284 Winchester AI?

[jacob_strass]

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?

 

[Plowboy85]

I like the idea, is this driven by the use of lapua brass? Seems like it would be on the heels of the 270wsm.

 

[jacob_strass]

I like the idea, is this driven by the use of lapua brass? Seems like it would be on the heels of the 270wsm.

Definitely would like to use lapua or Peterson brass for this.

 

[FEENIX]

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?

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

 

[just_jon]

Found some data on the unimproved version of the 270-284 Win. I like the idea, but would not expect to see an increase of more than 75-100 fps by improving this round given the 284's current shoulder angle of 35 degrees. I shoot a number of AIs and while most provided substantial performance gains (250 Sav AI, 257 Robt AI and 280AI), others such as the 22-250AI and 35 Whelen AI fell short of my expectations.

270-284 WINCHESTER

 

[jacob_strass]

My thought with the AI is that 270-284 is already a custom reamer, why not blow out the shoulder and taper while your at it?

 

[QuietTexan]

If you're trying to mag feed you're already fighting the rebated rim, would taking out the taper make the bolt more likely to skip over the rim?

 

[just_jon]

My thought with the AI is that 270-284 is already a custom reamer, why not blow out the shoulder and taper while your at it?

I failed to consider that.

 

[GLTaylor]

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

 

[Tac-O]

My thought with the AI is that 270-284 is already a custom reamer, why not blow out the shoulder and taper while your at it?

Because you'd have to fireform and you're not gaining much.

BUT a lot of the competition guys swear by the 284 shehane, so that's got to be worthwhile for 270 also, so why not just do 40* shoulder also?

I am doing a 30-284 with 40* shoulder and blowing sidewalls out like a shehane. I'm just waiting on the reamers. Yes it will be a pain to prep brass, but it's a what I wanted to do.

@Taylorbok is doing a 284 shehane w 40* shoulder. He just got his reamers.

If you don't mind firefirming or getting a hydroform die, I'd say do it if you want to! I bet that case in a 270 would be the bees knees and there might be 1 other guy in the world shooting it

 

[QuietTexan]

Yes it will be a pain to prep brass, but it's a what I wanted to do.

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.

30cal FROM 6mm Carbide Neck Up Mandrel (.307")

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[FEENIX]

My thought with the AI is that 270-284 is already a custom reamer, why not blow out the shoulder and taper while your at it?

Do not let anybody including myself talk you out of your wildcat plan. Good luck!

 

[VinceMule]

I have been a wild cat freek in my life. Today's world is a very different place.

First, on any wild cat project, this now gets very, very expensive with long waits. Dies are a significant issue, and C4HD is an excellent place to start. You may have a year's wait or more. The chambering reamer could be used to ream out the bullet seater and comp neck sizing dies on the Redding 284 Competition set, but the Full-Length sizer is a real bugger to deal with. You can not make a full-length sizer from a chamber reamer.

I don't know if there would be much gain in the 284 AI to warrant the expense and aggravation.

The std 280 AI using Lapua 30/06 brass, R#26, and IMR 7828 with 180g ELDM, 180g Berger hunting, and 175g Nsoler long-range accubonds is very impressive.

Also, in a custom rifle, the 7 Mag with Brux 28" 9T shoots the 162-168g bullets at 3100 with Retumbo and 215's, and 175-180g Bullets at 3030 with R#26 with bug hole accuracy.

Wild cat tooling, dies, are just a pain to deal with at this time, and Expense is simply out of this world.

I am trying to find dies now for a 260 AI, there are NONE available...simple cartridges,and I have a reamer, barrels, 243 comp seater, and comp neck sizer to make into the 260 AI, but no full-length sizer. If I order a "die reamer" then you have to deal with heat treat...not going down that road.

 

[Tac-O]

OP, I would recommend getting a FL sizer reamer with your chamber reamer.

The cheapest way the make your dies might be the following. I can't say for certain, but it's what I am doing and is more affordable. Keep in mind, I'm not a competitor and I shoot for fun and hunting. I am happy if I can keep a consistent 0.5-0.75moa load going.

Die blank from PTG fr a FL sizer. Then you can either get some type of expander ball stem to have threaded in the top, or get an expander die. I have a Lyman expander die. It's the cheapest option I found and you can get custom sizes for it through buffalo arms company.

For a seater die, use a Lee 270win dead length seater and use the chamber reamer to open it up. Shorten the length appropriately. The Lee dead length rifle seater is not hardened.


Other options are newlon die blanks or having custom dies made. Having dies made by a die mfg means you may not get to pick dimensions exactly, and longer wait if using fired brass.