Food for Thought – Defensive Handgun Bullet Weight

Folks get all tied in knots when it comes to defensive handgun ammunition. One guy will say something about carrying 185 grain loads in his .45 and another will call him a fool and claim anything less than 230 grains is like shooting a 9mm. Then, the guy will probably start bashing the 9mm.

The truth is really a very simple thing. All standard pressure .45 Auto loads have the potential to do the same amount of work. Why? They operate at the same pressure and pressure is what pushes the bullet, regardless of its weight, out of the barrel.

For example, standard .45 Auto – regardless of bullet weight – have a maximum operating pressure (MAP) of 21,000 psi. MAP +P loads is 23,000. The velocity at which the bullets exit the barrel is based on the pressure and the bullet’s weight. Heavy bullets come out slow, light bullets come out fast.

Heavier bullets generally penetrate deeper because of their weight and lack of expansion; the slower a bullet is moving, the harder it is to get it to expand. To illustrate this, I compared the terminal performance test results from 18 different .45 Auto loads with bullets ranging in weight from 160 to 230 grain. Below are the average results for velocity, penetration, expansion and crush cavity size. The crush cavity size was computed as you would determine the volume of a cylinder based on bullet diameter and depth of penetration. Expansion is shown as a percentage of original bullet diameter.

Bullet Weight    Velocity          Penetration       Expansion          Crush Cavity   Rec. Weight

(grains)               (fps)                    (inches)                             (%)                       (cu.in.)                (%)

160-165gr           1091                    11.3                     57.45                   4.4                       85.96

HIGHEST             1264                    14                        72.57                   5.1                       100.00

185                      1010                    12.5                     62.61                   5.2                       95.95

HIGHEST             1144                    17                        85.84                   6.2                       100.00

200-230              889                      15.6                     48.57                   5.5                       89.63

HIGHEST             955                      17.25                   61.50                   6.3                       100.00

NOTE: This table shows the average performance of each bullet weight. It also shows the highest recorded number for each bullet weight. Keep in mind that the highest recorded numbers are, in every case, from different loads. They do not represent an individual load.

A number of things can be taken from this other than the obvious fact that on average, heavier bullets go slower and expand less. For instance, notice that the deepest penetrating 160-165 grain bullet drives almost as deep as the average 230 grain load. The widest expanding 160-165 grain load exceeds the average for the 185 grain loads and even the widest expanding 230 grain load.

185 gr. .45 Auto loads often offer the best balance between expansion and penetration. Lighter bullets can also expand well and penetrate almost as deep while heavier bullets really only offer an advantage in penetration.

As for wound cavity size, it is very difficult to measure tissue damage in 10% gelatin. However, it is easy to compute the size of the crush cavity. It is nothing more than the volume of the cylindrical hole made by the bullet, based on its expanded diameter and the depth it penetrates. Clearly, deeper penetrating bullets have larger crush cavities due to the increased length of this cylinder. But, it is of no use to measure the crush cavity that is created beyond the thickness of a bad guy.

If we were to assume that the FBI’s minimum of 12 inches of penetration was the maximum depth of crush cavity to be considered, our numbers would look very different. This shows that on average, 185 grain bullets have an advantage in crush cavity size if penetration beyond 12 inches is discounted. Why? They expand more.

Bullet Weight    AVG Penetration Depth               AVG Crush Cavity Volume

160-165                            10.9                                                 4.4

185                                    11.4                                                 4.8

200-230                            12.0+                                               4.3

Bullet construction and velocity are critical to terminal performance. Sometimes it can be hard to get the heavier 230 grain loads to expand, even from five inch guns.

Essentially, these differences in terminal performance are nothing more than a reflection on how lighter; faster bullets tend to shed energy sooner after impact. Of course, this is really based on how they are constructed, which, combined with velocity is the true determining factor in terminal performance. By shedding energy faster, the bullet creates a larger stretch cavity or damage beyond the crush cavity. This of course is the damage that is very difficult to measure in ordnance gelatin. So, for what it’s worth, let’s compare some of the highest kinetic energies of actual loads.

 

 

Bullet Weight                   AVG Velocity     AVG Energy

160                                     1248                    553

165                                     1264                    585

185                                     1144                    537

200                                     955                      404

230                                     889                      438

What does this tell us? It tells us that the lighter, faster bullets have the potential to transfer more energy. No, no, this can’t be right! Heavier bullets are better. You have to look at momentum instead. Right? OK. Let’s do that by multiplying the bullet weight, in pounds, by the velocity.

Bullet Weight                   AVG Velocity     Momentum

160                                     1248                    28

165                                     1264                    29

185                                     1144                    30

200                                     955                      27

230                                     889                      29

If penetration is what you want, consider a hard cast load like this one from Buffalo Bore. You'll have trouble finding something to stop this bullet.

Guess what? For all practical purposes, the loads are all the same. This is a lot of math and a lot of crap just to illustrate a single point. Bullet weight by itself means nothing. Terminal performance and a .45 Auto bullet’s ability to adversely affect a living target come down to two main points; shot placement and bullet design. A .45 Auto FMJ load will penetrate like the devil; over three feet in 10% ordnance gelatin. It will not expand and it makes very narrow wound cavity. On the other hand, Corbon’s 165 grain JHP +P load will only drive to about 10 inches but it will expand an amazing 72% and substantially damage the inside of a gelatin block.

For what it’s worth, look how well Speer’s 9mm 124 grain +P Gold Dot bullet compares to the average 185 gr. .45 Auto load. How could the much smaller bullet from the 9mm compare so favorably with the .45? It is well designed, it is pushed by much more – more than 75% more – pressure and it expands to double diameter. 9mm +P ammo operates at 38,500 psi.

Bullet Weight                   VEL        PEN       EXP                      CC          RW               Energy         M

.45 Auto 185gr.               1010      12.5       62.61%                5.2         95.95%               419        26

9mm 124 gr. +P               1182      13.25    100.00%             5.3         100.00%              385        20

Don't underestimate the 9mm. Certain loads are very effective and can compete with any defensive handgun cartridge.

My suggestion is to quit arguing about bullet weight. Instead, consider picking a defensive handgun load for your pistol by selecting those that penetrate to the minimum depth you desire. Choose the one that expands the most and is 100% reliable in your pistol. Then, dare the bad guy you shoot to tell you how much the bullet weighed or what caliber it was. If he can, you can be sure of one thing; you shot him in the wrong place!

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About gunwriter

Born and raised in the West Virginia hills, Richard literally grew up in the woods. He has chased coon hounds until daylight, waited out whitetails perched high in an oak, canoed the New River and hunted from the Montana Mountains to the Green Hills of Africa. During service in the Army and later as a municipal police officer and Special Agent with the railroad police, Richard obtained numerous certifications in small arms instruction. He has trained military personnel, law enforcement officers and civilians in the application of firearms for defensive, competitive and recreational use. Richard won the West Virginia Governor’s Twenty Award for law enforcement, the West Virginia National Guard State Pistol Competition and earned his Distinguished Medal with pistol. Badge turned in, Richard is now a contributing editor for several magazines. He was the compiling author of the book, Rifle Bullets for the Hunter and conceptualized and contributed to Selecting and Ordering a Custom Hunting Rifle. Richard also contributed a chapter to the John Velke book, The True Story of the Baldwin-Felts Detective Agency. Richard has patents on a riflescope reticle and a revolutionary bullet testing media. A hillbilly at heart, Richard lives on Shadowland - his shooting range in West Virginia - with the most understanding wife in the world, their three kids and a very protective ridgeback hound.
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7 Responses to Food for Thought – Defensive Handgun Bullet Weight

  1. RG says:

    Thanks so much for the excellent info Richard!

  2. mhay says:

    Well written information.

  3. Patrick Mann says:

    I don’t wish to come across as overly critical, but while this piece presents a nice premise, it leaves me with many questions. Were these tests performed in bare testing media? No clothing, car door, sheetrock, cinder block, auto glass, sofa (stuffing and upholstery), bone, or other real-world obstacles? It seems like the above results are predicated on a shot failing to encounter anything except skin, muscle, and organ. Since most bad guys don’t commit their crimes naked and they have skeletal structure which may be between the bullet and a vital spot, it seems germane to a discussion of the merits of defensive handgun bullets to at least include clothing and bone.

    If a bullet hits a rib (glancing or straight-on), is one weight deflected less than another? How about if someone is shooting from a Weaver position and the only way to get a bullet to his vitals is with a shot through the forearm or bicep? Is one bullet weight superior because maybe it doesn’t expand as rapidly and slow down so much that after leaving the arm it fails to penetrate deeply enough in the torso to secure a stop?

    After having shot many living critters- ranging in size from little prairie poodles to good sized goats and up to huge Piney Woods Rooters- with common defensive calibers, I have developed strong opinions on bullet weight and design in each caliber. While my choices aren’t always the heaviest-for-caliber bullets, they are never the lightest.

    • RG says:

      I would like to read the reply to this

    • gunwriter says:

      Patrick,
      No worries about being critical, what I presented was not bible verse. To answer your questions; The tests were performed in 10% ordnance gelatin without intermediate barriers. It was not a media chosen because it best represents a human attacker but because it provides a consistent testing platform.

      When it comes to clothing and bone, most of the modern defensive handgun bullets handle both very well regardless of weight. That is indeed another topic but it is a valid one. As for a thoracic cavity shot, you have about a 100% chance of hitting cloth and a 50% chance of hitting bone (rib).

      Overall, based on the testing I have done, the lighter weight, high velocity bullets tend to be better at expansion after passing through cloth due to the fact that the retained velocity is higher – AND – velocity drives expansion. Bullets that start out going slow have a much smaller window of velocity to expand within.

      Your points are all valid and deserve consideration. In the future and in my upcoming book, many of these will be addressed. The main point I was trying to get across is that
      bullet weight alone is not a reliable means to judge the terminal performance of a defensive handgun load.

      Due to the difference in bullet construction, there are no hard and fast rules when it comes to comparing terminal performance. However, it has been my experience that the best balance of performance with any cartridge (rifle or pistol) is usually found with mid-weight projectiles. Of course, some folks do not want balance.

      • Patrick Mann says:

        Thanks for the reply. It’s refreshing to post something on the “interwebz” and not get shot down immediately. Sounds like you have a good grasp of things and look forward to reading your future contributions.

        I completely agree that some folks don’t want balance. Many individuals I know and correspond with on various forums fixate on energy as the be-all end-all. Others espouse the virtues of homogenous bullets. Some insist that anything less than the heaviest-for-caliber projectile is equivalent to throwing cotton balls at an attacker. Very very few of them have invested the time and effort to actually try their “ultimate stopper” on anything but paper or soda cans. If they do, they would realize that a foot-pound (at least not at the level dished out by a handgun) never stopped or killed anything, some copper bullets are horribly inconsistent and unreliable penetrators, and while heavy bullets virtually guarantee penetration, they can actually cause issues with reliability in some firearms (pulled bullets due to inertia in lightweight handguns) and may not expand reliably from short carry-length barrels due to reduced velocities.

        Heck, with the advent of newer propellents and bullet design and manufacturing processes, it is virtually impossible to make a well-informed decision today that will still be the best choice in a year. For that reason, it is good that there are folks like you who are willing to put in the time and research needed to help get people past the rhetoric and outrageous advertising claims.

        Thanks again, Richard!

      • RG says:

        “contributions…”? Who’s contributing what to what? Who’s blog is this anyway?

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