Trajectory, Meat Damage and Knock-Down

Trajectory, Meat Damage, and Knock-Down

The Practical Realities of Effective, Long Range Hunting Cartridges.

by Eben Brown
There are two areas of modern rifle opinion that I think are not correct:
1. That extra high velocity rifle cartridges are necessarily so much flatter shooting than medium velocity cartridges... the Myth of the so-called "500 Yard Cartridge" and,
2. That high velocity and energy are necessarily desirable at knocking down game... They aren't.
What follows is an argument in favor of using medium velocities and heavy bullets for hunting...
We're going to look at the realities of bullet trajectory relative to velocity; Meat damage in relation to excessive energy; And Sectional Density as it relates to the Killing Power of a cartridge on big game.

Practical, Useable Trajectory - Prior to the distance at which your scope is zeroed, the trajectory has to be flat enough so that you don't have to concern yourself with it and can aim right on at deer sized game. This means that... The trajectory should rise and fall no more than about 3" prior to sight zero.
After sight zero, bullet drop accelerates. It's only predictable to the point where you can still estimate distance and a reasonable hold over to hit reliably... This is fundamentally true for all hunting cartridges.
So... The trajectory should drop no more than about 12" at the furthest hunting shot after sight zero.

Energies that Cause Excessive Meat Damage -- In several successful years hunting with the medium velocity 6.5X55 Swedish Mauser and the 6.5mm BRM, I never saw an animal shot where it ran away... and yet damage to the meat was small. Medium velocity kills without ruining your meat.
In contrast, I have observed that nearly every animal shot with a 30-06 exhibited excessive meat damage. Here's how we'll put a value on it: On two different occasions, deer shot at about 150 yards had their shoulders completely ruined where the bullet exited. The energy of a 30-06 bullet at 150 yards is 2561 ft/lbs. So... Bullet energies of more than 2500 ft/lbs. can produce excessive meat damage.
Sectional Densities and Velocities that Put Game Down -- The 6.5X55 Swedish Mauser is famous for being an extremely reliable game stopper. I believe the reason it works so well is a combination of two factors: High Sectional Density Bullets and Impact at Medium Range Velocites.
Here's a simple illustration of how it works:n of how it works: If you shoot an aluminum pop can with a high velocity (800fps) air rifle, the soft lead pellet zips right through the can without disturbing it. Now, if you shoot that same can with a low velocity (non-expanding) BB gun at only 300-400 fps, it will make a dent, rip a hole through, and knock the can over. Medium velocity actually puts more whack into the target!
BRM Cartridges: The original Swedish Mauser 140 grain bullet has Sectional Density between .270 and .290 and Velocity UNDER 2,500 fps. These are the same characteristics of our BRM cartridges but, they're incorporated into a more efficient, modern cartridge design that's suited to modern powders and bullets.
Conclusions: Except for extreme situations, almost nobody needs a large magnum cartridge for big game hunting. Look at the green areas of the chart above to see the narrow range of suitability for the big magnums. Traditional cartridges like .308 Win and 30-06 are certainly more practical than magnums, but look at the green sections above... Even those cartridges aren't optimum for all hunting situations. On the other hand: Our BRM Cartridges Shine Under the Most Popular, Practical Hunting Situations!
Mar 30th 2023 EB

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