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Sunday, 16 April 2017

Stopping Power etc. Part 2:

I tried to start a further conversation about "stopping power" and 'Caliber Effectiveness' in the previous post .. and it seems to have worked -  as commenter Colpepper responded nicely (go to comments at the bottom of that earlier page).

In part he adds this thoughtful after-note:

We would respectfully suggest a couple of further points worthy of consideration in any discussion on 'stopping power', bullet expansion, penetration and effective terminal energy. 


While as you note, expansion naturally makes a SMALL CALIBER projectile larger in diameter and modern expanding projectiles make the smaller calibers more effective than ever, the same is obviously equally true of larger calibers.

The second and most frequently neglected point is simply one of MASS and MOMENTUM. The greater the mass / weight the greater the momentum. Assuming near equal velocities, a heavier projectile of similar form will inevitably penetrate deeper.

Naturally, this is also the reason why it is necessary to use larger shot sizes in any shotshell to achieve greater penetration and distance.

In comparing for example a 9mm 115 grain projectile to a .45 230 grain projectile, the 9mm 115 grain pill must be moving at around 1600+ fps in order to approximate the effect of a .45 230 grain projectile moving at 950 fps.

One could hypothesize (incorrectly) that the 9mm 115 grain projectile being only half the weight of the .45 230 grain projectile should be moving at twice the velocity of the .45 projectile in order to approximate the same terminal effect, however the natural laws of ballistics state it doesn't work quite like that.

Doubling projectile weight doubles hypothetical energy, while doubling velocity quadruples hypothetical energy.

Note, we use the term "hypothetical energy" which does NOT necessarily approximate "effective" terminal energy. 


I fully accept that a large diameter bullet may expand to the same degree as a smaller one will - both ending-up say twice as big as they started ... So, I think the sentiment here is to make the point again that a bigger, more powerful projectile will likely be more effective and certain in it's performance than a lesser example..

And I can't disagree with that premise - as it is theoretically correct. - BUT - it does seem that some lesser cartridges are fully as capable - and are factually recorded as indeed having superior levels of effectiveness to the conventionally lauded "Best Stopper Calibers".

( for the sake of this argument we are talking .32" versus .45")

- How can this be? - My suggestion goes something like this ... If a destructive/explosive energetic device weighing e.g. 200 grams is inserted into a space and it completely & effectively destroys that spaces contents ... then you insert a twice as powerful (400 gram) device into a second similarly filled 'room' and activate it - are that second example room's contents still destroyed?

If the answer is Yes - then why waste that additional power and weight and surplus energy -when the lighter, more compact but equally effective device is more efficient and easier to deploy?

- Answers please - written on the back of a bottle of single Malt whiskey (Irish).

Marty K.