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270 Allan Magnum?

 
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  #8  
Old 10-20-2005, 04:17 AM
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Re: 270 Allan Magnum?

Kirby,
you are saying you do recommend using the 300 RUM cases correct? Just to make sure 100%.
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  #9  
Old 10-20-2005, 03:04 PM
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Re: 270 Allan Magnum?

Yote Killer, I would highly recommend you get this 270 AM if you want a true long range hammer,

If you do get it don't fart around with any bullet other than the 169.5 ULD. I am sure all the other bullets work great but trust me, this bullet/ rifle combo is on another planet.
I have shot 3" groups at 800yds with fireforming loads and I managed to land 2 shots within inches of eachother at just shy of 1700yds with the full tilt loads.
I am in no way trying to bad mouth this round with bullets other than wildcats, I am sure it does great. But with these ULD bullets it is just above and beyond anything else.
Hopefully in a month I will be posting some pics of what it does to a whitetail but we will have to wait a while.
As for loading i used the 7rum brass and necked down 3/4 of the way to leave a good crush fit. We used 97gr of WC-872 powder for the fireforming, this gave about 3250-3300 fps which is a lot of thump for something on the other end of the bullet. Just check out our post about pdog shooting and BJ shooting the cow.
I settled on 104gr of WC 872 for the full bore loads and I actually haven't chronod them yet but I am sure it is around 3450.

It is a hell of a round and Kirby builds a hell of a rifle so I am sure you wouldn't be dissapointed if you get one.

Take it easy
Steve
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  #10  
Old 10-20-2005, 04:57 PM
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Re: 270 Allan Magnum?

I second what Lerch said. This is a great cartidge. I used the 140 grain accubonds for a brief amount of time to take a Mountain Goat as Kirby pointed out. I plan to switch to the 169.5 ULD's this winter. Then hopefully I can take a deer, elk, and maybe a cow moose with that combo.
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  #11  
Old 10-20-2005, 06:22 PM
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Re: 270 Allan Magnum?

270WSM,

Simply put, its a 7mm Allen Mag necked down to 270. Based on the Lapua and designed to be used with the new to be released 185 gr ULD RBBT.

More to come on this little jem soon!!

Kirby Allen
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Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

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  #12  
Old 10-20-2005, 07:45 PM
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Re: 270 Allan Magnum?

50,
someone asked and i would also like you to clarify regarding the headspacing on 300 brass compared to 7mm. i thought about trying some federal 300um brass sized for my 7um.is it a bit longer or is any 300 brass a bit longer than the 7 ?
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  #13  
Old 10-20-2005, 11:11 PM
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Re: 270 Allan Magnum?

Dave,

On paper, the 7mm, 300, and 375 RUM all have the exact same headspace measurement. Meaning the only difference dimensionally between the three is the neck diameter and the resulting neck length.

That said, what is printed on paper and what makes it out the door from Rem are at times two different things unfortunately.

I recently encountered a batch of 7mm RUM cases that were roughly 0.010" shorter from the rim to the shoulder/neck junction then any others I have used in the 270 Allen Mag.

As there is only a 0.007" deduction in the 7mm RUMs neck diameter to that of the 270-7mm RUM(fireforming load), this is not enough to produce a positive shoulder to gas seal off from. Even if you only size the first 2/3 of the case neck this is not enough to limit case stretching.

The problem is that I generally use match grade striker assemblies in my Allen Magnums and with the heavier striker spring, when the striker impacts the primer, it will drive the case forward in the chamber until it is physically stopped by the case shoulder. Normally, the 0.004" crush fit built into these chambers totally eliminates this problem but when the parent case has its shoulder set back 0.010" farther to start with you can not control this.

The resulting fireformed brass will have a slight thinning just ahead of the case head, the start of case head seperation.

Now if you only neck size or partial FL size this is not a real concern but it is an issue that is easily corrected by using 300 RUM brass instead of the 7mm RUM at least this was my thinking so I tested it out.

Everything seemed to work fine, even case neck thickness was not a problem, in fact it tightened the chamber to neck fit up by a couple ten thou while still allowing enough room for safe bullet release on firing.

Best of all, no matter where the factory shoulder is located, using 300 RUM brass, when you neck the case down to 270 you can position that neck where ever you want to offer a positive gas seal which will eliminate case head stretching.

I do recommend that you make sure the neck diameter is such that will work safely in the rifle though before heading to full tilt loads.

The 300 RUM from federal should work fine in your 7mm RUM. Just check for case length after sizing and neck diameters as well. You may need to turn your necks slightly but I doubt it. Still, check before you start shooting.

Kirby Allen(50)
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Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

allenmagnum@gmail.com
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