Consider a makeover for that .30-06 rifle, says Thomas Tabor
When the .30-06 Springfield first appeared on the scene in 1906 (hence the ‘06’) it quickly became recognised for its abilities as a good choice for hunting, military use and even some competitive shooting events. But in all honesty, when compared to some of the choices of today, this cartridge has lost a great deal of its original lustre.
One of the first major challengers to the .30-06’s favourability arrived in 1960 when Norma introduced its revolutionary new .30 calibre magnum – the .308 Norma Mag. Three years later Winchester ramped up that competition even further by introducing its own slightly more powerful magnum in the .300 Winchester Mag and, almost immediately, shooters worldwide began to recognise how they could benefit from the far better ballistics of those two cartridges.
But almost equally important as those improved ballistics was the fact the overall cartridge length of both new arrivals were close to the .30-06, which made them acceptable for use in a standard-length bolt-action rifle. Standard-length bolt-actions are generally much cheaper to buy than the longer magnum actions, and the end of World War Two brought a glutton of surplus .30 rifles which could be customised and rechambered for these new magnum cartridges.
But even before those Norma and Winchester Magnums appeared on the scene, there was a lesser-known competitor out there. P.O. Ackley was possibly the most prolific cartridge experimenter of his time and had been diligently working on his own more powerful .30 calibre version. Like Norma and Winchester, Ackley thought if he could find a way to send a bullet out the muzzle a little faster than the ’06 could, it would result in flatter trajectories and higher retained energies on impact. His wildcat .30-06 Ackley Improved did just that by only expanding the .30’s factory-made cartridge case.
Ackley’s approach took the form of first recutting the rifle chamber to slightly larger dimensions, which included a straighter case wall and considerably sharper 40-degree shoulder angle to increase its powder capacity. Once this was done he fired the original .30-06 Springfield ammo in that new chamber, which resulted in blowing the case out to match those new specifications, a procedure commonly known as ‘fire-forming’ the brass. Once the cases have been reformed in this manner they can be resized and reloaded using handloading dies which match the new improved dimensions.
The .30-06 Ackley Improved
Ackley developed his .30-06 Improved in the 1940s and it remains one of the more popular non-commercialised wildcat cartridges today. And you can take full advantage of its more desirable ballistics by simply having a .30-06 rifle rechambered to those dimensions. While various gun writers have said the conversion from a standard .30-06 to the Ackley Improved results in an increase in powder capacity by about five per cent, my research shows a somewhat greater expansion in volume. I believe at least some of those writers were using water as a medium for comparison purposes and I don’t believe water is the most appropriate and reliable measuring method.
I’ve found in many cases water tends to underestimate capacities which might be due to the tiny air bubbles that persistently cling to the inside walls of the cases. My personal preference is to use either fine grain cartridge powder or granulated table salt. When filling cases I continuously tap the side of them with a small metal spoon to ensure a complete settling of the contents. In this case the result showed the standard .30-06 held 99.3 grains of table salt and the Ackley case 107.7 grains, an impressive total percentage increase of 8.4 per cent.
This rise in powder capacity of the case brings about a potential substantial increase in its velocity, though clearly extra powder alone doesn’t always equate to better overall performance. Every barrel is unique and a balance must always be struck between velocity and an acceptable degree of accuracy. Nevertheless, I’ve enjoyed great results in my own shooting of the .30-06 Ackley Improved over those of the .30-06 Springfield.
Handloading the Ackley
My personal experience handloading most mid to large-sized magnum cartridges have shown a real preference for slower burning-rate powders and the .30-06 Ackley Improved is no exception. My best recommendation when working up an acceptable load would be to avoid all the slower burn-rate rifle powders entirely and concentrate only on the two or three slowest rate. When working up an acceptable charge for any cartridge you should always start low then gradually increase the charge, staying alert to signs of developing excessive pressures.
Sourcing loading data will be a bit more challenging with any wildcat cartridge, though I found data for my own .30-06 Ackley Improved in some older reloading manuals as well as in book Cartridges of the World book. There’s also reloading data available on the internet but ensure anything you choose comes from a trustworthy source and, if possible, confirm it with at least one other.
Benefits of improvements
One of nice things about improved wildcat cartridges is not only can you fire them, you can also safely substitute pre-modified commercial rounds too. Even after the chamber has been recut to the new dimensions, there seems to be little problem continuing to fire the parent .30-06 Springfield rounds in that newly rechambered rifle. In this case, if you run out of handloaded Ackley ammo, the flexibility of being able to substitute Springfield .30-06 shells can be a great asset – just head to your local gunshop and buy a box.
Ackley vs belted mags
While most .30-06 bolt-action rifles have the capability to be rechambered to .300 Win Mag or .308 Norma Mag, those conversions can be more costly and in some cases a bit more problematic. In addition to having the chamber recut, a bolt face alteration is necessary to accommodate their belted designs. In some instances there may be feeding issues but these problems don’t exist when converting an 06 to the Ackley Improved design – and of course there’s no option to shoot original 06 ammo in those rifles.
Even though some handloading data indicates velocities produced by the .30-06 Ackley Improved are on par with those of the .308 Norma Mag and .300 Win Mag, I believe the Ackley falls just a bit short in those comparisons. While there are many variables which can affect such a comparison, I feel the following would be a general assumption of what a shooter can expect. By carefully selecting your powder and charge weights, it wouldn’t be unrealistic to expect an increase of up to about 150fps in muzzle velocity when shooting either 180gr or 200gr bullets with the Ackley design over the .30-06 Springfield. And when a comparison is made between either the .308 Norma Mag or.300 Win Mag firing 180gr bullets, I’d expect the .30-06 Ackley velocity to be about 100-150fps less.
The way I see it
While I’m not a huge fan of the .30-06 Springfield, I love the various .30 calibre magnums and that includes the .30-06 Ackley Improved. During many years of shooting I’ve converted several 06s to .300 Win Mag and owned at least one .308 Norma Mag. I’ve also played around with various wildcats and very much like the option of rechambering a standard .30-06 to the more desirable Ackley specs and ability to fire both type of shells in the same rifle.
Reamers for the Ackley conversion seem readily available from many suppliers, as are reloading dies (my own came from RCBS). So if you’re looking to increase performance of that old .30-06 which has seemingly taken up permanent residency in your gun-safe and not had a bullet down its barrel in a while, an Ackley makeover might be on the cards.