.280 AI vs .284 Winchester AI...

[BlackKnight755]

I want to build a new long range rifle and I am looking at the .280 Remington ackley improved or a .284 Winchester ackley improved. I need to know if the .284 has/can be made? Also which one has the largest case capacity? If I am reading correctly, both are .284 and the BC is out of this world for that cal. Berger states .617 and .659 for the VLD's that I want to use. If anyone cares to, please share what ballistics that I can expect from both cartridges. I will be shooting a 32" Broughton 5C barrel so I should get some added FPS in the long barrel. I intend to shoot 1000 yards and farther with the new rifle. Any help will be greatly appreciated. BK

[AZShooter]

You didn't mention the action length. SA dictates you use the 284.


Is this rifle going to be a repeater or single shot? I am asking because the 168 and 180 VLDs are quite long. If it is going to be a single shot it is no big deal. Otherwise the 280 AI may require a custom action to accomodate the length and still feed from the magazine. For optimal performance with either case you should consider a custom reamer.


There is an improved version of the 284 win called the 284 Shehane but technically it shouldn't be called an Ackley Improved. Bill Shehane designed the case's body-taper a bit larger about .010", but didn't change the shoulder angle from the original 35 degrees. It is supposed to add around 3.35 grains of powder. I have a friend who made one for long range shooting and said it wasn't worth the effort. FYI just by using RL-17 you can gain more velocity over the usual H4831 and 4350s.

As for the 280 AI I cannot tell you as much as I am not familiar with it. Perhaps someone else can add to this thread.

Here is a link for some reading about the various short action 7mms:

7mm Cartridge Guide

[BlackKnight755]

Originally Posted by AZShooter

You didn't mention the action length. SA dictates you use the 284.


Is this rifle going to be a repeater or single shot? I am asking because the 168 and 180 VLDs are quite long. If it is going to be a single shot it is no big deal. Otherwise the 280 AI may require a custom action to accomodate the length and still feed from the magazine. For optimal performance with either case you should consider a custom reamer.


There is an improved version of the 284 win called the 284 Shehane but technically it shouldn't be called an Ackley Improved. Bill Shehane designed the case's body-taper a bit larger about .010", but didn't change the shoulder angle from the original 35 degrees. It is supposed to add around 3.35 grains of powder. I have a friend who made one for long range shooting and said it wasn't worth the effort. FYI just by using RL-17 you can gain more velocity over the usual H4831 and 4350s.

As for the 280 AI I cannot tell you as much as I am not familiar with it. Perhaps someone else can add to this thread.

Here is a link for some reading about the various short action 7mms:

7mm Cartridge Guide

Thanks for the input AZShooter,

I intend to use a long action that I have. I will be using the rifle as a single shot by installing a removable follower.

I have read about the .284 Shehane and when I go to the expense, I will have a reamer made in the Ackley Improved. I will have custom dies made also.

I have a .280 AI in a hunting rifle setting that does real well. It has a much shorter barrel, 26", than I want for my target rifle but it still holds up at 1000 yards. I think that one reason that I am interested in the .284 Win. AI is because of the performance that I have seen in the .280. I am thinking that with the possibility of more case capacity, thus comes more velocity and being able to capitalize on the high BC of the .284 bullets.

Can someone tell me the case capacities on both cartridges. If you only know one please post as someone else may know the other one.

Thanks again and keep the posts/comments coming! BK

[Trickymissfit]

first of all there is no such thing as a .284AI, but it needed to be done. Ackley almost always used .010" taper per inch with a 40 degree shoulder. You already have a 35 degree shoulder, and a similar amount of taper. The best thing that could happen to the case is to shove the shoulder back about .06" to give the bullet something better to seat in. Plus it totally keeps the flame path inside the neck to promote a better barrel life. I think you'd be better served with the .280AI if your planning on the use of very long bullets. Of course you could also use a 7x57AI and get virtually the same results as with the .280AI. These rounds will fit the magazine better also

Also note that a 26" barrel is about the max length you'll ever need in the 30-06 case. You'd probably be just fine with a 24" barrel, and group a little more consistently.
gary

[BlackKnight755]

Originally Posted by Trickymissfit

first of all there is no such thing as a .284AI, but it needed to be done. Ackley almost always used .010" taper per inch with a 40 degree shoulder. You already have a 35 degree shoulder, and a similar amount of taper. The best thing that could happen to the case is to shove the shoulder back about .06" to give the bullet something better to seat in. Plus it totally keeps the flame path inside the neck to promote a better barrel life. I think you'd be better served with the .280AI if your planning on the use of very long bullets. Of course you could also use a 7x57AI and get virtually the same results as with the .280AI. These rounds will fit the magazine better also

Also note that a 26" barrel is about the max length you'll ever need in the 30-06 case. You'd probably be just fine with a 24" barrel, and group a little more consistently.
gary

Gary,

Thanks for the reply and suggestions. Do you not think that the longer barrel, 32" would be beneficial when it comes to more FPS? I have a 6.5x284 with a 32" broughton 5C on it and I shoot through the chronny almost 100 FPS faster than my friend and his shorter hunting barrel. His is a 24" broughton 5C. We shot the same exact load for the test, and I KNOW that mine is more accurate than his especially at anything over 600 yards. Also OAL is not an issue as I will be single feeding the ammo, it will never see the inside of a magazine.

Thanks again for the reply, BK

[BlackKnight755]

... Ok, It has been said that there is no such animal as a .284 Ackley Improved. My next question is, can one be made and if so who could I get in touch with to see what I would need to do next? I know that I'm not inventing the wheel and I am sure and positive that I'm not the first on to think about the .284 as an Ackley Improved cartidge right?

[AZShooter]

Anything can be done all it takes is money. Talk to Dave Kiff at Pacific Tool and Gauge he'll make you that custom reamer. I think you are going to encounter some serious costs for a tiny bit more velocity. I'd opt for a 32" barrel and a standard 284, which is going to give you good performance or go with a larger case like the 7 WSM. All you would have to do is open up the bolt face. No custom reamers or fireforming.



Read what these guys did with the standard 284:

Record-Setting .284 Win F-Classer

NBRSA 1K Winner Jerry Tierney

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A couple of 7 WSMs

Vince B's 7mm WSM Record-Breaker (7 Win Short Mag)

7mm WSM -- High-Country Hunter