Ballistic Charts for 7mm-08
I am trying to figure out listed ballistics on a 7mm-08. The problem is that most all of the guns chambered in 7mm-08 seem to have 22" barrels, yet all of the ballistic charts are based on a 24" barrel. This seems to make comparing ballistics, say between a 7mm-08 and a .270 Win, an apples/oranges situation since most .270s do come with 24" barrels. For comparison is it necessary to adjust the 7mm-08 and similar guns downward to get an accurate comparison? And if so, how do you do so (fps, trajectory, energy, etc.)?
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It is a bit unclear to me as to what you are attempting to accomplish, but in general, it seems that you are trying to compare the .270 Winchester with the 7mm-08.
First, I would say that at the best and maximum loads for each cartridge, and, I am not even going to look at the charts, that the .270 Winchester will have an edge, by about 100 or 150 fps, with comparable weight bullets. As you probably know, there is only .007 difference in caliber between these two, and the .270 case is somewhat larger. So, other things being equal, it will hold the edge with the best loads.0 -
The 7-08 is fairly good about not losing velocity with shorter barrels, going from 24 to 22 inches might cost you as much as 30fps on the velocity with the same barrel/chamber. Note that the difference between different barrels/chambers can be quite a bit higher than that.
IOW In the real world a sloppy chamber in the 270 vs a tight one in the 7-08 could well show that 7-08 to be better than the 270, while the oppsite would make the 7-08 look slow.
Personaly, I'd split the difference and run a 280 Rem (7mm-06, 7mm Rem Express, all-ee same-e)0 -
Actually Wolf , most .270 Win.s have 22" barrels . Most 25-06s have a 24" barrels . What I do with ballistic charts or reloading manuals is factor in barrel length . If you barrel is 2" longer than the one used in testing add 80FPS . If your barrel is 2" shorter subtract 80FPS . Might not be dead nuts but , in the ballpark . 0 -
famous wolf,
The reality of your situation is that you're trying to make two sets of data into absolutes and based on all of the variables in this process, you're not going to succeed. Besides, there is no hyper-critical reason to have the absolutes in the first place. The data available online and through the manufacturers of powder and ammunition is close enough to gain the information you need. Common sense should supply the rest.
As an example:
Remington's ballistic site lists the .270 Win. with a 140 gr. bullet at 2925 FPS.
Then they list the 7mm-08 with a 140 gr. bullet at 2860 FPS.
The larger capacity .270 Win. case should be capable of more velocity given an appropriate barrel length to burn the powder and create the gas that pushes the bullet. The smaller capacity case of the 7mm-08 will usually lag behind the larger .270 Win.
The exceptions to this could be the Light Magnum and similar manufacturer's loads which might get closer to the .270 Win. performance. However, these techniques and powders are not available to the general public so you are relegated to buying factory ammunition.
We could quibble about the effect of 2" of barrel length and quote all sorts of authorities regarding velocities and loss thereof but for the real world and the average citizen shooter, save yourself the aggravation and time by just using the data as an easy assessment.
Best.0 -
look at www.winchester.com and go to the ballistic calculator. It figures everything for you. 0 -
famous wolf,
As noted just use the ballistics given. There can be enough of a difference in the rifle you buy to make the minimal difference a non-factor. In fact, the difference in velocities IS a non factor pretty much unless you want to shoot long range. And to shoot long range successfully (consistent accuracy) you should probably be reloading.
If you are looking to buy a rifle and use it for long range I d suggest the 7mm-08 because there are high BC bullets for it. There isn't much of a selection of high BC bullets in .270 cal. Berger does have VLD hunting bullets that are good. but, not as good as the higher 7mm bullets.
Conversely, if you are looking to hunt, there is everything you need in .270. Plus it's one of those cartridges that you can go to any mom & pop store anywhere when you are out at the end of the line and find ammo for. It's just that popular. And for good reason. As noted it has better ballistics than the 7mm-08 for hunting ranges because of it's bigger case.
I always heard you could find 30-06 and .308, but most places ran out of those this past year. .270 could be found just about anywhere. 7mm-08 could only be found at the bigger "X"-mart type stores.
Anyhow, that's what I've found the past few years. And why I would choose either for it's intended use. Both will work good for either just each has it's better area to work from.
{edited for spelling}0
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