270 Dakota

[davkrat]

Anybody know anything about this round? 270 Dakota It seems like it would slightly surpass a 270 Weatherby without a belt. How does this compare to the 270AM and 277AM? I know the 270AM is a 7mm RUM necked down but what is a 270AM?

 

[Ernie]

I shoot a 7mm Dakota in a center-grip XP-100 specialty handgun. It is basically a ballistic twin to the 7 STW.
The Dakota is a smaller capacity than Kirby's wildcats. I do use the 200 grain WIldcat bullet with 76.0 grains of Retumbo moving at 2706 fps from my XP (Smidget under a 18" barrel).

 

[sewwhat89]

Like was mentioned, a 270 AM is a 7RUM necked down. A 277 AM is a 338LM improved and necked down to .277. I think Kirby has his own version of the 270 Dakota improved to his AMish dimensions called a 270 AXM (Allen Xpress Mag) iirc.

That is the one like the 270 Dakota, and it has peaked my interest too; however, price and consitency of the brass has slowed me from looking into that round. Lapua was rumored to be taking over manufacture of the Dakota brass. If they do, it will still be expensive, but more likely worth the added cost to get such quality brass. On another note, it would allow you to push the charges a little higher and maintain the integrity of the brass if Lapua made it.

 

[coupalr]

What about shortening 300 rum brass to make Dakota brass? I have been thinking of building a 300 Dakota out of a barrel chambered in 300win mag that has a chamber problem and I figure the Dakota would be the way to go since I would not lose any barrel length like I would if I rechamber in 300 win mag. I just don't like the price of the dakota brass or the possiblity of losing a supplier.

 

[davkrat]

According to the Nosler guide the RUM case has a .534 cas head while the Dakota has a .545. The level of performance I am looking for is to launch a 150-160gr bullet around 3100fps. I know the 270 Weatherby will do this. I assume a 270-300 Win Mag would do this but I don't really want a belted magnum. JD338 says he gets around this level of performance from his 280 Ackely so I may just be able to get the same from a 270 Ackley. I really want a walking rifle with abround a 24" barrel. I assume that to get the performance out of the big Allen Mags you need a pretty substantial rifle with a long barrel. That's not what I am looking for at this time. I'm looking for more of a 500-600 yard gun for up to the occasional Elk but mostly hogs and deer.

 

[Geezer]

You might look at the 270WSM. The Nosler book shows 130gr loads to 3307fps, 140gr to 3186, 150gr to 3007 and 160gr to 2975 from a 24" barrel. Not quite the speed you're looking for, but pretty close for a standard cartridge.

 

[davkrat]

I have a long action that I am planning on rebarreling. I just don't like short action rounds in a long action. My brother has a .308 built on a long action and there seems to be so much extra room in the magazine. Probably just an aesthetic thing. I've been emailing Kirby but he is taking off to hunt for a while. His Xpress might be in the right range. I don't know if the dimensions of the Dakota case would be an issue in a magazine designed for a standard '06 size case. If I can get 3100fps with a 155gr out of 24" barrel and a 270 Ackley I may just go that route. It seems like JD338 is getting that out of his 280AI.

 

[sewwhat89]

From what you have stated now, I would go with a 280 AI hands down. You can get 160 gr bullets to 2950-3000 fps with a 24" barrel. Nosler is making 280 AI brass now. That would also be an advantage as you do not have to do any fire-forming. If you wanted to drop back to 150 NBTs for use on hogs and such, you should be able to get a hair under 3100 fps. Hornady makes their Interbond in a 154 gr bullet, and if that shoots well for you . . . . They also make a 154 gr SST and 162 gr AMAX. You could just buy a bunch of Hornady bullets, but I have heard some folks express concern over air pockets in the Interbonds. If that was a concern of yours, stay with the 150 gr NBTs and 160 gr NABs. Of course you can always play with the heavy SMKs or Bergers when you wanted to really strech things out.

I know it is kind of an forgotten round, but a 7 BooBoo would fit the bill. It has the capacity of the 300WM without a belt; however, you are stuck with RWS brass which is as pricey or worse than the Dakota but top-notch.

 

[coupalr]

Davkrat, I thought the case head on the Dakota was larger but Barney Lawton said that he had them both in his hand and he said they were the same size. So I guess I will have to look into it further.

 

[davkrat]

Does anyone have any info on a 270 Gibbs? From what I have been able to gather the GIbbs are slightly more improved than a Ackley. The shoulder is bumped forward shortening the neck. I have found info on the 30 gibbs but nothing on the 270 gibbs. Apparently the 30 Gibbs holds 7 more grains of IMR4350 than the .30-06. Using the figures in the Nosler Manual the 270 Win holds 64gr. (100%) and the 270 WBY holds 82gr. (100%) A 7 gr. increase over the 270 64gr would be 71gr which is a little less than halfway between the two. Where would the 270 AI fall?

As far as Nosler producing 280 AI brass now, can't that same brass be necked down to a 270 AI? Is the shoulder location different between the two? I know that the parent cases are 1.948 to shoulder in 270 and 1.999 in 280 but where do they land in the Ackley versions? I can't seem to find a drawing of the 270 AI. Thanks

 

[sewwhat89]

Go to stevespages.com to check out a chamber drawing for the 270 Gibbs and AI versions. That will give you an idea of the difference. My old barber's shooting partner shoots a 270 Gibbs with a 27 or 28" barrel. He is getting 3500 fps with 130s and 3200 fps with 150s. Keep in mind these are claimed not witnessed velocities so take them with a grain of salt. I have thought about doing the Gibbs again because of the 280 AI Nosler brass. I thought that would fire-form a little better than standard 270 WW brass would. The downside to the Gibbs round is the short neck; however, if this is a hunting rifle that is probably not an issue. Keep us informed. . . .

 

[davkrat]

Steves Pages doesn't have the Ackley in 270 only the Gibbs. Why is having a short neck bad but acceptable in a hunting rifle?

 

[sewwhat89]

The long neck allows you to chase the lands as you shoot out the barrel. If it is a hunting rifle, you will not be shooting out the barrel anytime soon.