I down loaded this from another site.This guy strikes me as careful and well reasoned handloader and 280AI user.Unfortunately when I downloaded the article not all the data came up, but IIRC from 3 minutes ago, he topped out at 3250 with a 140 gr bullet and a flat 3000 with a 160.
Note his comments about the 280AI being a "soft, unpretentious" 7 mag. Note also,his comment on water capacity of the case at 67.6 gr of water to neck/shoulder junction.I didn't do it, but compare that to a standard 280, a 7 Rem Mag,a 7mm Dakota,STW,and Mashburn.Lemme know if you care to.
Revised 03/21/02
The improved 280 Remington Case.
280AI with 168gr Berger VLD bullet
The 280 Remington Improved comes in several versions. The 280 Ackley Improved with the 40-degree shoulder is perhaps the most the common. The RCBS version by Fred Huntington with a 30-degree shoulder is more suitable for hunting with magazine rifles, for fast reloading. Although deliberate and slow reloading is recommended for either shoulder, when the magazine is used. The 30-degree shoulder creates fewer jams.
There are some very short-neck versions, like the 280 Gibbs. These versions will increase the powder capacity even more for a little extra performance, and will extract every ounce of power from the 280 Remington case. The only problem I have with these short-neck versions is that they are completely custom in all respects, including reamers, dies, and fire forming methods. But they are real performers.
Holding long 7-mm bullets concentric in a hunting type rifle with a reasonable neck wall thickness of 0.012 to 0.013" is not easy with only 0.280 or less neck length.
One version has a 0.300 neck length, which allows a 0.030" longer powder room than the standard fire formed version. For single shot rifles the necks walls can be reduced to 0.0085" or 0.009 and tend to be less obstinate. The value to reduce case necks that thin is questionable. Total bench rest techniques in reloading are mandatory to make them shoot well.
The 280 Ackley Improved and the 280 Remington Improved RCBS are basically the same except for shoulder angle. With the standard chamber and neck diameter of 0.318, the factory 280 Remington cartridges can be fired to produce the improved cases. The neck junction is set back 0.004" in the 280 AI chamber for a tight fit when standard 280 Remington cases are fired.
Fire forming will shorten the cases by 0.012" to 0.015". The common chamber dimensions are: base 0.469", shoulder diameter 0.455", neck 0.318, chamber length is about 2.555 depending on reamer maker. I prefer a length of 2.530. This length requires a special fire forming method without a bullet.
Since my chamber has also a tight neck of 0.311, virgin brass is first outside neck reamed. The neck walls are trued to a thickness of 0.0125. Most virgin brass is about 2.538" long. After all the case preparation work is done, the necks are chamfered and the cases primed and charged with 16.0 gr of 700X shot gun powder. The cases are then tightly packed with Cream of Wheat to within 1/8 of top. A dab of Crisco is used to hold the Cream of Wheat in place. Commence firing your cases. You are now ready for reloading.
Most of the time your first full power load will make the case 0.004" longer. I have used both the standard and the magnum primers and have settled on the Federal No. 210M Match Large Rifle Primers. Since my rifle is mostly for deer and antelope hunting I do experiment with different bullets in the 130 gr to 145 gr ranges. The Barnes bullets do a good job on game, but have never produced the best groups in some of my rifles.
My favorite powders for the above bullets are IMR 4350, H4831 and Reloader #22. The Norma cases I use have a water volume of 67.6 gr., filled to neck and shoulder junction. A starting loading density for the above bullets and powder choices would be 85%. Work up from there. Also I have found that IMR 4350 will show sign of high pressure before maximum velocity is reached. I most cases Reloader 22 will reach higher velocities.
Although Norma brass cases are more expensive than domestic cases, the outstanding dimensional consistency of the Norma 280 cases are in my opinion worth the extra cost. I have found that Remington cases are as much as 0.007 undersize and some with more than maximum headspace. Since all cases have to be fire formed the headspace is easily eliminated. But the bulge on the bottom can not, and will eventual allow for primer pocket expansion. These cases were made for semi auto rifles and intended to fall into the chamber.
The 280 Ackley Improved qualifies as an unpretentious 7mm soft magnum. It does not have to take a backseat to any of the medium calibers. The outstanding selection of bullets makes it one of the most versatile hunting rifles. Try it on antelope, deer, moose and elk. The two latter species require the 175-gr. bullets. Also I have killed moose with 160 gr Speer bullets.
With a bullet seated in the case the outside diameter of the case neck is 0.308. The radial chamber clearance is 0.0015" (284+12+12 = 308). Chamber neck is 0.311.
Here are some of the loads I have used and still use. These loads were fired over time in four different rifles and considered maximum in the guns I used them in. This is not a loading recommendation and should not be used in any other gun. Use your case water volume measured in grains to the bottom of neck and multiply by 0.85.
For instance 67.6 gr of water x 0.85 = 57.46 grains of powder for the appropriate type of powder, would be a starting load. The powders listed below are appropriate types for this cartridge.
Bullet Weight
Bullet Make
Powder Weight
Powder Maker
Group @ 100 yards 3 shots
Velocity estimated
140 gr
Nosler solid base
60.0 gr.
H 4831
1.00 inch
162 gr
Hornady BT
60.0 gr
IMR 4350
7/8 inch
2950
160 gr
Nosler Part.
61.0 gr
IMR 4831
3/4 inch
3000
139 gr
Hornady FB
62.5 gr
IMR 4831
3/4 inch
3250
139 gr
" " "
61.0 gr
IMR 4350
-----
------
140 gr
Nosler Part.
62.0 gr
IMR 4831
0.700 inch
3200
140 gr
Barnes- X
62.0 gr
IMR 4831
1.50 inch
----
140 gr
Barns-x
61.0 gr
IMR 4350
3/4 inch
----
140 gr
Nosler Ball Tip
62.0 gr
Reloader # 22
0.250 inch
130 gr moly
Nosler Ball Tip
60.0 gr
IMR 4350
2.00 inch
