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.
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
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
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
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!