ATX762
Lil-Rokslider
Not trying to make any ground-breaking statements here, but something occurred to me when I was chrono-ing some loads yesterday, which is that my short-action shorter barreled 7mm-08's are generally pretty close, velocity- and energy- wise, to my long-action medium barreled 270's.
I've always had a soft spot for the 270, kills well and doesn't recoil much, but once I sort of looked the chronograph data I've collected on both the 270 and the 7mm-08 over the past few years, something became clear to me: the 7-08 basically equals the 270 in velocity and energy if you are using the typical 22" 270 factory barrel. And the 7-08 does this with a shorter barrel and in a shorter action.
Obviously nearly all factory ammo shoots slower than what is claimed on the box, because factory ammo is chronographed out of long test barrels, etc.
But of all the calibers I've owned, 270 to me has by far the biggest delta between factory-claimed and actual velocity. Guessing there are two reasons for this: A) it's a somewhat overbore cartridge but is not treated as such by rifle makers who are speccing the barrel length--they treat it like a 30-06 or 308, which lose less in a shorter barrel (esp the 308).
B) Being as conventional cup and core bullets don't always hold together all that well above 2900 fps, I have a suspicion that so manufacturers don't really like to load them much faster than that, regardless of pressure/velocity capabilities of the cartridge.
Some numbers:
My 20" 7-08 shoots most factory 120gr loads at about 2950 FPS. My 18.5" shoots them around 2900 fps.
Versus--
both the 22" barreled 270's I've owned shoot 130gr factory loads in the 2825-2850 range (Remington and Winchester). The Federal stuff (both the blue box and the premium stuff) runs noticeably faster, around 2925 fps.
Stepping up to 139 or 140grain factory loads: my 20 inch 7mm-08 shoots them around 2750-2800 fps while my 18.5 inch launches them around 2700-2725 fps. And I had a 16.5" 7-08 that launched them at around 2650-2675.
By comparison, my 22" 270's both launch 140 grain factory loads at around 2750. The same or less than my 20" 7-08 with the same weight bullet.
In short, if you're looking for 277 or 284 caliber rifle with a barrel in the 18-22" range, and you're shooting mostly factory ammo, you are better off with a 7mm-08. You are getting basically identical energy in a shorter action and a shorter barrel.
Obviously, in the end...it's all academic and both rounds both kill stuff real dead.
Also worth mentioning--the sole exception to the 270 factory ammo being way slower than what is claimed on the box is the Hornady Superperformance 270 130gr load which launches 130gr pills at a proper 3125-3140 fps out of both the 22" barreled 270's I've shot it out of.
Just thought I'd mention. Hope others find this useful, or, at least, not completely boring.
(NB--All the above data collected with an Ohler Model 35 chronograph.)
I've always had a soft spot for the 270, kills well and doesn't recoil much, but once I sort of looked the chronograph data I've collected on both the 270 and the 7mm-08 over the past few years, something became clear to me: the 7-08 basically equals the 270 in velocity and energy if you are using the typical 22" 270 factory barrel. And the 7-08 does this with a shorter barrel and in a shorter action.
Obviously nearly all factory ammo shoots slower than what is claimed on the box, because factory ammo is chronographed out of long test barrels, etc.
But of all the calibers I've owned, 270 to me has by far the biggest delta between factory-claimed and actual velocity. Guessing there are two reasons for this: A) it's a somewhat overbore cartridge but is not treated as such by rifle makers who are speccing the barrel length--they treat it like a 30-06 or 308, which lose less in a shorter barrel (esp the 308).
B) Being as conventional cup and core bullets don't always hold together all that well above 2900 fps, I have a suspicion that so manufacturers don't really like to load them much faster than that, regardless of pressure/velocity capabilities of the cartridge.
Some numbers:
My 20" 7-08 shoots most factory 120gr loads at about 2950 FPS. My 18.5" shoots them around 2900 fps.
Versus--
both the 22" barreled 270's I've owned shoot 130gr factory loads in the 2825-2850 range (Remington and Winchester). The Federal stuff (both the blue box and the premium stuff) runs noticeably faster, around 2925 fps.
Stepping up to 139 or 140grain factory loads: my 20 inch 7mm-08 shoots them around 2750-2800 fps while my 18.5 inch launches them around 2700-2725 fps. And I had a 16.5" 7-08 that launched them at around 2650-2675.
By comparison, my 22" 270's both launch 140 grain factory loads at around 2750. The same or less than my 20" 7-08 with the same weight bullet.
In short, if you're looking for 277 or 284 caliber rifle with a barrel in the 18-22" range, and you're shooting mostly factory ammo, you are better off with a 7mm-08. You are getting basically identical energy in a shorter action and a shorter barrel.
Obviously, in the end...it's all academic and both rounds both kill stuff real dead.
Also worth mentioning--the sole exception to the 270 factory ammo being way slower than what is claimed on the box is the Hornady Superperformance 270 130gr load which launches 130gr pills at a proper 3125-3140 fps out of both the 22" barreled 270's I've shot it out of.
Just thought I'd mention. Hope others find this useful, or, at least, not completely boring.
(NB--All the above data collected with an Ohler Model 35 chronograph.)
