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Old October 17, 2009, 06:47 PM   #1
davem
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30-06 Ackley Improved

Anyone opt for the Ackley Improved. Suppose to yield high velocity, lower pressure, longer case life- if you reload.

And, is there any 8mm or 38/30-06 type cartridges, maybe Ackley Improved- that are a worthwhile improvement over just the plain old 30-06? For Elk/Moose.
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Old October 17, 2009, 07:27 PM   #2
ZeroJunk
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The 30/06 improved is a good conversation cartridge anyway. You can put about three more grains of slow burning powder in it and gain a little velocity.

I have done it, not just read about it in a book.

But, in the end there is not much to be gained except having something different. Standard 30/06 is fine and if you want more velocity you can buy a magnum.
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Old October 17, 2009, 10:52 PM   #3
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There are several variations out there of the 06 cartridge. I have an 8mm-06, .338-06, .35 Whelen. The largest bullet diameter to be used in the 06 case effectively is .411 in the .400 Whelen.

All of these cartridges have been improved at one time or another. When you start going to large diameter bullets in this case the improved shoulder provides for better headspacing and becomes a necessity. However, improving the 06 case does little to increase performance over the original.
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Old October 17, 2009, 11:23 PM   #4
GeauxTide
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Elk, Moose?

.338-06. 210 Nosler at 2800fps in a 22" barrel. If you have to have an '06, screw on a 26" barrel, throated for 200gr bullets. You'll get the improved velocities with less powder. You won't have to buy the more expensive dies, fire-form brass, and other time consuming steps with custom chambers.
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Old October 18, 2009, 03:38 AM   #5
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There is an 8mm-06AI. Usually they were made on old 98's that had a good bbl and needed some chamber work. Its a pretty simple change over. As for the 06AI that is even easier.
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Old October 18, 2009, 07:27 AM   #6
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I always wondered about the "improved" claim, you trade a shoulder form optimized for feeding for a shoulder optimized for ballistic performance. If you need a certain performance on the range, there are truly modern cartridges out there, if you go hunting, 4 gr extra powder won't help you much if your second shot stovepipes while trying to quick reload.
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Old October 18, 2009, 07:34 AM   #7
Jim Watson
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One of the gunzine writers calculates that the increase in velocity is 1/4 of the percentage increase in case capacity when going to an Improved chamber or just a larger case. Add 10% powder capacity, use it with the right powder, and get 2.5% more velocity. Thats 5-6 grains and 70-80 fps. Whee!

Most of the velocity increases claimed for Improved chambers is due to the lack of pressure tested load data and a tendency of shooters to load them up until there are clear overpressure signs, then back off half a grain.
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Old October 18, 2009, 07:58 AM   #8
ZeroJunk
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Jim, I can tell you for a fact that is BS.


280 AI 140 gr

58 gr won't disclose powder 2883
2871
2908
60 gr 3115
3115
3096
61 gr 3179
3201
3186
150 grain bullet

58 gr 2863
2875
2847
59 gr 3045
2976
2952
60 gr 3127
3115
3085
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Old October 18, 2009, 08:10 AM   #9
mapsjanhere
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Your table seems to have lost it's formating, what are those numbers?
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Old October 18, 2009, 08:36 AM   #10
Jim Watson
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Zero, read the second paragraph of my post. I would bet you are loading .280 AI to substantially higher chamber pressure than anything in the books for .280 Remington.

There was a fad a few years ago for building custom Mausers in .280 Rem because the gunsmith could put his time into making it look pretty instead of opening up the bolt face and magazine for 7mm RM. So the practicioners went to the trouble of reforming Winchester .270 cases to .280 because they were harder brass and would not show "pressure signs" as soon as the right headstamped stuff when overloaded.

As to your PM on powder choice, I had another guy tell me with a straight face that that product gave less recoil than anything else loaded to the same velocity.
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Old October 18, 2009, 09:05 AM   #11
ZeroJunk
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Quote:
would bet you are loading .280 AI to substantially higher chamber pressure than anything in the books for .280 Remington.
I'm sure that is the case. I can tell you that the difference in pressure and recoil between one grain when you get on the edge of maximum is quite noticeable.

I use the data in the manual now having lost the need for speed some time ago.


But, 5 or 6 grains to get 70 or 80 FPS must have been a challenge for the writer to find a powder that would do that and substantiate the point he was trying to make before he started the research.

Last edited by ZeroJunk; October 18, 2009 at 09:12 AM.
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Old October 18, 2009, 11:56 AM   #12
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The best cartridges to improve are ones with a lot of body taper like the .30-30 and .300 H&H. Improving a cartridge involves more than just changing the shoulder, you remove the taper as well. The 06 cartridge doesn't have much body taper so that is why you don't see much of an increase of performance.
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Old October 18, 2009, 12:25 PM   #13
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The 280 Rem was offered as a low pressure cartridge by Remington because of the old 760 Pump rifle it was offered in, didn't want a high pressure round causing extraction problems (the action was strong enough, but there wasn't a lot of camming action from the pump motion).

So a few years later Remington opted to introduce the 7mm Remington Express. The same as the 280 Rem but loaded for higher pressures that the Rem700 bolt action rifle could handle.

Not all reloading manuals differentiate between what is a "280 Rem" loading (especially since handloaders were hotrodding the 280 for their bolt rifles before Remington got it's marketing idea) and the 7mm Express.

If you are looking for some cool wildcats based on the 30-06, the Hawk family of cartridges has intrigued me for years. http://www.z-hat.com/HawkCartridges.htm

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Old October 18, 2009, 06:43 PM   #14
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The 30-06AI does shoot pretty good though....Here's a group that I fired the other day getting my 30'06AI Encore with a Eabco Barrel....
Shooting the 150gr Nolser BT at 3000fps...



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Old October 18, 2009, 07:01 PM   #15
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It seems that the .30-06 was not one of Ackley's biggest successes. Around 7% improvement in performance.

Probably the most advantage to be gained from AI treatment is case longevity.

The top performance gain seen from AI is the .25-35 WCF (no longer in production), the .30-40 Krag (also no longer in production, a shame since it equates to a rimmed .308 in performance with modern powders and AI treatment puts it in place to compete with the .30-06, also with modern progressive powder), the .250 Savage and the .30-30 Winchester. I have heard that the 6.5x55 Swede exceeds the .30-30 in a in performance gain with the 40 degree shoulder and (almost) straight-walled case. That would make it the fourth best performance improvement example of AI. 'Problem is, P.O. Ackley never experimented with it.

The .30-06 is way down the list of "successes" of the Ackley Improved cartridges with an improvement in velocity of somewhere around 7%. It was a sort of middle of the range improvement. Not bad but not great. Depending on the bullet weight and powder used, 7% improvement is a typical improvement from start to max for many .30-06 loads. I just looked in Nosler No. 3 and for a 168 gr Hollow Point Match Solid Base bullet over IMR 4895, the low end is 2460 fps and the high end is 2640 fps. That is a change of 7.3%. It doesn't prove anything. It is just one reloading manual that shows a velocity change from start load to max load (for that manual) that equates to the gain seen for the trouble to "AI" that cartridge.

The point is only seven or eight of Ackley's experiments showed performance (velocity) improvement at or over 10%, but they all showed vastly extended case life. It was not unusual to see these performance improvements with less powder or close to the same charge.
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Old October 18, 2009, 09:32 PM   #16
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From personal experience, the 30.06 AI is not really worth the effort. Minimal gains in velocity. My rifle is now rebarreled back to 30.06.
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