7mm Remington Magnum Journal

Article #4 December, 2003

Comparing the 7mm Rem. Mag with the Other 7mm Magnums - Which is the Best ????

Introduction

The 7mm Remington Magnum is not the new kid on the block.  It's not the latest fad, which these days includes Ultra Mags, Short Mags, Short Ultra Mags, Super Short Mags, and about any other combination of Super, Ultra, Mega, or any other extreme adjective.  Last year it turned 40 years old.  It would now be 41 years old, which according to my math is 12 years older than this author.  I could respectfully call it "Uncle 7". 

With all of these new, high-octane, super fancy cartridges straining to access our pocketbooks, I thought maybe we should do a bit of comparison and see how they stack up with the tried and true 7mm Remington Magnum.  We'll objectively compare velocities, energies, and trajectories, in addition to case capacities, ammunition costs, and whatever else we can find to compare.  After the comparisons, we'll discuss the results and figure out if maybe it's time to send the old "Uncle 7" out on the ice flow and replace it with something newer, younger, and potentially more powerful.

Factory Load Comparisons

Let's compare some factory loads of the various 7mm Magnums currently on the market.  We'll limit the discussion to commonly available ammunition from large producers.  The fastest factory produced load in each weight was selected for comparison.  These loads will be listed below.  All data comes from information supplied by the ammunition manufacturers, not from actually chronographed data.  Your velocities may vary substantially from that provided by manufacturers.  Most data is gathered from 24" barrels, while most of the larger 7mm Magnums are equipped with 26" barrels.

Factory Velocity and Energy Table

Cartridge   Muzzle Velocity       Muzzle Energy    
  140 gr. 150 gr. 160 gr. 175 gr. 140 gr. 150 gr. 160 gr. 175 gr.
7mm RM 3250 3110 2950 2860 3300 3220 3090 3180
7mm Weath. 3340 3300 3200 3070 3443 3627 3638 3662
7mm STW 3325 3250 3200 - 3436 3520 3640 -
7mm RUM 3425 - 3200 - 3646 - 3637 -
7mm WSM 3225 3200 2990 - 3223 3410 3176 -
7mm SAUM 3175 3110 2960 - 3133 3221 3112 -

 

Percentage advantage or disadvantage over 7mm Remington Magnum

Cartridge   Muzzle Velocity (FPS)     Muzzle Energy (Ft.-Lbs.)  
  140 gr. 150 gr. 160 gr. 175 gr. 140 gr. 150 gr. 160 gr. 175 gr.
7mm RM 0 0 0 0 0 0 0 0
7mm Weath. +2.7% +6.1% +8.5% +7.3% +4.3% +12.6% +17.7% +15.1%
7mm STW +2.3% +4.5% +8.5% - +4.1% +9.3% +17.7% -
7mm RUM +5.4% - +8.5% - +10.5% - +17.7% -
7mm WSM -0.8% +2.9% +1.4% - -2.3% +5.9% +2.8% -
7mm SAUM -2.4% 0 +0.3% - -5% 0 +0.7% -

 

Trajectory Comparison - Bullet drop at 400 yards.  All trajectories are based on a 200 yard Zero.

Cartridge   400yd. Drop (inches)       Compared to 7mm RM    
  140 gr. 150 gr. 160 gr. 175 gr. 140 gr. 150 gr. 160 gr. 175 gr.
7mm RM -16.6 -17.4 -19.4 -21.3 0 0 0 0
7mm Weath. -15.9 -15.1 -16.4 -18.2 +0.7 +2.3 +3.0 +3.1
7mm STW -16.1 -16.7 -15.7 - +0.5 +0.7 +3.7 -
7mm RUM -14.4 - -16.4 - +2.2 - +3.0 -
7mm WSM -16.4 -18.6 -20.8 - +0.2 -1.2 -1.4 -
7mm SAUM -17.7 -19.7 -19.6 - -1.1 -2.3 -0.2 -

In the comparison table,  "+" is used to indicate flatter trajectory, a"-" is used to indicate a more curved trajectory

 

Cost of a Typical Box of Premium Ammunition (from MidwayUSA website 11/20/2003)

Comparison is for a box of "premium" 160 gr. Ammunition (Nosler Partitions where available)

Cartridge

Cost per 20 rds. (US$)

% Difference from 7mm RM
7mm Rem Mag $32.53 0
7mm Weatherby $51.49 +58%
7mm STW $37.69 +16%
7mm RUM $34.99 +8%
7mm WSM $30.99 -5%
7mm SAUM $32.16 -1%

Comparison of Case Capacity

Cartridge

Case Capacity (gr. H20)

% Difference from 7mm RM
7mm Rem Mag 83.2 (W-W) 0
7mm Weatherby 87.5 (Wby.) +5.1%
7mm STW 98.3 (R-P) +18.1%
7mm RUM 111.7 (R-P) +34.3%
7mm WSM 83.0 (W-W) -0.3%
7mm SAUM 75.0 (R-P) -10%

Ammunition Used for Comparison

7mm Remington Magnum

7mm Weatherby Magnum

7mm STW

7mm Remington Ultra Mag

7mm WSM

7mm Remington SAUM

The Official Un-Scientific 7mm Magnum Comparison Index

To attempt to compare all of the common 7mm magnums, we came up with this completely unscientific formula.  This formula attempts to take velocity, efficiency, trajectory, and cost into comparison.  The formula is as follows:

Index = (Velocity/case capacity) + (Muzzle Velocity/100) - 400 yard trajectory - (10x $/rd)

This formula was derived to give equal weight to each factor.  Believe me, it's not based on any sound mathematical or scientific formula, but rather what I could come up with as I sit at my desk and watch some rugby on TV.

Cartridge Veloc./Case Capacity Velocity/100 400 Yard Trajectory 10x $/round Total Score
7mm Rem Mag 35.46 29.5 -19.4 16.2 29.36
7mm Weatherby 36.57 32.0 -16.4 25.7 26.47
7mm STW 32.55 32.0 -15.7 18.8 30.05
7mm RUM 28.65 32.0 -16.4 17.5 26.75
7mm WSM 36.02 29.9 -20.8 15.5 29.62
7mm SAUM 39.47 29.6 -19.6 16.1 33.37

Discussion and Analysis

We've compared velocities, energies, trajectories, cost, and efficiency.  I tried to factor in some of the other things you read about in the gun magazines.  Things like lower perceived recoil, newness and coolness, the Weatherby "Mystique", and a few other marketing mechanisms.  Unfortunately, I was unable to quantify these, so we had to stick with known values. 

The 7mm Remington SAUM seems to come out ahead, largely based on it's excellent efficiency.  The 7mm Remington Ultra Mag seems to be an underachiever based on it's low efficiency.  The 7mm Weatherby is the best performer until you factor in the high cost of Weatherby factory ammunition.  The trusty 7mm Remington Magnum finishes in the middle of the pack, nearly equal to the 7mm WSM. 

After analyzing the factory ammunition, the comparison among the same cartridges when reloaded begs to be performed.  The 7mm STW, 7mm Rem Mag, and 7mm RUM can certainly be improved by handloading, while the other cartridges are probably at the top of their game in factory form.  All cartridges will be cheaper to reload, and I have the feeling that the 7mm Weatherby may move up in the rankings.  Additionally, we can compare all of them with the same projectile to add a little more consistency to the comparison. 

I still believe that if a hunter is going to travel to remote locations, a standardized cartridge is a wise choice.  A rifle that you are unable to get ammunition for isn't worth much.  The chances of this happening are slim, but sometimes Mr. Murphy appears when least expected.

What do the added (or lost) velocities gain you?  On paper, perhaps a bit more delivered energy on those long shots, and a bit flatter trajectory.  In the real world, all would be very effective on game.  For long distance shooting of heavy game, such as elk, moose, eland, kudu, or wildebeest, there may be some advantages, however the key aspect in any long-range shooting is marksmanship. 

Pros of the Faster Magnums

Cons of the Faster Magnums

Next time, we'll compare these same things, using reloaded data to see how these cartridges stack up.  To be honest, I'm not sure that there is a bad choice among them. 

I'll stick with my trusty "Uncle 7", but I don't think you can go wrong with any of them.  Until next time, keep shooting and stay safe.

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