I love the treads regarding calibers/cartridges for Africa...and elsewhere. I've read the other Title in this Forum (
First Safari - I’ll hunt plains game - What caliber?) extensively and there is a great deal of good information.
I reload a great deal and like to shoot a lot. I have my pet go-to loads but I'm always testing new recipes; I use my chrony extensively.
Here is my take and I'd like to hear the group's thoughts and data, especially when it comes to actual projectile velocities. In my mind, when it comes to terminal performance, it all comes down to the projectile connecting with the animal - payload on target - if you will. I'm not saying anything in this post that folks aren't already very familiar with, but I'm going into a bit of detail IOT ask some final questions.
Interestingly, when it comes to the .308 bullet, the 308 Win and 30-06 Sprg are nothing more than different launching platforms for the same bullets; of course the 30-06 can launch all weights at a higher velocity and this becomes of greater significance as the weights increase up to, and above, 165gr.
The 7x57, a rifle cartridge I have never owned or re-loaded for, is launching a different projectile, but of similar weights up to the 180gr area. Naturally, factory ammunition is anemic compared to what re-loaders can accomplish for modern rifles. But since I don't reload for this cartridge and thus have not tested where I can go, I can only guess the velocities I could get. (I do have a nice Rem 700 CDL LA that I've seriously considered re-chambering to 7x57 Mauser.)
When looking at velocity, one has to consider barrel length. Most reloading manuals (and factory ammo box data) use 24" barrels for testing and many hunting rifles for 30-06 are actually 22" with some even 20", while 308s are often from 22" all the way down to 18.5". I have several 308s and with varying lengths and there is a noted difference in
most cases. Hence, I can shoot 165gr bullet from a 20" barreled 30-06 and the same from a 24" barreled 308win and essentially negate any advantage the '06 had. Additionally, many rifle's "sweet spot" is not at max velocity to begin with...
Then we can look at what is the actual energy and penetration needed for a good, ethical kill on say, a Wildebeest or Kudu or Zebra, when shot in the vitals. It seems that most folks are shooting 300yds or less, with some exceptions being longer shots.
I know my ballistics for my favorite 308 and '06. For example, my 308 (20" barrel) launches a 165gr Swift Scirocco II at an avg 2695 fps as it's "sweet spot" and this is also about its MAX. My '06 (22" barrel) launches the same projectile at an avg velocity of 2815 fps in it's "sweet spot". This velocity difference is not insignificant at 300 yds, but when looking at terminal performance, does it make a truly significant difference? There is about 140 fp of energy difference (1703 vs 1845) and about an inch difference in drop/drift; shooting off sticks, I guarantee the inch difference means nothing to me...
***If you don't mind, and have your ballistic data, I'm curious what the "actual" velocities you are getting from your 308s, '06s, and 7x57s for your hunting projectiles. With this, one can easily calculate energy/drop/drift at given distances. This would go a long way in sussing out the terminal performance on game most are getting from their favorite and/or recommended cartridges/calibers.***
Here are my favorite platforms: All Ruger Hawkeye Hunters. (L-R) '06, 308 (my fav), and 6.5CM. I run an ultralight suppressor on them, which is currently sitting on the 308.
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