.280 Ackley Improved

.280 Remington
280 Remington.JPG
TypeRifle
Place of originUSA
Production history
DesignerRemington
Designed1957
ManufacturerRemington
Produced1957-Present
Variants.280 Ackley Improved
Specifications
Parent case.30-06
Bullet diameter.284 in (7.2 mm)
Neck diameter.315 in (8.0 mm)
Shoulder diameter.441 in (11.2 mm)
Base diameter.470 in (11.9 mm)
Rim diameter.473 in (12.0 mm)
Case length2.540 in (64.5 mm)
Overall length3.330 in (84.6 mm)
Case capacity67.9 gr H2O (4.40 cm3)
Rifling twist1 in 10 in (250 mm)
Primer typeLarge rifle
Maximum pressure (C.I.P.)58,740 psi (405.0 MPa)
Maximum pressure (SAAMI)60,000 psi (410 MPa)
Maximum CUP50,000 CUP
Ballistic performance
Bullet mass/type Velocity Energy
120 gr (8 g) SP 3,112 ft/s (949 m/s) 2,581 ft⋅lbf (3,499 J)
140 gr (9 g) HP 2,839 ft/s (865 m/s) 2,506 ft⋅lbf (3,398 J)
154 gr (10 g) SP 2,825 ft/s (861 m/s) 2,730 ft⋅lbf (3,700 J)
168 gr (11 g) HPBT 2,723 ft/s (830 m/s) 2,767 ft⋅lbf (3,752 J)
175 gr (11 g) SP 2,681 ft/s (817 m/s) 2,794 ft⋅lbf (3,788 J)
Test barrel length: 24"
Source(s): Accurate Powder

The .280 Remington, also known as the 7mm-06 Remington and 7mm Express Remington, was introduced in 1957 for the Remington model 740, 760, 721, and 725 rifles.

History[]

Having been released 32 years after the .270 Winchester, it had somewhat unspectacular sales. Remington renamed the cartridge in late 1978 to 7mm-06 Remington but just before the end of the year they renamed it again calling it the 7 mm Express in an attempt to increase sales. This resulted in people confusing it with the 7 mm Remington Magnum, and Remington changed the name back to .280 in 1981.[1]

Specifications[]

The .280 is based on the .30-06 necked down to accept 7 mm (.284 in) bullets, with the neck moved forward .050 in (1.27mm). The neck was deliberately moved forward to prevent chambering in a .270 Winchester rifle, as firing a .280 round in a .270 rifle could cause the projectile to get stuck in the barrel or rupture the barrel due to excessive pressure.[2]

.280 Remington vs .270 Winchester[]

The .280 Remington is capable of generating slightly higher velocities in heavier bullet weights (150 grains and above) than the .270 Winchester due to a marginally greater case capacity. However the ballistic coefficient of equal weight bullets favors .270 caliber bullets over 7mm (.284) bullets of similar design (in 2021 this is not the case - all 7mm bullets have better BCs than their .277 matches). In the heavier bullets (150 grains and above) of similar design the .280 Remington has a slight edge in muzzle energy.[2]

With equal weight bullets of similar design the .270 Winchester surpasses the .280 Remington's long range velocity and energy due to the 270's higher ballistic coefficient according to Federal's ammunition catalog. There are also many more factory loads available for the .270 Winchester over the .280 Remington at a lower price point due to the .270's much greater popularity.[2]

.280 vs .30-06[]

The .280 Remington is capable of developing energy nearly equal to the .30-06 Springfield, but with lighter bullets having a better ballistic coefficient. The .30-06 produces more energy than the .280 with bullets heavier than 180 grains, though .284" 175 grain bullets have a high sectional density of .310, compared to the 30-06 180 grain bullet with a moderate sectional density of .271. The .280 is suitable for hunting any game in North America with good shot placement.

SAAMI pressure limit for the .280 Remington is set at 60,000 PSI, 50,000 CUP.

Most American rifle and ammunition manufacturers catalogue the .280 Remington.[2]

In Europe the .280 Remington is not popular in bolt action rifles since it competes directly with the 7×64mm, which is of the almost exact same size as the .280 Remington but has slightly more power, because of having a slightly higher maximum allowed chamber pressure. The .280 Remington does, however, have a larger than expected number of European users in imported self-loading rifles such as those by Remington.

The .30-06 is substantially more popular and manufacturers thus offer a much greater selection of loads at a substantially lower price point.

While it is true that a .280 Remington case can be formed from a .30-06 Springfield case, the case length of a .30-06 is 63.3 millimetres (2.494 in) while the case length of a .280 is 64.5 millimetres (2.540 in), the same as a .30-03 Springfield. However, "The slight difference in length of reformed cases doesn't make any practical difference." [3]

.280 Ackley Improved[]

.280 Ackley Improved on the right

One of P.O. Ackley's earliest wildcats was the 7mm-06 Improved, which was made by necking down the .30-06 Springfield case and fire-forming it to have less body taper and a 40-degree shoulder angle. Soon after the .280 Remington came out, Fred Huntington reformed its case to an improved configuration with minimum body taper, a 35-degree shoulder angle, and called it the .280 RCBS. Since cases for the .280 RCBS could be formed by firing .280 Remington ammo in a rifle chambered for the former, Ackley abandoned the 7mm-06 Improved and started chambering rifles for the .280 RCBS. He then changed the 35-degree shoulder to 40-degrees and the .280 Ackley Improved was born. If barrel length and chamber pressure are equal, the .280 Ackley Improved is about 100 fps faster with all bullet weights than the standard .280 Remington. In 2007, ammunition manufacturer Nosler registered the .280 Ackley Improved with SAAMI and began providing factory loaded ammunition and rifles for it.

See also[]

References[]

  1. ^ The Versatile 280 at Outdoor Life By Jim Carmichel, September 18, 2007
  2. ^ a b c d Wu, Vivien (16 May 2015). ".280 Remington". Sporting Rifle. Retrieved 23 September 2021.
  3. ^ Speer Reloading Manual Number Ten (1979), p. 182