Richard H Davis
Jan 15 2008, 16:49
I have decided to start reloading again and have no dies and am considering loading for the .308 Improved cartridge. i have read that factory ammo will shoot fine in it and that if i only have the .308WIN 40 degree dies, i could reload them for longer case life and longer barrel life. My research indicates that the factory ammo shoots very accurately in an improved chamber. So i guess my question is, has any body else tried this cartridge. I am not trying for greater velocity or match the .300WM for performance, just trying to get more out of my cases and barrels. Thanks
For the most part the 308 is already pretty close to improved. The 40 degree shoulder will some what limit the amount of brass creep, and may lead to longer brass life. The thing is, with proper treatment of brass you can already get 20+ reloads from quality brass such as Lapua. Of course you need to keep pressures sane, and you will need to anneal the necks ever so often (3-5 reloads between anneal sessions). I run a 6.5x55 Swede Ack. Imp. now days so you are "preaching to the choir" as the old saying goes. But 308 is one of those rounds I would not try to Imp
If you do the Imp then by all means have fun with it, there certainly is nothing wrong with having an Ackley in the shooting line!
Jan 15 2008, 22:11
So what are the velocity differences between the ackley 308 and standard 308? I was curious if there was and ackley improved 308 made yet.
Jan 16 2008, 10:23
You can "Ackley Improve" nearly any round by removing the body taper and changing the shoulder to 40 degrees. On some rounds it makes good sense, like .35 Whelen and .338-06.
Basically, by going the AI route, you end up with slightly added case capacity (insignificant in some rounds), but the sharper shoulder adds markedly to headspace control, which improves extraction and reduces case stretching.
I hear that Remington is supposed to "legitimize" the .280 Ackley Improved. I relaly like this round and would like to see it. It nearly reaches the 7mm RemMag, but with higher mag capacity in most rifles, mag loading is easier, bolt manipulation is smoother, ammo is lighter and more compact, and significantly less recoil.
Jan 16 2008, 12:19
The .308 Win/7.62x51 has a 20o shoulder. The long slope is designed to promote smooth and reliable feeding in the auto's and semi-auto's that form it's roots.
As pointed out above, the "Ackley-izing" of a cartridge will move the shoulder to 40o, decrease body taper and increase shoulder diameter.
IMHO/FWIW, as an owner of a .30-06 AI (of dubious value), I'd agree with Gary and suggest that it's really not worth doing this to a .308 either. While the .308 does stand to see a little more improvement than the .30-06, the added costs and aggravation quickly offsets any benefit. Realistically, the benefits are as outlined by Gary, less case stretch/longer life being the only thing that is really tangible. Velocity improvement MIGHT amount to 150 FPS with *some* bullets, and so, in practical terms, you've simply made a .308 into a short .30-06 . . .
"Only having .308 40o dies" means actually buying the correct .308 Ackley Improved dies, and by virtue of being custom, these are pricey and hard to find. A normal and commonly available .308 die, with it's 20o shoulder, will "un-fireform" your cases if you ever used it, and due to the reduced body taper/larger diameter at the shoulder, it cannot even be used to neck size Improved brass. The .308 AI dies (RCBS) are available special order through Huntingtons, but these are priced per request and I'd bet they're $100 or more for a standard F/L set. I don't think Redding makes them. Lee will custom make dies for you, but they too will run close to $100 if they've got the setup done, and if they haven't done them yet and need a set up charge, MUCH more. You might get past this by finding a used set.
Clymer doesn't make a reamer for it, though your 'smith may have one or another reamer company might stock them, they're understandably not much in demand . . .
There will be a velocity loss or 50-100 FPS or more in the already ballistically challenged .308 when ammo is formed from regular ammo. This is due to energy lost to the work of moving brass, as well as the increased combustion chamber volume vs. the unchanged powder charge weight.
While your information that fireforming accuracy is fine with OEM .308s is valid, the velocity loss/greater drop and typical change in base zero means these original configuration loads used for fireforming cannot use the same trajectory data, and often not the same zero, and so must be treated like the different loads that they actually are.
Fireforming for the sake of fireforming is a big PIA, yet must be done before ANY benefit is realized. By the time we invest in a set of components to fireform, we could have had a .300 WSM
Barrel life, while less an issue in a .308 than many other cartridges, will be shortened by shooting ammo that will not perform even as well as the .308 original loadings. Even if the less-than-satisfactory, and less-than-complete method of using cream of wheat or other filler over a fast-burning pistol powder is used, powder and pressure (both needed to fireform by any method) is really what causes barrel wear, not bullet friction. With your fully formed cases and added velocity, you get added bore erosion, and your barrel life will no longer equal the average .308, so any perceived economy of the .308 is just that: "perceived".
Once you've bought custom dies and fireformed a batch of brass, you'll be ready to move forward, enjoy greater brass life, and equal the ballistics of a regular .30-06, with the only "advantage" of still being in a short action rifle. Definitely with less aggravation, and probably less expense, you could be in the same short action with a .300WSM and see a **real** performance difference.
I learned my lesson and formed this opinion based on my experience with my .30-06 AI. I like the rifle - it shoots well and it IS something different, and I am "very close" to .300 WinMag ballistics with some bullets, for the less cost and aggravation I could be shooting a .300 WinMag and not wasting time/effort/money fireforming to achieve or almost achieve ballistics of an existing cartridge.
Richard H Davis
Jan 17 2008, 13:02
Gentlemen- excellent information. Finding a reamer as pointed out in one of the posts, is a big pain. Cost for dies are pricey too. i found a quote from Parker Ackley saying he never developed a .308 AI because the design was near perfect and it just wasn't worth the hassle to change it. So, many thanks for the great repsonces to my very first post. Richard :-))