In God we trust. Everybody else must bring data.

One of my nephews is very fond of handguns.  He realizes that the human-skills portion is the most perishable link in the chain and is, therefore, the most likely point of failure.

To address that, he began casting about to find less expensive ways to shoot...and then he remembered that Uncle Joe reloads ammo.

He picked an economy, 165 grain, jacketed hollow point for his compact 40 S&W.  I made the executive decision to start with Hodgdon's Titegroup powder.  One reason is that I had a pound of it sitting on my reloading bench.  The other reason is that Titegroup is a very efficient powder.  It has a high energy content (read, high percentage of nitroglycerine) and produces high velocities with relatively small amounts of powder.

Muzzle blast is an issue with shorter barreled pistols.  The sensation of "recoil" is at least partially due to muzzle blast.  Another issue is muzzle flash in low light conditions.  It can be distracting or even blinding to the shooter.  Both blast and flash are made worse by high powder loadings.

Three smokeless powders.  Note:  The bullet my nephew chose was not a Sierra but this data is the closest I could find to his choice.

Compared to Hodgdon's Titegroup, Hodgdon's Longshot uses 53% more powder (by weight) to produce 13% more velocity.  Hodgdon's CFE Pistol uses 33% more powder to produce 10% more velocity.

Following good reloading practice I made ten rounds at the starting load and ten at the maximum load.  They cycled my nephew's handgun just fine.

The problem
The problem was when we shot them into the water trap.

My nephew's plan is to use the same ammo for practice and for every day carry.  That is a fantastic plan because shooting 1000 rounds through his handgun will validate its reliability.  (Note, many people I respect claim that 200 rounds without a bobble is the minimum threshold of "carry" reliability.  At a buck a round that is pricy...especially if the first few you try don't pass the test.)

He quite realistically expects the hollow points to expand.  And the bullets he chose were not going fast enough when pushed by 5.1 grains of Hodgdon's Titegroup to do that.  They plowed through the entire length of the water trap and buried themselves into the wood barrier at the far end.

And that is why we test things.  Theory provides a good starting point and can guide our decisions but results trump theory. 

Note that we did not shoot this over a chronograph.  He does not need to know how fast it is going.  For his peace of mind, he needs proof (data) that it will expand when it gets there.

One question that he asked was "How does water compare to human flesh?"  My response was "Which human flesh?"  Water is about equal to the human liver.  It is more dense than lung tissue but less dense than muscle (heart, thighs) and much less dense than bone.  The ribs are smaller and have less "bony" material than most folks imagine.  So my figuring is that a water trap is a decent compromise for shots that enter the front of the thoracic cavity.  And it is WAY better than guessing.

My next step is to buy a pound of Hodgdon's CFE Pistol and see if another 100 feet per second (20% more energy) can get this bullet to expand.  If that does not do the trick then my nephew needs to pick another bullet, perhaps one of a lighter weight, if he wants reliable expansion out of his compact handgun.