JagMagMan

In another thread the issue of the 30-06 vs. the .308 was raised.
I am partial to the .308, but understand, that is just my personal preference!
I do have some experience with the 7MM-08, and I've seen large deer KO'ed with the 7MM-08 at well over 300 yards, and in most ballistic charts, I've noticed the 7MM-08 seems to have more "retained energy" when the .308 starts slowing down.
That is where this thread goes...
Does anyone have any "real world " experience that this statement is true?
If so, the 7MM-08 is just about the "perfect"cartridge for game through Mule Deer size.

James B

To start with, the 7MM-08 would be a near perfect deer cartridge and is. I knew the two would be close so I got out my chronograph book and did some calculating. To began you need to start with bullets of equal SD to compare. In this case, its easy. The 140 grain 7MM bullet and the 165 grain 30 cal bullet have equal SD. Starting both at 2900 fps which is the highest readings I have ever obtained, they come out very close. When Zeroed at 200 yards the drop at 300 is 7.7 inches for both. At 400 the 7MM bulet dropd one tenth of an inch more that the 30 cal. bullet. The 308 bullet however retains almost 200 LB more energy at 400 yards. For all practical purposes the are ballistic twins when using equal SD bullets.

These things can very with barrel length and such but keeping things as equal as possible they are two peas in a pod. Both are great cartridges and very efficient for output vs input. Lots of bang for the buck so to speak. When all things are considered including the extra drag and friction of the extra velocity, which the manuals don't show, the 308 Win. does not give up much to even the 300 WSM. In the field at 500 yards and beyond, people would be shockedat how little difference there really is. The extra velocity of the magnums creates more friction and drag on the bullet. I saw it all worked out on computers at a seminar given by Rick Jamison. He is one of the top ballistics men alive. IMO

JagMagMan

Thanks! Good info James, I have not compared them with bullets of equal SD.

USMC PMI

Excellent post James!!!

James B

Thanks Gentlemen.

ipscshooter

I was reviewing the Winchester ballistics tables for the .308, .30-06 and 300 WSM and then came back and found this. You're right, the .308 does start to gain a little ground at 500 yards, although, the gains aren't really very big.

At the muzzle, the .308 is 100 fps slower than the 06, and 475 fps slower than the WSM. At 500 yards, the .308 is only 7p fps slower than the 06 and 375 fps slower than the WSM. In energy, this translates to 191 ft lbs less than the 06 at the muzzle and 968 ft lbs less than the WSM at the muzzle. At 500 yards, the .308 has 100 ft lbs less than the 06 and 513 less than the WSM.

These comparisons were all with the 150 grain XP3 premium ammo.

Comparing the .308 to the 7mm-08 (using a 140 grain ballistic silvertip), the 7mm is 55 fps slower at the muzzle and 11 fps slower at 500 yards. The 7mm has 272 ft lbs less energy at the muzzle and 90 ft lbs less energy at 500 yards.

Sighted for a 200 yard zero, the WSM drops 32 inches at 500, the 06 drops 42.2 inches, the .308 drops 45.7 inches, and the 7mm-08 drops 46.9 inches.

statjunk

The drop was the deciding factor in upgrading to a 300WM from .308. I still use both though.

Tom

spuddog

Guys, Thanks for asking this question and for the responses. These answers have been much more practical and to the point than the typical "X vs Y" or "What caliber?" threads. I've been mashing this stuff around in my head as well and couldn't seem to get down to brass tacks on it.

Thanks again.

DANTHEHUNTER

James B excellent post (once agin) that has been my saying all along most focus on the big bang instead of the output.I have a .300 win mag and I cant see that my deer with it are any deader (is that a word) then with my .270,.243,45/70,6.5x.284,or my .338 win mag.Lets focus on shooting skills more and not the calibur!!! Any rifle IMO above a .243 in the hands of a good shooter will take his game efficient and humane.

Doe Dumper

Dan thats what people tend to forget.....they get so caught up in caliber they forget about the most important thing of all..shot placement. If you cant put it where it needs to be..nothing short of a grenade launcher is gonna help.