243 AI to 22-243 AI

[Blueman]

So I have a bunch of lapua 243 AI brass and I want to build a 22-243 AI. Last night I tried to use a bushing die and neck down to 22-243 AI and the neck pushed into the shoulder. I didn't have an intermediate sized bushing, would that help? Or is it still going to collapse? I'm looking for suggestions. Am I stuck with getting new 243 brass necking down and fireforming?

 

[jpretle]

Did you use any lube?
Intermediate bushing would be a good start.

 

[Mark W]

I do mine in one step but it takes a good outside chamfer to keep it from crushing. Lapua brass also has to be neck turned for mine.

 

[hawkeyeshoooer]

It's not that simple. A correct Ackley Improved chamber is made by setting the barrel back one thread and re-chambering so that a standard 243 cartridge is a crush fit. That is what gives the necessary headspace control while fire-forming. Otherwise the cases will stretch upon firing leading to possible seperations.

Before going ahead, think about this. The 243 Ackley Improved offers virtually no gain over the standard 243 W. The shoulder on the 243 W is already the maximum diameter so the only change is increasing the shoulder angle from 20 degrees to 40 degrees. This may look snazzy but it doesn't do much to improve the ballistics.

JMHO

 

[JamesnTN]

It's not that simple. A correct Ackley Improved chamber is made by setting the barrel back one thread and re-chambering so that a standard 243 cartridge is a crush fit. That is what gives the necessary headspace control while fire-forming. Otherwise the cases will stretch upon firing leading to possible seperations.

Before going ahead, think about this. The 243 Ackley Improved offers virtually no gain over the standard 243 W. The shoulder on the 243 W is already the maximum diameter so the only change is increasing the shoulder angle from 20 degrees to 40 degrees. This may look snazzy but it doesn't do much to improve the ballistics.

JMHO

It’s been proven though the 40* shoulder has a much better internal combustion and therefore provides a more efficient load. You do gain velocity but not really a lot. It helps though for pushing the heavier bullets.

 

[4xforfun]

Do they make a shoulder bump die for the 22-243AI? That is what I use in my 6 6.5x47L. Run 6.5 brass in the shoulder bump die and the necks are squeezed down ALMOST all of the way to 6mm. Enough so that they will easily go through a neck or FL di to finish them off. A 22-243AI shoulder bump die would do the same thing. ZERO lost cases.

It also works with my Dasher when forming brass (false shoulder method) Neck up and then run them back through the bump die far enough to put the new shoulder about where you need it.. Finish with the neck die to exact.

Tod

 

[Blueman]

Did you use any lube?
Intermediate bushing would be a good start.

Yes I tried with several amounts and types of lube no luck.

How many bushing should I try to size down?

Any other words of wisdom?

 

[jpretle]

As suggested previously, you might also try a heavy outside chamfer.
Is your brass recently annealed?? If so, it might be a bit soft for the neck down.

 

[fredo]

You may be crushing those .243AI cases due to them being 'work hardened' from initial fireforming, and subsequent use/abuse. How many firings do they have on 'em???

To that end, I'd recommend annealing your .243AI brass, THEN try necking down with bushing FL die. Bet ya that helps a bunch, if not alleviates your issue, altogether...

If your .243AI brass has several firing already, just leave it be, and start fresh. No sense doing the work of annealing if its only gonna get ya one or two more firings. Plus, NEW brass formed in THAT chamber always makes for a better 'fit', which makes for happiness, all around...

F.w.i.w... I use Imperial Sizing Wax on NEW .243 brass. Neck down (bushing FL die) until brass closes with proper 'crush' fit in the rifle, and go! IIRc, I roll wit a .251" bushing for Lapua .243 brass, and do it in one step....

P.S. "no gain in performance" when going to an AI is HOGWASH. Not only is the capacity gain measurably increased, the performance is elevated, with respect to both case life, and outright velocity improvement...

Feel free to PM, as I'm a big fan of the .22-243AI, happy to help!

Have fun!!!

 

[Savageseven]

what seating die are you using for 22-243 AI ??

 

[Savageseven]

what kinda velocity did you guys get with the 22-243 AI with 75 grain bullet ?

 

[Oso]

Similar advise as Fredo. If the 243AI brass has been shot a few times then anneal the cases to improve the ability to reshape the brass. Chamfer the case mouth and use imperial wax on the cases.

1) resize the brass with the 243AI die (internal components removed (no expander ball)
2) resize using the 22-243AI (internal parts removed) in a series of incremental steps (down a little and then back-off to allow any trapped air to escape, repeat). Make sure to measure final shoulder bump/placement.
3) Resize using the 22-243AI with the expander ball inserted or use an Expander Die & Mandrel to achieve proper neck tension and ID uniformity.