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  #1  
Old 10/19/08, 10:26 PM
 
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.308 vs 7mm-08

So I was talking deer rifles with the BIL and his buddy got a 7mm-08 and was talking about how flat it shot - flatter than his old .308. Now, I don't have the ballistics charts memorized, but I seem to remember that the 7mm-08 dropped an extra inch or two at 300 meters compared to a .308 with similar grains moving downrange. Am I right or am I missing something?

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  #2  
Old 10/20/08, 02:13 AM
 
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In reality the ballistics are pretty much the same with similar bullet weights. Comparing the 139/140 grain bullet of the 7mm-08 and the 150 grain bullet of the .308, there's less than 2 inches difference in trajectory out to 400 yards. Assuming 200 yard zeros in both rifles, the 7mm-08 is 7.4 inches low at 300 yards and 21.5 inches low at 400. The .308 is 7.9 inches low at 300 and 23.1 inches low at 400. Past 400 yards, the .308 drops off quicker, mostly due to the greater ballistic coefficient of the longer 7mm bullet. I got these numbers from the Hornady web site.

If your BIL's buddy really is getting much flatter trajectory from the 7mm-08, my guess is that he was using the much heavier 180 grain bullets in his .308. That's the only thing I can think of to explain a large difference. The only ballistic reason anyway.

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  #3  
Old 10/20/08, 07:22 AM
 
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I thought the .308 was flatter if you fired 150 grain out of each - like 7 inch drop for .308 and 9 inch drop for 7mm-08 at 300 meters.

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  #4  
Old 10/20/08, 07:38 AM
 
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You're right Tom, the 150 grain bullet does drop less in .308 than 7mm-08. I compared the 139gr. 7mm-08 vs. the 150 gr. .308 because the two web sites I checked (Hornady and Remington) didn't offer 150 grain factory loaded ammo for the 7mm-08. I just checked the Federal web site and their stats show the 150 gr. 7mm-08 9.2 inches low at 300 yards and 26.5 inches low at 400. Again using a 200 yard zero.

It's still not much of a difference though. Less than 3.5 inches at 400 yards.

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  #5  
Old 10/20/08, 07:58 AM
 
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Yeah, I guess I just really have a sentimental attachment to the .308 and get a little defensive when someone tries to poke at it. The only thing in the "family" that I have fired and been convinced really is flatter is the 7mm mag. But for hunting, you can throw away meat using a 7mm mag so...

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Old 10/20/08, 08:02 AM
 
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Oops ... wrong place.

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  #7  
Old 10/20/08, 08:16 AM
 
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Yeah, the .308's always been a favorite of mine. The 7mm-08 is a very good round but unless I could afford enough rifles that I just wanted something different, I'd pick the .308 over it every time.

Any of the 7mm magnums will shoot flatter than the .308 (or my all time favorite .30-06) but I consider them more specialized tools than the .308 or 7mm-08. In general you need a longer, heavier rifle (except for the short magnums) plus, the ammo costs a lot more. Neither of those are generally good things in my opinion.

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  #8  
Old 10/20/08, 09:15 AM
 
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Yeah, when you are going to put a 22" barreled bolt-action rifle on your shoulder with a good scope to be "ready for anything" - hunting deer, killing a bear, etc. - then I think the .308 is just the best all around rifle. Yes, I got very friendly with it in the military so its always been the standard with which I judge all others, but nothing has replaced it yet. Of course, the "yet" proves I am just one rifle away...

I am hopefully going to get to fire the .416 Barrett early next year. I don't think that will replace the .308 as my "go to" round, but it might just become my new favorite.

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  #9  
Old 10/20/08, 12:30 PM
 
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Quote:
Originally Posted by Tom Bombadil View Post

then I think the .308 is just the best all around rifle.

The .308 is fine for the folks that can't handle a 30.06 which will give another 200 yrds of use for the same bullet weight


Now seriously - the 7.62 NATO has a lower working chamber pressure than the .308 Win and the .308 Win has tighter throat tolerances than the 7.62 NATO, so while they are visually identical, it's not a good idea to be swapping ammo between them, especial when you have older firearms that have been converted to take the more powerful 7.62 NATO - their receivers may not have enough margen of safety to handle .308 Win.
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Old 10/20/08, 01:30 PM
 
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Originally Posted by Greg H. View Post
The .308 is fine for the folks that can't handle a 30.06 which will give another 200 yrds of use for the same bullet weight


Now seriously - the 7.62 NATO has a lower working chamber pressure than the .308 Win and the .308 Win has tighter throat tolerances than the 7.62 NATO, so while they are visually identical, it's not a good idea to be swapping ammo between them, especial when you have older firearms that have been converted to take the more powerful 7.62 NATO - their receivers may not have enough margen of safety to handle .308 Win.
30-06 is my very close number 2. My SIL just got a deer rifle in 30-06 and it is awesome.
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  #11  
Old 10/20/08, 01:38 PM
 
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Originally Posted by Greg H. View Post
The .308 is fine for the folks that can't handle a 30.06 which will give another 200 yrds of use for the same bullet weight
Actually with factory ammo the 06 and the .308 are pretty compareable. This is due to the SAAMI specs for the two cartridges, the .308 being "younger" it's loaded to slightly higher pressure.

The 30-06 is just about 200 FPS faster than a .308 with the same bullets in both the 150 and 180 grain loadings. The muzzle energies are also similar, within 200 FTLBs and with the same bullets the trajectories are only about 2 inches of each other out to 500 yards with a 180 grain bullet. If you use the Maximum Point Blank Range method of sighting in, the 30-06 will give you about a 30-50 yard advantage on a 6" kill zone, meaning that it will stay within 3 inches below line of sight for a little longer distance:

http://www.remington.com/products/ammun ... WA*PG308W3

No animal on this planet will appreciate the difference based on the ballistics out to normal hunting distances.

Now if you handload in a modern rifle, there's "no replacement for displacement" and you can eek out more velocity out of an 06. But, when compared with the .308s advantages in being able to be chambered in a short stiff action allowing for a lighter rifle, combined with the .308s slightly better accuracy, it really isn't that big a plus.

Chuck
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  #12  
Old 10/20/08, 01:56 PM
 
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Originally Posted by Tom Bombadil View Post
30-06 is my very close number 2. My SIL just got a deer rifle in 30-06 and it is awesome.

My Springfield 1903A3 always goes to the range with me - it doesn't matter what other firearm goes or doesn't go, the 03A3 is always there.
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  #13  
Old 10/20/08, 02:43 PM
 
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Originally Posted by Chuck R. View Post
Actually with factory ammo the 06 and the .308 are pretty compareable. This is due to the SAAMI specs for the two cartridges, the .308 being "younger" it's loaded to slightly higher pressure.


The 30-06 is just about 200 FPS faster than a .308 with the same bullets in both the 150 and 180 grain loadings.
You have hit the nail on the head.

The only reasion that the .308 comes that close to the 30.06 is because of the increased pressure - Personaly I have never been convinced that increased pressure is nessasarly a good thing - may not be a bad thing either, but not nessesarly a good thing.

Take a look at the 7.62 NATO, which is loaded to the same pressure as the 30.06, and they have to reduce bullet weight in order to get the same velocity 152 grns for the 30.06 and 147 for the 7.62 NATO and the velocities still don't equal, and you start loosing effective range.

Quote:
Originally Posted by Chuck R. View Post
The muzzle energies are also similar, within 200 FTLBs and with the same bullets the trajectories are only about 2 inches of each other out to 500 yards with a 180 grain bullet. If you use the Maximum Point Blank Range method of sighting in, the 30-06 will give you about a 30-50 yard advantage on a 6" kill zone, meaning that it will stay within 3 inches below line of sight for a little longer distance:

http://www.remington.com/products/ammun ... WA*PG308W3

No animal on this planet will appreciate the difference based on the ballistics out to normal hunting distances.

Now if you handload in a modern rifle, there's "no replacement for displacement" and you can eek out more velocity out of an 06. But, when compared with the .308s advantages in being able to be chambered in a short stiff action allowing for a lighter rifle, combined with the .308s slightly better accuracy, it really isn't that big a plus.

Chuck
There is an advantage to a short stiff action?
What is it?

The only advantage the .308 has in accuracy is with light weight bullets due to the usualy faster twist, when it comes to 150 grns it's about the break even point, with anything higher, the 30.06 ( at least wise with older .06's )has the advantage in accuracy.

Most older 30.06's used to run to 1-12 but as the .308 and lighter bullets became popular, the newer rifles used the same 1-10 twist for the .06 as they were for the .308 barrels - but we are talking about a function of barrel twist, and bullet weight.

I have been getting some nice surplus Greek ammo for my .06 and it's 155 grs at 2975 fps, which stiff even compared to .308 Win commerical loadings.
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  #14  
Old 10/25/08, 01:56 AM
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Within sane, ethical hunting ranges there is very little difference between the 7mm-08 Remington, .308 Winchester, and .30-06 Springfield save for felt recoil out to 200 yards. All three will take down deer within that range.

If you are shooting beyond 300 yards as a matter of course then you would need to be an expert shot at that range because wind and drop become all the more important factors in hitting where you aim.

Ninety percent of deer are taken at 100 yards or less and 95 percent are taken at 200 yards or less.

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  #15  
Old 10/25/08, 09:26 AM
 
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Quote:
Originally Posted by Greg H. View Post

There is an advantage to a short stiff action?
What is it?

The only advantage the .308 has in accuracy is with light weight bullets due to the usualy faster twist, when it comes to 150 grns it's about the break even point, with anything higher, the 30.06 ( at least wise with older .06's )has the advantage in accuracy.

Most older 30.06's used to run to 1-12 but as the .308 and lighter bullets became popular, the newer rifles used the same 1-10 twist for the .06 as they were for the .308 barrels - but we are talking about a function of barrel twist, and bullet weight.
The shorter stiffer action aids with the overall "harmonics"
of the barrel/action.

The .308 does have an accuracy advantage even with the same twist barrels and the same bullets. It’s got to do with the expansion ratio: bore to chamber size. The longer powder column is more difficult to get an even consistent ignition and burn. When chronographed it's easier to get good stats IE standard deviation and extreme spread from a cartridge with a good expansion ratio. At the longer distances the inconsistencies translate into vertical stringing.

Here’s a pretty good article on it:

http://www.snipercountry.com/Articles/AccuracyFacts.asp

The bottom line is the .308 eclipsed the 30-06 as a target cartridge for a reason.


Chuck
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  #16  
Old 10/25/08, 11:08 AM
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Originally Posted by Tom Bombadil View Post
Yeah, I guess I just really have a sentimental attachment to the .308 and get a little defensive when someone tries to poke at it. The only thing in the "family" that I have fired and been convinced really is flatter is the 7mm mag. But for hunting, you can throw away meat using a 7mm mag so...
I have not found this to be true:[/QUOTE] 7mm mag. But for hunting, you can throw away meat using a 7mm mag so......[/QUOTE]

I have killed many white tails, mules, elk and never have destroyed any meat, unless you talking heart/lungs.
Factory Rem. 150 gr cor-loc's.
Ranges have varied from 300 yds to 6 ft.
I suspect shot placement has a lot to do with this.

[QUOTE]Yeah, I guess I just really have a sentimental attachment to the .308 and get a little defensive when someone tries to poke at it. [QUOTE]

I would agree that the .308 is a good all-round, round, as is the 30-06, but for me the Rem 7mm mag is "my" favorite.
Working with a .300 wsm now, so we'll see if my affection changes.

Most people "go with what they know" and shoot best when they feel confident/comfortable with a particular round/rifle.

Most game animals don't really care if the bullet is moving a couple of hundred ft per second faster or slower.
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Old 10/25/08, 03:04 PM
 
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Back to the question from the OP...All elements being equal including bullet weight and shape, The 7mm/08 will shoot flatter (drop less) and the advantage will increase with the range. Simple ballistics...Glen

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  #18  
Old 10/25/08, 06:05 PM
 
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Originally Posted by hunter63 View Post
I would agree that the .308 is a good all-round, round, as is the 30-06, but for me the Rem 7mm mag is "my" favorite.
Working with a .300 wsm now, so we'll see if my affection changes.

Most people "go with what they know" and shoot best when they feel confident/comfortable with a particular round/rifle.

Most game animals don't really care if the bullet is moving a couple of hundred ft per second faster or slower.
One of the hunting crew at work basically blew the leg off a doe with a 7mm mag at less than 50 yards. Yes, he blew the shot and it was his poor aim that was ultimately to blame, but I have never seen that happen with a .308.
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Old 10/25/08, 06:33 PM
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Originally Posted by Tom Bombadil View Post
One of the hunting crew at work basically blew the leg off a doe with a 7mm mag at less than 50 yards. Yes, he blew the shot and it was his poor aim that was ultimately to blame, but I have never seen that happen with a .308.
This was the reason for saying that 7 mag ruins meat?
I would guess this would happen with most any high powered load.

I've only seen this once, on a small spike buck that I killed, someone (don't know what it was shot with), had shot off a foot.

Each to his own, but I still disagree with you, based on my experience, not "I heard about............from a guy......... etc".
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Old 10/26/08, 02:38 AM
 
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Originally Posted by quietstar View Post
Back to the question from the OP...All elements being equal including bullet weight and shape, The 7mm/08 will shoot flatter (drop less) and the advantage will increase with the range. Simple ballistics...Glen

Simple ballistics yes...but in favor of the .308 not the 7mm-08. Using the same bullet weight (150 grains for numbers quoted) and same barrel length, the .308 drops about 3.5 inches less at 400 yards than the 7mm-08. I used the 150 grain bullet because it is the only weight I could find in both calibers in factory ammo.
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