Site hosted by Angelfire.com: Build your free website today!

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

 

 

 

 

 

 

 

 Warning: Loads used were carefully worked up in one particular rifle and may not be safe in other rifles. Moly plated bullets were used in most loads, the use of non plated bullets could dramatically increase pressures to unsafe limits.

I used the 700 X shotgun powder with the NECO fire Lapping kit in some factory barrels. It produced a much smoother barrel. It did however wash out the throat by more than a 1/4 inch. If fire lapping is on your agenda it should be done before the new chamber is cut with the standard 280 Remington case.

If the 280 Ackley is a conversion from a 280 Remington the barrel should be set back at least a 1/2 inch to remove the old throat and chamber neck.

The fire-lapping grit should not be applied to the ogive of the bullet, if it is to be done to a barrel that is not going to be rechambered. I have only fire-lapped two barrels and have only limited experience with the process. I do know it is very time consuming and laborious.

175 gr

Speer

14.0 gr

700 X

 

1300

 

New Barrel August 1, 1999.

Loads below were fired in a brand new bench rest grade Sporter weight SS. barrel by Gailard 25.5 " long with a 1-10 twist. The rifle has the same specs as above except chamber length, which is 2.530" instead of the usual 2.555 to be compatible with my fire forming method. The throat in this barrel 0.200 and is shorter than the previous one and designed with the 139 and 140 grain bullets in mind which seat flush with the bottom of the neck. I may lengthen the throat by 0.100". The previous Hart barrel got accidentally bent :-( and was replaced with a Canadian made Gailard  barrel. I hope this barrel will shoot as well as the Hart.

All Loads with Reloader 22. 139 gr Hornady and 140 Nosler Ballistic tip all loads in Series of three rounds. Note: All bullets are Moly plated.

Load#

Grains

Base before

Base after

Velocity

Group@112yrds

Notes

1

62.0

.4682

.469

3059

1.25

Hornady 139

2

63.0

.4688

.4697

3149

" "

" "

3

64.0

.4688

.4693 max

3209

" "

94.6% L.D.

4

62.0

.4687

.4690

3085

1.00

Nosler 140 BT

5

64.0

Reduce 0.5 gr

3306 av. 6

0.50"

120 gr V-Max

6

58.0

2757 av. 6

1.25

175 gr Rem

7 new

63.0 IMR4350

Too Hot

Reduce 1.0 gr

120 Ball Tip

8 new

63,0 IMR4350

Too Hot set .020 off land

Reduce 1.0 gr

Very poor

120 gr Barnes x

9 new 12/11/01

62.0 IMR4350

120 Ball Tip

10 new 12/11/01

62,0 IMR4350

120 gr Barnes x

11 new 12/11/01

62.0 IMR4350

120 gr V-max

12 new 12/11/01

61,0 IMR4350

139 Hornady

13 new 12/11/01

61,0 IMR4350

140 gr Ball.Tip

 

 Jan.15/01 Tested 6 loads 175 gr Rem Semi Pointed and 6 loads 120gr Hornady V-Max. No particular care was taken too shoot good groups, while using the Chronograph to record the below velocities. But I expected better. 64.0 gr of Reloader 22 represents a loading density of 94.6 % and no signs of excessive pressure. Reloader 19 is also a good powder for this weight of bullets and will be tested next

 Building a good 280 Ackley improved is easy enough, and your pocket book is the only limiting factor.

The Remington 700 action is an easy one to accurize and to buy. The Remington laminated stocks are good and very stable. Remington barrels are not my favorites, but some are not too bad. Depends on what you can afford a new barrel should at least be considered with a custom chamber.

If the rifle shoots well with the standard chamber and barrel, it will shoot well with the improved chamber, if the job is done right. For an exceptional hunting rifle my specifications are as follows.

The Ackley Improved cartridge is not a super do all and some claim greatly exaggerated performance.

In spite of this, the cartridges are a dream to hand load and cases last for a long time with proper care and intelligent loading practices. With so much information on the Internet a hand loader should not have any problems in producing superior performing ammo for this fine 7mm Wild Cat.

Using the forward part of the 280 Ackley improved reamer with the longer neck and the body of the 243 Ackley Improved reamer is another dream for a sore shoulder. The chamber dimension of the neck would be 0.311 by 0.316 long.

I would call it the 7mm SSAI and use it in a short Remington 700 Action. The brass is easy to make from 30-06 brass or 7x57. This is basically a 7mm-08 Improved with the Ackley 40-degree shoulder and a 0.311 neck length, allowing 0.005 forward chamber clearance. Please review my procedures for making long neck brass for the 243 Ackley Improved.

The 139 gr Hornady or the new 140 gr Nosler Silver Tip bullets would work fine in that set up. The bullets would slightly infringe on the powder room with a total cartridge length of 2.800". I suggest a twist of 1 in 10". Although I have a barrel with a 1 in 11" twist that I will use. This project is at present in the development stage. My guess is that either one of these bullets will reach close to 3000 ft or more per second, using Reloader 19 powder or similar. Considering the size of the cartridge, that is not too shabby.

 You may ask why bother? Use a 7 mm-08 and be done with it. Perhaps you are right, but then you are missing 200 ft/sec, easy reloading and all the fun of having something different to talk about.

Nearly all factory cartridges are made for easy manufacturing with the military in mind, hence the long sloping shoulders. Our standard cartridges were designed to function in machine guns and automatic weapons, where empty cases are considered scrap after the first use. Improving a standard cartridge separates the handloader from the military concept, besides achieving enhanced performance and utility.

Warning: Loads used were carefully worked up in one particular rifle and may not be safe in other rifles. Moly plated bullets were used in all loads, the use of non plated bullets could dramatically increase pressures to unsafe limits.

Note: Disclaimer. The above is a description of making modified cartridge cases for my own use for a specific rifle. The above description of making modified cartridge cases and loads is not guarantied to work satisfactory in other rifles and or chambers. Its use could result in bodily harm by unqualified producers with unsuitable tools, firearms and materials. The use of the description for making modified cartridge cases is free of charge and the user of it assumes full responsibility for his or her firearms and safety. Wear safety glasses at all times when shooting and handloading

Here is a 280Rem and a 280AI link from Jonas in Sweden.

http://communities.msn.se/280RemingtonSweden

 

Please forward any comments for the above to

 

zermel@shaw.ca

 

Home Page