that surrounding tissue does get damaged with major brusing/internal bleeding). It changed my thoughts on shock and the myth of knock down power. It's penetration of at least 12" that is needed and the edge always goes to the bigger bullet.

I would like to learn more about velocity and penetration. Specifically, I am interested in the Corbon 135 JHP due to it's velocity. If anyone has any data on the penetration of this ammo, say compared to the Corbon 140 DPX and the Win Ranger 135 and 155; I would love to see it. Please pass it along.

I am not immediately going out and buying new carry ammo to replace my Fed hydrashock 135. I am going to do some more research and focus in on some new ammo for my next purchase - something with more penetration and that I can shoot well in my PM40. I already know the Corbon 140 DPX will do the job, but perhaps there is something better to suit me.

Hey guys, thanks for helping me to think differently :7:about some of these important topics. Clearly, we all need to be open to learn, change and not be so stuck in our ways. Much appreciated.

[robmcd]

garyb - like you, I carried CorBon 135 gr JHP for a few years, then I started to experiment a bit. I've been searching for test date, as I'm sure that DocGKR has tested just abiut everythng. I did, however, find the following test data on a post from DocGKR which includes 40 S&W 135 gr. PowerBall vs. 180 gr. HST. When PowerBall first came out, I switched to it during the winter months thinking it would better penetrate heavy clothing, and also thought it would better survive a trip through auto glass enroute to a car jacker.

I'll try to e-mail DocGKR today for info on the 135 gr JHP:


Let's review the critical data differences between Powerball and HST when compared using the same proven test methodology:

9 mm Corbon 100 gr +P PowerBall 1555 f/s from G17
BG: pen=10.9”, RD=0.60”, RW=93.9gr
4 layer denim: pen=11.4”, RD=0.58”, RW=97.5gr
The mighty 4.7” of pen after the auto windshield was not comforting…

9mm Fed 147 gr JHP HST (P9HST2) from G17:
BG: vel=1037f/s, pen=11.9”, RD=0.64”, RW=147.8gr
4 layer denim: vel=1049f/s, pen=14.7”, RD=0.54”, RW=147.5gr
auto windshield: vel=1042 f/s, pen=13.4”, RD=0.53”, RW=140.4gr

.40 S&W Corbon 135 gr Powerball from S&W 4006
BG: vel=1362 f/s, pen=11.6”, RD=0.65”, RW=131.4gr
4 layer denim: vel=1359 f/s, pen=12.1”, RD=0.65”, RW=131.9gr
auto windshield: vel=1365 f/s, pen=7.9”, RD=0.61”, RW=103.6gr

.40 S&W Fed 180 gr JHP HST (P40HST1) from S&W 4006
BG: vel=960 f/s, pen=12.6”, RD=0.65”, RW=181.1gr
4 layer denim: vel=961 f/s, pen=15.6”, RD=0.62, 181.3 gr
auto windshield: vel=904 f/s, pen=15.2”, RD=0.47”, RW=180.4gr

.45 ACP Corbon 165 gr +P Powerball from 1911
BG: vel=1230 f/s, pen=12.1”, RD=0.70”, RW=158.8gr
4 layer denim: vel=1267 f/s, pen=11.8”, RD=0.66”, RW=159.7gr
auto windshield: vel=1251 f/s, pen=5.5”, RD=0.73”, RW=143.5gr

.45 ACP Fed 230 gr +P JHP HST (P45HST1) from 1911
BG: vel=926 f/s, pen=12.6”, RD=0.74”, RW=231.8gr
4 layer denim: vel=915 f/s, pen=15.4”, RD=0.67, 231.1 gr
auto windshield: vel=918 f/s, pen=19.7”, RD=0.54”, RW=228.6gr

[garyb]

Interesting what happens when you change your thoughts on something. Now I'm starting to lean away from the lighter 135's in the 40cal, as I've learned that velocity and power isn't everything. Perhaps penetration, size & expansion, and momentum (mass X velocity) are more important considerations. Trying to find something that feels more like my target/practice ammo Win 165 FMJ. I am interested in the Speer Gold Dot 155 JHP where www.firearmstactical.com shows it to have 13" gel penetration with expansion to .64"; and 16" denim pen with exp to .60"
It is comparable to Corbon 140 DPX with 12.6 gel pen and .64 exp; and 11.5" denim exp with .64" exp. Corbon DPX was designed around the Kahr, but a slight edge (and better price) goes to Gold Dot 155. I know some guys have said that price should not matter in defense ammo, but the reality is that if you can find something equal or better and at a better price, why spend more. Both seem to be very good choices and meet the criteria, based on all the ballistic and penetration data I have read thus far. However, I'd need to shoot both together to determine which I preferred through my PM40...accuracy and feel are just as important. Still researching...... Maybe even the Hornady 155 XTP JHP or the Federal 155 HST???? Good dialog and info.

[robmcd]

garyb - Coming from CorBon 135's myself, I lean toward the 155 gr. Gold Dot or Tactical HST because they seem to offer the best blend of muzzle velocity, muzzle energy and wound ballistics. Another feature that I like is the nickel plated cases and sealed primers. The Tactical HST probably has a slight edge due to sharp edges when expanded, but the profile of the Gold Dot is more conducive to positive feeding.

Gold Dot 155 gr = 1200 fps, 496 ft-lbs.
LE Tactical HST 155 gr = 1160 fps, 463 ft-lbs.

Gold Dot 180 gr = 1025 fps, 420 ft-lbs.
LE Tactical HST 180 gr = 1010 fps, 408 ft-lbs.

When students ask me what kind of gun, ammo, etc they should buy, my answer is always the same - reliable. I guess that reliability is subjective, as it's often tied to our specific application and personal opinions. I know that applies to me. Uh-oh, I just found out that Speer offers an LE Gold Dot 200 gr in .40 S&W. I need a box!

By the way, www.ammunitiontogo.com usually has both the Gold Dot and HST in stock in 50-round boxes.

Happy Holidays to everyone on the forum.

[earle8888]

Wish somebody had empirical data on reaction when different type and weight bullets hit BONE. I have personal experience with deer, elk, antelope, bear and others. A soft point bullet usually terminates it penetration and depending on energy, breaks bone and drives it farther. my experience also suggest, that a compound fracture or complete breakage of a larger bone brings the ]most effective stopping of the animal. Therefore I believe that the heavyest, fastest, FMJ, Truncated bullet, that is also one that promotes the best shot placement, is the one for me! That said, not only do trucated cone FMJ penetrate windshields and most other obsticles, BUT, if a bone is not struck will normally exit with potential for damage to others!

[garyb]

earle888, I wonder what the expansion of that FMJ would be compared to a JHP or Barnes expander type? I am comparing penetration and expansion characteristics (with sharp tearing edges), as they both equate to tissue damage and I honestly don't have the comparisons with FMJ. I agree with your comments on bone. Sometimes I purposely take a deer through the front shoulders, so they don't make the mad dash to bordering property, etc.......They go down and stay down. However, the shoulders get destroyed, so sometimes I simply take them through the chest/heart/lungs and have a little track job (<100yrds). A good bone hit puts them down. However, on humans and in an emergent situation under stress, other than a head shot (for which any ammo will work fine), I can't see bone being a calculated opportunity. It could just happen by chance, but focus on center mass, the ribs and sternum are not really the same deal. Perhaps the hips and groin in very close combat, but why take the chance when center mass is a larger target. I'm interested in your thoughts. By the way, you were absolutely correct about the penetration issue...I admit that I was wrong with my original selection of 135gr ammo as I incorrectly focused primarily on velocity and wanted to avoid over penetration and the risk of collateral damage. Penetration is important...you were correct.

I am starting to focus on Corbons 140 DPX, Gold Dot 155 JHP, or 155 Tactical HST. I saw some good videos of the Corbons that were convincing and they are worth the extra cost. Claims are that Corbons will penetrate auto glass, doors, plywood, etc... and the expansion and tear edges are good. Corbon told me they were designed for short light guns like the Kahr. I am starting to appreciate them more and more. Each of these seem to meet the penetration and expansion criteria. For some strange reason, I am just not wanting heavy carry ammo.
This ammo selection stuff must be way too over rated. I read in another forum where one guy felt that defense ammo was all good and to quit quibbling over it and just focus on shooting better...shot placement. He makes a good point to some degree. I guess we are all looking for that extra 1% edge should it be needed.