284 Winchester AI?

[Tac-O]

Have you seen the PCM carbide neck-up mandrels? I got one to go from .224 to .243, they can also grind to a custom taper if you need it.

Made a big difference in my case prep, seems like the die moved the shoulders back better without the ball in it doing the initial neck up. After I ditched the ball I was using a .243 steel mandrel before the carbide and the carbide does run smoother IMO.

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I haven't! I'll have to check it out. With the straight 30-284, I was using a Lyman M expander on 284win Peterson brass and that worked well.

I'm mostly referring to the fireorming being a pain. I don't turn necks and didn't experience donuts on the 30-284.

 

[ENGUNEER]

Anybody ever develop an Ackley improved version of the 284 Winchester in any caliber? I'm thinking about blowing out the shoulder to 40 degrees, blow out some of the taper in the case and then beck it down to .277 to use some of the newer .277 projectiles. Max coal would be somewhere around 3.2" to fit nicely in my medium action. Any body ever do anything similar? Any performance reports?

Go for it. I have a 284 Shehane (an improved version of the 284 Win) and I love it. It has near 7mm RM ballistics when loaded long (3.2") and is super accurate. A 270-284 improved round should give a fast, slippery, and accurate round. Enjoy the process!

 

[Alibiiv]

According to this (https://loaddata.com/Cartridge/270-284-PO-Ackley-Data/6908) you will be on par with .270 Win in a SA.

With those numbers a .270 WSM might be a better choice and a lot less work, or.....a .270 Ackley Improved and beat those numbers all day long; but in a long action. Or....if insistent on a short-action .270, a .270 WSM with a 1:8 twist barrel.

 

[jacob_strass]

With those numbers a .270 WSM might be a better choice and a lot less work, or.....a .270 Ackley Improved and beat those numbers all day long; but in a long action.

I have been debating on going for a 270 Sherman shortmag or 270 Sherman max instead of going through the whole wildcat process. It would be a lot simpler and easier and might have better performance.

 

[FEENIX]

With those numbers a .270 WSM might be a better choice and a lot less work, or.....a .270 Ackley Improved and beat those numbers all day long; but in a long action. Or....if insistent on a short-action .270, a .270 WSM with a 1:8 twist barrel.

Correct, but the OP wants to explore the wildcat possibilities of standard bolt face (.470"+/-) in SA, the .284 Win cartridge in particular.

 

[FEENIX]

I have been debating on going for a 270 Sherman shortmag or 270 Sherman max instead of going through the whole wildcat process. It would be a lot simpler and easier and might have better performance.

There is always something rewarding about having your "own" wildcat design. I am working on my 2nd own wildcat design.

 

[Alibiiv]

Correct, but the OP wants to explore the wildcat possibilities of standard bolt face (.470"+/-) in SA, the .284 Win cartridge in particular.

Yup I got it "now"!! I can read, sometimes too fast and not enough. Thank you for bringing that to my attention

 

[FEENIX]

Yup I got it "now"!! I can read, sometimes too fast and not enough. Thank you for bringing that to my attention

Believe me, I wanted to suggest differently, but I also understand the joy of having your own wildcat design regardless of what others think. Situations as such are why I never ask what rifle to build or buy.

 

[Mike Matteson]

It looks like you presently have 284. If not look at a 280AI case and neck it down to .277. The 280AI case is longer than the standard 25/06, 270, 7mm, and 30/06 case by about .1th. It will add additional powder room. 280AI cases are built by Peterson, and not sure of others. So it's an easy neck down on the case. You can get Redding bushing FL dies, that are on the market place. just need bushing to size down the neck. You can get a LE Wilson Micro Seater Blank and use the reamer to set it up. I believe you will need an Arbor Press to set the bullets into the cases, I believe. Or at lease that's what I have set up for a 6mm/280AI rifle. I looked at all types of case sizes to make that choice. I don't have experience on 284 cases, so I can help you there.
I am looking at have a 25/280AI rifle built.

 

[STGguy]

Yes it's called a 284 Shehane as someone else pointed out.

The 284 case is already pretty efficient, compared to say the older more case tapered and gentler neck / shoulder angle ms like a 30-30 win or 22 hornet etc.

That being the case, you really don't get that much more out of the 284 for all the hassle - reamer , foreforming , custom dies etc etc

I saw an article either by or based on PO Ackleys work and if I can find it I'll post it .

It's interesting and lists the best and worst cartridges to "Ackleyize"

 

[BillLarson]

Improving the 284 will likely gain only about 6% at best. It's already pretty maxed out for case design?

There are at least 6 wildcats on the factory 284 case.All are an improvement ballisticly.When you steppen the shoulder you get feed problems...

 

[jacob_strass]

Yes it's called a 284 Shehane as someone else pointed out.

The 284 case is already pretty efficient, compared to say the older more case tapered and gentler neck / shoulder angle ms like a 30-30 win or 22 hornet etc.

That being the case, you really don't get that much more out of the 284 for all the hassle - reamer , foreforming , custom dies etc etc

I saw an article either by or based on PO Ackleys work and if I can find it I'll post it .

It's interesting and lists the best and worst cartridges to "Ackleyize"

I thought the shoulder angle stays the same on the shehane? I might be wrong but I just thought the shehane took some taper out and that was it.

 

[FEENIX]

LOL! The .284 Win is already an efficient cartridge, yet Shehane was able to squeeze in more efficiency. A 75-100 FPS or ~6% gain on the hands of an accomplished reloader and wildcatter might be good enough reason. Our venerable .30-06, an argument to AI it can also be made if it is worth the trouble. If the end-user is willing and able to invest in time, effort, and money, yes, just like @Tac-O's new project. I appreciate all the wildcatters for thinking outside the box.

I originally was going to go AI but had my .30-06 rechambered to .30 Gibbs, and I am pleased with it.

I also have a .270 AI. I originally was going to build a .280 AI, but everybody in their brother has one. I only know a handful of .270 AI and .30 Gibbs owners here. @jacob_strass, good luck with whatever you decide on your build. Cheers!

 

[FEENIX]

There are at least 6 wildcats on the factory 284 case.All are an improvement ballisticly.When you steppen the shoulder you get feed problems...

I am interested in hearing if any of the .284 wildcat owners have any feeding issues, especially those with DBMs. I have 35° and 37.5° (and soon 45°) using DBMs without feeding problems thus far.