Hornady Critical Duty 9mm Velocity Testing

In a recent range session, I used my LabRadar to measure the velocity difference between barrel lengths for the Hornady Critical Duty 9mm 135 grain FlexLock standard pressure round. For the testing I used my SIG P365, my SIG P320 Carry, and my P320 X5 Full size pistols.  

Since I use this Hornady Critical Duty 9mm round in my SIG P320 Carry and my P365 everyday carry pistols, I was curious about the velocity difference between barrel lengths. My expectation going into the testing was that the P365 would record the lowest velocities and the X5 would record the highest velocities since it had a longer barrel.

However, that was not the case. The P320 Carry with its 3.9-inch barrel recorded the highest velocities. I fired ten rounds of the same lot number through each of the three pistols. The table below shows the results of my testing with the velocities in feet per second or FPS. 

Pistol	Barrel	Average	High	Low	Extreme Spread	Std Deviation
SIG P365	3.1 Inches	959	975	943	33	14.8
P320 Compact Carry	3.9 Inches	1038	1048	1019	29	13
P320 X5	5.0 inches	983	1010	974	37	15.3

 

I referenced the Lucky Gunner Handgun Self-Defense Ammunition Ballistics Test and looked at their results for the standard pressure Critical Duty round. In their 9mm Luger testing, Lucky Gunner used a Smith & Wesson M&P9C, 3.5-inch barrel—a barrel exactly halfway between the barrel lengths I used. The Lucky Gunner average velocity for five shots from the 3.5-inch barrel was 1053 FPS.

Hornady’s description of the Critical Duty states in part that it is: “Designed to meet the needs of those who demand superior barrier penetration and prefer a full‑size handgun for their personal protection.” To me, full-sized would mean a five-inch barrel. However, Hornady’s ballistics data for the Critical Duty 9mm 135 grain standard pressure round showed a velocity of 1010 FPS from a four-inch barrel.

So why was the velocity lower in the five-inch X5 barrel when compared to the 3.9-inch P320 Carry? I have no idea. Perhaps the burn rate for the powder Hornady uses is optimized for a four-inch barrel. I can speculate that the extra 1.1 inches adds a bit of drag to the bullet because the powder had burned at the 3.9-4.0 inch mark. However, that is pure speculation.

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* Lucky Gunner Labs did some interesting ballistics gel testing.  I recommend their research: https://www.luckygunner.com/labs/self-defense-ammo-ballistic-tests/#9mm

Shot in the Back! Justified or Not?

Prosecutors have criminally charged police officers when the officer has shot someone in the back or when the officer shot someone falling down, stating that these shots were unjustified. There is a fine line between shots that are a lawful response to a deadly threat and shots that are fired after the deadly threat ceases. The only time a private citizen defender (or law enforcement officer for that matter) may use lawful deadly force is when another is threatening or using unlawful deadly force. When the threat has ended, the defender must stop using deadly force. Of course, the problem lies in determining exactly when the threat has ended. The fact that basic human nature often causes an attacker to reflexively turn away from the defender’s gun compounds the difficulty of making this determination.

Dynamic, deadly encounters can happen very quickly and a private citizen’s use of deadly force in lawful self defense can be over in moments. However, close legal scrutiny on the defender’s decision to start and stop shooting can result in the aftermath taking years to play out. 

Massad Ayoob cites an example of this challenge in the case of Florida v. Mary Hopkin in the mid-1980s. Mary Hopkin was a frequent victim of her burly common-law husband James Yarolem who often beat her and once had strangled her and left her for dead. Yarolem was out on bail and drunk when he returned to Hopkin’s home and tried to enter. Hopkin wouldn’t let him in and warned him that she had a gun; however, he broke down the door and advanced on her.

Hopkin fired three shots as fast as she could from a .22 LR revolver and stopped shooting when she perceived Yarolem to turn and run. He collapsed and died outside; however, Hopkin’s shots had hit him once in the chest, once in the side just behind lateral midline, and a fatal shot square in the back and into his heart. Janet Reno charged her with murder because she shot Yarolem in the back when he was “no longer a threat.” However, the jury found her not guilty after her attorney Mark Seiden, deconstructed the state’s case meticulously point by point with Massad Ayoob’s assistance.

Exactly how fast can someone turn around? Professor Bill Lewinski of the Force Science Institute at the University of Minnesota at Mankato found that a person could turn from facing forward to exposing their lateral mid-line in ¼ second for ¼ turn and ½ second for ½ turn--in other words fully presenting their back in 0.50 seconds. Further, there are cases where a shooter facing away can effectively point their pistol behind them (Lewinski, B., (2000)).

The Tadarius Hunt Incident:

In the images below, Tadarius Hunt, a suspect wanted for attempted murder points his pistol backward and fires at a police officer as he is running in the opposite direction. We see two different versions of the incident – one from police vehicle dashcam and one from the officer’s perspective. In the picture Back #1 below, Hunt has drawn a pistol and is firing it at the officer.

Back #1 Hunt has drawn a pistol and is firing it at the officer

In the picture Back #2 below, Hunt has turned to his right and is pointing the pistol at the officer as he prepares to fire once again.

Back #2: Tadarius Hunt Pointing A Pistol At Police Officer

In the picture Back #3 below, Hunt has turned further to his right and is firing the pistol at the officer once again.

Back #3: Hunt Firing at the Police Officer

Every time the Hunt pointed his pistol at the police officer, his back was exposed. It is likely that without the video evidence, it would have been easy for an emergency room physician or a prosecutor to conclude that the officer shot Hunt in the back as he was fleeing.

The Force Science Research Center (FSRC) has done research to understand the stop shooting problem when a police officer is shooting and assessing and has identified several factors explaining why a police officer who is both shooting and assessing cannot stop shooting immediately. This is the exact same problem a private citizen defender faces.

John Farnam did a study of just how fast someone could fire a revolver and found that it could be fired four times a second, while a semiauto could be fired five or possibly six times a second. My personal testing shows that someone with intermediate to advanced skills could fire a revolver five to six times a second and a semi as many as six to eight shots in a second. Of course, adrenaline, firearm design, and personal skill can affect this speed. Jerry Miculek holds the current record for shooting eight shots from a revolver on a single target in 0.94 seconds or one shot every 0.117 seconds (not counting his reaction time to the timer signal).

In the Tempe Study (2003), the FSRC determined that the typical reaction time to an anticipated stimulus is 0.25 seconds. From a stopping perspective, the study showed that when the average police officer stops shooting based solely on a perception of change in the outside world (and was anticipating this change), the fastest the officer is able to do this is 35/100ths of a second resulting in two shots being fired (p. 28). The ability to stop will occur not when the subject has changed their threatening behavior but after the police officer begins to detect a change in the threatening behavior. This distinction is important because the psychological processes of perception and detection often take many times longer than the physical responses involved.

The FSRC concluded that an officer who engages sequentially in all of the steps necessary to cycle through the observe, orient, decide act process can take a second to a second and a half or more to stop shooting. Measured in trigger pulls, which are occurring at a quarter of a second each, this is an extra four to six rounds after the threat stops. 

This is approximately the same amount of time that Green (2000) found for reactions to applying the brake and stopping in a real-world driving situation. This means that it is not possible to stop shooting at an attacker before he/she has an opportunity to spin and receive shots to the back (see also Lewinski, B., (2000)).

What are the implications for the armed citizen? If you are committed to firing a shot and have started to pull the trigger, the speed with which you can pull the trigger likely precludes stopping that action. If the threat turns as you pull the trigger, the trigger pull speed when combined with turning speed (particularly the speed of a young, athletic person) could easily result in justifiably firing one or more rounds that impact the threat in the back.

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Ph.D. Lewinski, B., (2000) Why Is The Suspect Shot In The Back? Finally, Hard Data on How Fast the Suspect Can Be In Eleven Different Shooting Scenarios

Ph.D. Lewinski, B., & Hudson, B. (2003a). Time to start shooting? Time to stop shooting? The Tempe study. The Police Marksman, 28(5), 26-29.

Green, M. (2000). “How long does it take to stop?” Methodological analysis of driver perception-brake times. Transportation Human Factors, 2(3), 195-216.

Fourteen Inches -- Is an NFA Shotgun Worth the Effort?

In today’s world of tacticool and combat hype, is purchasing an NFA shotgun worth the time and money when you can buy a short barreled, pistol-grip firearm that is “not a shotgun” such as the Remington Model 870 TAC-14? I think the answer to this question is yes.

VCS 965 NFA Short Barreled Shotgun

I recently purchased a Vang Comp Systems (VCS) 965 Shotgun. The VCS 965 is a highly modified Remington 870 pump shotgun with a 14-inch ventilated rib barrel which makes it an NFA-regulated short-barreled shotgun (see more information on the National Firearms Act below).* The key difference from a regulatory perspective is the stock on the 965. The stock on the 965 makes it an NFA shotgun whereas the pistol grip on the TAC-14 means it is not a shotgun even though it fires 12-gauge shotgun shells. Confusing right? But that is the nature of firearms regulation in the U.S.

 

Modified Remington TAC-14 Firearm

So why bother with an NFA shotgun if you can buy a TAC-14, a Mossberg Shockwave, or similar non-shotgun? The VCS 965 NFA shotgun is only 6-1/2 inches longer than the TAC-14; however, the stock makes a big difference in how it handles and shoots. Getting accurate hits with the 965 is no different than getting hits with a standard eighteen-inch shotgun. However, the 965 is much easier to maneuver in tight spaces such as a building or vehicle. I have some experience with the TAC-14 and similar firearms can attest that accurately shooting these firearms with a pistol grip requires a fair amount of upper body strength and proper technique. If you are an experienced shooter, getting your hits with these firearms is not impossible as Hickok45 demonstrated in a video of the TAC-14 (see link below).

So how does the shorter barrel perform? I did some testing to determine the difference in pattern between an 870 with an eighteen-inch barrel and the fourteen-inch 965 barrel. Both guns have the VCS port modifications and I used Federal Power-Shok 2-3/4" 8 Pellet 000 Buckshot ammunition for testing. I shot five shells from each gun at ten yards. The 870 with an eighteen-inch barrel patterned five inches and the 965 patterned 6-3/4 inches – a negligible 1-3/4-inch difference.

Is an NFA Shotgun Worth the Effort? I think so. The advantages that the shorter barrel and stock provide and the fact that the performance differences between the short barrels and a standard eighteen-inch is negligible makes it worth the effort to acquire an NFA SBS. All in all, I am pleased with the VCS 965’s performance and look forward to putting it through its paces during a shotgun match.

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* The National Firearms Act regulates the registration, possession, and transportation of a variety of firearms and devices. Further, each state’s laws dictate what can or cannot be possessed, with some counties within states having different regulations as well. Please contact your local ATF Field Office with any NFA questions or concerns.

Hickok45 Video: https://www.youtube.com/watch?v=SbV0T_hWyNA 

Additional Note: I have some anecdotal experience with 14-inch shotguns. In the early 1980’s, I was fortunate enough to have access to the State Department’s Diplomatic Security Service (DSS) firearms research at Quantico, Virginia. At that time, the DSS was trying to identify the shortest functional length of a shotgun barrel when firing the standard magnum 12-pellet 00 buckshot load. The DSS goal was to identify the buckshot load’s peak dwell versus velocity and cut the barrels to that length. Said another way, the DSS wanted to have the shortest possible barrel without losing any velocity. (Peak dwell defined as the instant the powder completes burning as the shot column is moving down the bore.)

DSS researchers determined that thirteen inches was the optimum dwell/velocity point and cut Remington 870 barrels to that length for testing. A problem immediately surfaced. When the peak dwell/velocity point was at the barrel muzzle, the barrels were splitting. It turned out that the muzzle was also the barrel’s weakest point on the shotguns of that era. However, barrels cut to fourteen inches worked just fine and did not split. I believe that the common fourteen inch standard we see today likely resulted from the DSS research. As an aside, the Vang Comp experts said that the optimum dwell/velocity point with modern powders is about eight inches.