Home Forums Hunting & Shooting Ask The Gunwriters 7x57 vs 280

Another 10K of psi and you should get be able to get 2,850.

What are you 7x57 owners using for actions? Long or short? If not short then I don't see the need.

I've loaded for both and have owned several 280's, 3-4 7x57, but have only worked with 140's in each because there was no requirement for a 160 for my hunting.All these rifles had 22" barrels and ran the gamut from Remington Mountain rifles to full blown customs.

Bottom line was 2800-2850 from the 7x57;3000-3100 with 140's from the 280 Rem.Back then,only RL22 gave the velocities I liked with great accuracy from the 280.I have not messed with either cartridge in over a decade because they do nothing that can't be done with a 270.

Back in the 80's there were a few gungacks running around getting over 3000 from 140's in the 7x57 using Norma 205. I would not want a steady diet of those loads, even today.This is the same old story of the smaller case coming close to the larger case with light bullets, but the spread increases when bullet weight goes up.

I would say the chances of safely hitting 2900 with a 160 in the 7x57 are grim from sporter barrels.Only one load in the new Nosler manual hits that from the 280 Rem.

Much as I admire it,and setting "cool" factor aside,the 7x57 cannot deliver the velocities of a 280 because it holds less powder.If you desire 2900 from a 160 gr bullet, get the 280; even then, you'll be lucky to get it from 22" barrels at safe pressures IMO.

The 7x57 is what it is. A step above a 7/08 and step below a .280 which is a step below a 7RM. Nothing wrong with that. Each one is a great round. All depends on what you are using it for and how much recoil/noise you want to deal with.

so I'll stay with the 7x57, which incidentally, is a better chambering than the 7-08.

Don

I was the person who crunched the numbers and came up with the formula (approximate) that any increase or decrease in powder capacity results in 1/4 that increase in potential muzzle velocity, at the same pressure in the same bore size.

It is gratifying to see it quoted so much. Once I even saw it quoted as "the old 1/4 rule." I first published it in RIFLE or HANDLOADER (can't remember which) at most 10 years ago, which I guess qualifies as "old" in this era of the Internet.

I worked out the formula partly because of discussions like this. I had also grown weary of gun writers guessing how much "Ackley Improving" a round would increase the velocity.

The formula was developed by crunching the numbers from a bunch of handloading manuals. If you want to argue about it, feel free. But first spend a few days crunching numbers so we have something realistic to argue about.

The .280 has about 20% more powder capacity than the 7x57, with the same bullet seated to factory overall length (about 3.1" in the 7x57 and 3.35" in the .280). Exactly how much depends on
brass weight, but 20% is pretty close.

Thus the .280 can drive bullets about 5% faster when loaded to the same pressure, in the same barrel length. If the 7x57 is capable of 2700 fps with a 160-grain bullet, then the .280 will drive the same 160 to 2835. If the 7x57 is capable of 2900 with a 140, then the .280 can drive the same bullet to 3045, again everything else being equal.

I see that somebody has brought up the old myth about needing a longer barrel in the .280, to burn up all that slow powder. This is indeed an old one, but the truth is that just about all the smokeless powder that's going to burn in a rifle round (99%+) burns by the time the bullet has traveled maybe 2 inches in front of the chamber, exactly how far depending on various factors. The bullet continues to accelerate because the gas produced by the powder continues to expand, not because the powder is still burning.

In reality, the powder that produces the most velocity in a 26" barrel also produces the highest velocity in an 18" barrel.
This has been proven over and over again. In fact, the LEAST loss of any load's velocity in shorter barrels generally comes from a combination of slow-burning powder and heavy bullets.

That is a classic example of the oxymoron "false logic."

Hornady Light Magnums (and any other U.S. commercial ammo made by a member of SAAMI) still has to conform to SAAMI maximum pressures. SAAMI maximum pressures for the 7x57 are lower than for the .280, even in "Light Magnum" ammo. I don't have the numbers at hand, but believe the 7x57 maximum is around 50,000 psi, and the .280 maximum 60,000.

In fact, handloaders can safely exceed the muzzle velocity of Hornady Light Magnum 7x57 ammo with "modern" pressures of 60,000 psi or so, even in a 22" barrel. Look it up in Nosler's manual. The top muzzle velocity listed for 140-grain bullets in the 7x57 is 2892 fps. With the 139 Hornady (which has a shorter bearing surface than any 140-grain Nosler 7mm bullet) you can safely go up to 2950 or so.

I have owned a pile of 7x57's and .280's, and tested them in pressure lads. The difference is about what's indicated with the 1/4 formula, 5%. This is admittedly hard to pin down from most manual and factory data, because of the pressure differences between the rounds. Or even barrel length differences. Nosler's manual would be much more useful in this comparison (since they load both rounds to about the same pressure) except for the fact that they tested the 7x57 in a 22" barrel and the .280 in a 26" barrel.

The 5% difference does come out to around 150 fps for most bullet weights. This amounts to about what bullets from the .280 lose 50 yards from the muzzle. So in theory the .280 has about a 50-yard advantage over the 7x57.

In something like a quarter of a century of handloading and hunting with both rounds, however, I can generally say that the 7x57's bullets will get to whatever animal is being aimed at, and kill. As will the .280's.

Naturally, this is only if the hunter in question is familiar with the rifle in hand, an ideal I know we all strive for.