243 AI vs 243 win improved 40°. Are they the same or what’s different?

[Mattd212]

Out of a 1:8" twist the 55s might hang together long enough to get a read on the chronograph!

Hahaha. That is definitely a concern

 

[Mattd212]

Out of a 1:8" twist the 55s might hang together long enough to get a read on the chronograph!

Currently I believe the twist is 1/9.25 and they are at roughly 4070 fps and they are hanging together well so we will see

 

[Bill Norris]

My twist is 1 - 7.5 so I would do well to stay away from the light weights. 80 gr. is the lightest I have tried and they grouped well.

 

[ggshoots]

Mine is a 9.25" twist and shoots 70's-80's really well but also shoots 100gr Sierra SP very well.
On reamers most of mine are Manson and Clymer but the last reamer I bought was from PT&G in 223AI. It cuts like butter, just awsome.

 

[Capt. Oblivious]

Fot the faster twist hang with the 70gr Noslers. You will need to try really hard to blow them up

 

[std7mag]

It's going to be neigh on impossible to find 243AI marked dies.

P.O. Ackley never did any work with the 308 family of cases.

Hence while we commonly call them Ackley Improved, they are actually Improved with 40° shoulder.

My 7mm-08 Imp 40° allowed usable capacity+.5-+1.0gr of powder.

I start with a mid charge for the parent case and go up by.0.03gr to get my accuracy node.

 

[3Ackleys]

Hey guys. I have wanted to rechamber my 243 win for quite some time now and was wanting to go to 243 ai but am having a pain trying to find dies. Have recently broke 4000fps out of the win and am wanting more.

Precision reloading has Redding dies in stock.

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I have a 9 twist and shoot 105 Bergers w/H4831 sc. at 3090 fps. You can run it up a bit, but this load shoots small. And the Lapua brass lasts a long time.

 

[3Ackleys]

It's going to be neigh on impossible to find 243AI marked dies.

P.O. Ackley never did any work with the 308 family of cases.

Hence while we commonly call them Ackley Improved, they are actually Improved with 40° shoulder.

My 7mm-08 Imp 40° allowed usable capacity+.5-+1.0gr of powder.

I start with a mid charge for the parent case and go up by.0.03gr to get my accuracy node.

On pages 303-307 of P.O. Ackleys book Vol. one, he has numerous references to the 243 Ackley improved.
He states "it is quite similar to the Mashburn version" He goes on to say "it was created by popular demand, not with the idea of improving the 243 Win. which itself might be termed an improved cartridge"

In addition to load data for the 243 Winchester Improved (Ackley),
he also lists the 243 RCBS, EPPS, Mashburn, and the Reynolds special.

 

[BobB-CapstonePG]

Here is an excerpt from an article that I wrote several years ago that is available for the .243 Win Info Page that you can access from the home page. This will give you the differences between the .243 Winchester Improved and the .243 Ackley Improved.

Different Reamers, Different “Improveds”

One thing that you need to watch for is what version of the .243 Improved that you have. This depends, for the most part, on whose reamer you will be using for the chambering of your barrel. It is easy to determine if your .243 Improved is the .243 Ackley Improved, or the .243 Winchester Improved. If you have the .243 Ackley Improved, the shoulder-body section will measure .460″ dia. at this point. If you have the .243 Winchester Improved, the shoulder-body section will measure .455″ diameter at this point. Both cartridges have the 40-degree shoulder. I have used both versions and found that you can use any data developed for either version interchangeably.

 

[bobtails]

Will these dies match what the barrel manufacture will chamber? If I get a reamer print from them do I need the shoulder area to be .460 or .455?

 

[bobtails]

Does anyone know if Redding will tell me the size of the shoulder/ body junction on this sizing die or is it a mute point since it’s a neck sizing die?

 

[Bill Norris]

Does anyone know if Redding will tell me the size of the shoulder/ body junction on this sizing die or is it a mute point since it’s a neck sizing die?

The neck sizing die will not size the shoulder/body area of the case.

 

[bobtails]

The neck sizing die will not size the shoulder/body area of the case.

But won’t I eventually have to bump that area back ??? If my thinking is correct I can take a fired case and measure it and then have a baseline line to know that after a few firing I may have to bump it back a couple thousandths ? Or would I just always neck sizing and not worry about body ??

 

[Bill Norris]

But won’t I eventually have to bump that area back ??? If my thinking is correct I can take a fired case and measure it and then have a baseline line to know that after a few firing I may have to bump it back a couple thousandths ? Or would I just always neck sizing and not worry about body ??

Personally, I would NOT neck-size at all. I would go with a F/L bushing die to begin with. At some point you will need to bump the shoulders anyway.

 

[ggshoots]

I'm with Bill. I never neck size as usually within 3 firings they get tight. I would just as soon full length size every time so its alway consistent.
Also when I tried to get Redding to send me drawings of thier dies they wouldnt do it. Now that was early covid and nobody was doing any extra work.

 

[Bill Norris]

I'm with Bill. I never neck size as usually within 3 firings they get tight. I would just as soon full length size every time so its alway consistent.
Also when I tried to get Redding to send me drawings of thier dies they wouldnt do it. Now that was early covid and nobody was doing any extra work.

Agree 100%.

 

[Uncle Bruce]

Agree 100%.

H 1000 will move the old hornady 105 A max at 3050 fps easily.

 

[Bill Norris]

H 1000 will move the old hornady 105 A max at 3050 fps easily.

So far I've run the 107 gr. Sierra @ 3283 FPS 12 E S 5 S D with great accuracy. That is an HBN coated bullet. But, I know the outcome of running them that hard prolonged.