Ackley Improved case life

[seantheaussie]

What is it about AI that requires less neck trimming? Is it the sharper shoulder? Is it the loss of taper? Is it both?
Just wondering
Sean

[woob614271]

Combination of both, SeantheAussie; Case life should be close to double the parent case, and it'll need less frequent trimming during its life too..

[Ned Kelly]

G'Day All,
with any brass case, when under pressure, especially high pressure ( ) The brass WILL flow/extrude along the chamber towards the muzzle. This is particularly noticeable with highly tapered cases and high chamber pressures i.e. 22-250 at max loads.

By reducing the case body taper and increasing the shoulder angle to around 40 deg, the tendancy for the brass to flow/extrude towards the muzzle, is greatly reduced but not stopped. This was Mr Ackley's process to increase powder capacity/performance and stop case lengthening..............all good for us shooters!

hope this helps

Cheerio Ned

[seantheaussie]

Thanks fellas

[Rinso]

This was Mr Ackley's process to increase powder capacity/performance and stop case lengthening.

You do need to remember that AI conversion gives marked improvement in some cases and very little in others by way of performance.

cheers
Rinso

[Dr G]

[You do need to remember that AI conversion gives marked improvement in some cases and very little in others by way of performance.

What is the concensus on which cases show better performance post Acklecising?

ie you hear a lot about 22-250AI, 243AI and 30-06AI, are these significantly better performers than the standard parent case?

Also I would be interested to hear peoples thoughts on what makes a case more likely to perform better post AI.

[woob614271]

P O Ackley's own work on this focussed on the more tapered parent cases; e.g. 250 savage, 22.250, 30.06 and so on.
His books (if you can borrow some) are a great read.
I have the old soft-cover versions (very well thumbed!) id someone wants to bortrow them, as long as they come back, of course!

[Dr G]

Woob I would love to have a look at them and more than happy to cover postage. PM me the details if this is ok.

Cheers mate

Dr G

[Brad Y]

Dr G,

I have my 22-250 standard at the moment. Im loading 35gr of AR2206H with a 55gr vmax in remington brass. Prior to loading, I trim the cases to 1.904 and after firing they measure out to 15 thou longer. This is almost a max load, but is accurate. Since I have to trim every time you can imagine how much brass is flowing and is being lost each load from continually trimming. The cases soon end up in the scrap bin from loose primer pockets and cracks. I know the primer pocket issue might not be fixed by the Ackley improving job but i know my cases should last a bit longer. Just thinking about the lack of brass that I will have to trim away makes it seem worth it to me.

Mine is getting reamed while im in africa over the next few weeks. Will post up the results when i get back and fireform some brass.

[macca]

DrG ,this a rough extract from some old info I was given(Woob would be able to check its accuracy).
Each comparison was based on loads available in Ackleys time bar the 6.5x55 which was done in the 1990's.
6.5.55mm 140gr 13.7% increase in velocity.
30-30 150gr 12.9%
7x57mm 150gr 12.8%
300H&H 180gr 11.1%
257 117gr 9.4%
7mm-08 140gr 5.9%
220 swift 50gr 5.9%
6mm Rem 75gr 5.9%
22-250 55gr 4.6%
260 Rem 140gr 4.3%
The 270,25-06,243 280Rem and 30-06 all fall between 7 and 8%.
The loads are specific to particular projectiles and the age of the testing.
The extended case life is one of the biggest pluses as they can usually(underline usually) go ten to twenty reloads without a trim.
Have a good one,
Macca

[Brad Y]

The extended case life is one of the biggest pluses as they can usually(underline usually) go ten to twenty reloads without a trim.
Have a good one,
Macca

10 to 20 loads without a trim! See I cant even get two before i need to trim.

Thats why im getting it done.

[Dr G]

Thanks Macca, thanks Brad