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  #1  
Old 11-16-2004, 06:29 PM
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7mm-08 Ackley Improved


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Does anyone know where I can get load data for an Improved 7mm-08
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  #2  
Old 11-17-2004, 06:39 AM
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For the 7mm-08 Improved, start with regular 7mm-08 loads listed in reputable loading manuals and work up from there. If the shoulder has been pushed further forward and your working with something like a 40-60 degree shoulder angle with absolute minimum body taper, then you can start with the middle listed load from most loading manuals....

D-A
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  #3  
Old 11-17-2004, 10:25 AM
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7mm-08 Ackley Improved

Thanks. The reason why I am looking at an improved versions is that I understand the "improved" case burns powder more efficiently and therefore improves accuracy. Apart from this can I expect much of an increase in velocity?
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  #4  
Old 11-17-2004, 10:46 AM
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Any improving of the .308 family of cases usually results in a 4% - 5% gain in velocity. It takes an equal amount of more powder to attain this.

The benefits of an "improved" case is less bolt thrust, better headspacing (on the sharper shoulder) and longer case life due to limited stretching after being fireformed.

There is a lot of talk about cases with straighter walls and sharper shoulders giving better combustion to the propellent charge. Can't prove it, but I tend to go along with the theory. Have several improved cartridges, along with a factory "short, fat" cartridge (7mm Dakota) and believe they all outperform the standard versions in propellent consumption.

As far as increased accuracy - that's a debatable issue.
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  #5  
Old 11-17-2004, 01:39 PM
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7mm-08 Ackley Improved

Thanks kdub - do you have a source of load info for this round. I have searched high and low on the net. Apart from some custom ammo makers I have come up with diddly scwat.
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  #6  
Old 11-17-2004, 06:53 PM
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Nope - don't have any firsthand info.

As stated previously, start out with published loads for the standard cartridge and slowly work up in 1/2 grain increments above recommended max loads until you either (a) hit the desired velocity/accuracy, (b) your good senses tell you to stop, (c) the brass exhibits high pressure load signs, or (d) the bolt lift/extraction is heavier than normal.

Each rifle and each chamber is going to be different with wildcat cartridges. There's no way to predict what will be max loads for your firearm, so best to start at a reasonable point with published data and very slowly work up from there.
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  #7  
Old 11-17-2004, 07:53 PM
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Chris,
Found some data for you, might want to approach this with caution as I can't find any indication that this cartridge was ever really created by Ackley....... so chamber dimensions may vary considerably.
Anyhow, this data compared to standard 7-08 should give you some idea of potential performance.
www.huntingnut.com
Gee, just found another, these loads are also from contributors and not tested in a pressure barrel, be careful!
www.loadyourown.com
Bryan

Last edited by Ab Rifleman; 11-17-2004 at 08:44 PM.
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  #8  
Old 11-18-2004, 08:45 AM
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7mm-08 Ackley Improved

Thanks Kdub and Ab, if you stumble across anymore load data please post it.

Many thanks.
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  #9  
Old 11-24-2004, 02:46 AM
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Quote:
Originally Posted by Chris R
Does anyone know where I can get load data for an Improved 7mm-08
Here is some load data for the 7mm IHMSA International cartridge used in unlimited silhouette pistols. It is a .308 necked to 7mm and fire formed. The shoulder is 38 degrees rather than the Ackley's 40 degrees, case length is 1.866". For all practical purposes it's the same cartridge. If anything, the Ackley will have a miniscule more case capacity, but don't try to load hotter as performance won't improve enough to warrant the higher pressure.

140 grain Nosler Solid Base;
Hodgdon H322 start 30.0 to 33.0 grains maximum. Groups ran .34" (32 grains) to .72" (31.0 grains) 10 shots - 100 yards in an Rem. XP Pistol! Velocity 2,196 fps to 2,412 fps (15" barrel).

Hodgdon 4895 start 28.0 grains to 32.0 grains maximum. Groups ran 1.10" (28 grains) to .64" (.32 grains). Velocity 1,963 to 2,240 fps.

168 grain Sierra MatchKing;
Hodgdon H322 start 29.0 grains to 32.0 maximum. Groups ran from .27" (30.0 grains) to 1.08 " (32.0 grains). Velocity 2,098 fps to 2,260 (again, in a 15" barrel).

Hodgdon H4895 start 30.0 grains to 33.0 grains maximum.


Other powders used are H-4198: 26.0 to 28.0 grains with 140 grain bullets. 26.0 to 29.0 grains with 154 grain bullets.

Winchester 748: 33.0 to 36.0 grains with 150 grain bullets.

Data is from Reloading Guide for Handgun Accuracy (IHMSA 1982) and Loaddata.com.

This cartridge is one of the most accurate ever designed, although part of that is the high quality of the arms built for it - ridgid single shot action Wichita and Remington XP pistols with precision fitted barrels and short lock time. I used Federal match brass with small primer pockets and benchrest primers, with H322 powder and my own 145 grain jacketed open point bullets. It would group .50" in a calm wind but always under .75" at 100 yards, and that with open sights and a 15" barrel! For deer sized game it can't be beat.

Good shooting.

axlenut

Last edited by axlenut; 11-24-2004 at 02:56 AM.
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  #10  
Old 12-08-2009, 06:07 PM
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Are you sure about that? My hornady manual lists the 7mm IHMSA's parent cartridge as being the 300 Savage.
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