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]

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.