280 AI (again)

[rharfo]

Ok folks, I recently posted a thread that ended up with a dozen pages on the difference between the saami spec and Akley 40 degree specs of the 280 AI. Heres the new issue I am having. I bought a brand new Dakota 97 Hunter in 280 AI. Fireformed some casings. After full length resizing they will hardly go back into the chamber. During close inspection it is obvious to the naked eye that there is a difference in the fire case shoulder and the resized case. From my previous post I made it known that I confirmed with Dakota that my gun is a 40 degree pre sammi chamber. My dies are over 10 years old confirming from Redding info that they are the orginal spec 40 degree. I have emailed Dakota but its a holiday weekend. So, what is the issue. Why is the fire formed case not "fireformed"!? Is there a headspace issue? Should I buy a neck sizer die? Is the chamber not cut complete? Not sure it will show up in the pics but the case on the right is the fireformed vs the left being full length resized. You may be able to see that the fire formed is "rounded" and the resized has a sharp shoulder. Been reloading for over 10 years. I had a factory REm 700 280 rechambered to ackley with NO issues. The Dakota was VERY expensive and to have ANY issue is less then acceptable! Thanks in advance for your thoughts.

 

[FEENIX]

Sorry but you might consider posting pictures, I definitely cannot tell from the quality of the pictures. Perhaps my eyes are worst than I thought.

 

[freebird63]

I would say try a neck sizer die. I have two sets of dies for my 280AI. A set of Lee full length dies and a Redding comp seater and neck sizer die. A neck sizer die is not expensive. Its worth a shot. But I have heard once you neck size a case from a certain gun that you can only use the case in that gun again unless you full length resize it. But have never tried it myself. Keep us posted

 

[Daveinjax]

Neck sizing only will get you past your problem and the Dakota should shoot fine but the rounded weatherby looking shoulder is odd. I have heard there are several different 40º Ackley dimensions out there and some may have a rounded shoulder. A full charge fire form casing should be fully formed so I think there is something wrong with the chamber or it's different 280 AI variation.
I was thinking about this and it occurred to me that Dakota is part of Freedom Group. Thats the same people who have destroyed Remington and Marlin. My guess is you have a defective chamber. Hopefully since you paid so much for it they will take care of it but it's Freedom Group so they may declare it within specifications and stick you with it.

 

[TOM H]

rharfo, this is copy of Dakota 2012 price list

Dakota Arms Price List 2012

As you see no listing for a 280AI but the do custom chambering at extra cost.

That rifle may of not been ordered as SAAMI spec 280AI or build as one. I know Gulf Breeze handles some of their custom chambering and sure they were order that way by them.

you need to find out what chamber you have and go from there.

 

[yawn]

When you say that it hardly fits in the chamber do you mean its tight to slide in or its ok but the bolt is hard to close? and do the fire formed cases fit in the chamber before they are resized?

 

[rharfo]

Dakota confirmed that the chamber is the 40 degree Ackley not the Nosler SAMMI spec.
280 Rem ammo slides in smooth and bolt closes very easy. The fire formed pre resized cases work like butter in and out of the chamber.
Resized case causes the bolt to open/close very stiff.

One of the members said it best "looks like a Weatherby rounded shoulder".

I think Dakota needs to recut the chamber.

So much for being able to "share" ammo with my kids Red Hawk Rifle 280 AI that is currently being built.

And I am just gonna put this out there, the gun was sticker priced at 4495. The dealer was doing a 20% sale so I bought it for 3600. This gun should load, fire and clean itself! And I am selling three of my other guns to pay off the CC bill.....just my luck...

 

[woods]

rharfo sorry you are disappointed and you are right, Dakota should recut the chamber after setting the barrel back the number of threads needed to clear it for the new chamber. Perhaps even get the SAAMI version this time as it will make life simpler in the future.

As far as "sharing" ammo with another gun, I have yet to see that work between 2 rifles. Sure the fire formed ammo from one will fit in the other but then the fire formed ammo from the other won't fit in the first. The chambers would have to be virtually identical down to within thousanths of an inch in all dimensions.

You could get a Lee Collet neck sizer in the 280 Remington caliber and it would resize your fire formed ammo so you could use the rifle as is if Dakota doesn't make it right

Let us know how it turns out

 

[blipelt]

Sorry but I am a little confused. I just got my 280AI from Cooper firearms. It is chambered in the original AI chambering supposedly from what they tell me. I got a 40degree RCBS dieset that was rec. by them. I bought Nosler custom brass also. Everyone is saying Nosler is sammi spec. But the brass chambers in my Cooper without any resistance from the factory? Is the sammi spec longer or shorter, I thought it was longer? I plan on creating a false shoulder and fireforming the brass much like I do with my Dasher. If I find any discrepencies with the brass.

 

[woods]

Sorry but I am a little confused. I just got my 280AI from Cooper firearms. It is chambered in the original AI chambering supposedly from what they tell me. I got a 40degree RCBS dieset that was rec. by them. I bought Nosler custom brass also. Everyone is saying Nosler is sammi spec. But the brass chambers in my Cooper without any resistance from the factory? Is the sammi spec longer or shorter, I thought it was longer? I plan on creating a false shoulder and fireforming the brass much like I do with my Dasher. If I find any discrepencies with the brass.

The SAAMI spec is SHORTER so there is the possibility that it will have too much headspace in your older chamber and flatten your primers like it did on mine

 

[blipelt]

Thanks for the info. Makes more sense now.

 

[yawn]

Dakota confirmed that the chamber is the 40 degree Ackley not the Nosler SAMMI spec.
280 Rem ammo slides in smooth and bolt closes very easy. The fire formed pre resized cases work like butter in and out of the chamber.
Resized case causes the bolt to open/close very stiff.

One of the members said it best "looks like a Weatherby rounded shoulder".

I think Dakota needs to recut the chamber.

So much for being able to "share" ammo with my kids Red Hawk Rifle 280 AI that is currently being built.

And I am just gonna put this out there, the gun was sticker priced at 4495. The dealer was doing a 20% sale so I bought it for 3600. This gun should load, fire and clean itself! And I am selling three of my other guns to pay off the CC bill.....just my luck...

Putting aside the possible difference in the chambers the chambering problem sounds like a simple head space issue. I would try turning the sizing die down in small increments and see if bumping the shoulder back a little makes a difference. As to the slightly rounded shoulders could they be just a little underformed? ie not quite enough pressure to blow them out nice and sharp during the fire forming process?

 

[yawn]

Sorry but I am a little confused. I just got my 280AI from Cooper firearms. It is chambered in the original AI chambering supposedly from what they tell me. I got a 40degree RCBS dieset that was rec. by them. I bought Nosler custom brass also. Everyone is saying Nosler is sammi spec. But the brass chambers in my Cooper without any resistance from the factory? Is the sammi spec longer or shorter, I thought it was longer? I plan on creating a false shoulder and fireforming the brass much like I do with my Dasher. If I find any discrepencies with the brass.

This has been discussed a bit lately but the only physical evidence I can find is Woods flattened primers. Iv been using nosler brass in a cooper chamber 280ai for years with no problems at all( zero stretch in case length).
The opposing theory to to different chamber lengths is that the chambers are the same but the datum at which they are measured is different.
To answer the question for myself I have some original ackley go gauges and new nosler brass coming. I plan to check the chamber, the new brass dimensions and then the fully fire formed dimensions.

 

[blipelt]

Yawn I did a little tinkering now that my cooper NEW 280ai is back from the factory. They put a little blurp at the bottom of the repair saying "Cooper Firearms 280AI chambers are not SAAMI spec. They are chambered to the original P. O. Ackley spec. SAAMI spec ammunition may not work in a Cooper Firearm. In my explanation I put I had New Nosler Brass that wasn't ejecting and the rifle hasn't been fired.

Tinkering I did.

I took the firing pin assembly out of my bolt and put a new Nosler brass in and chambered it. I checked for any movement in the bolt when the brass was chambered. There was none! I removed the brass and checked you had movement! I am going to try the brass out. I might seat the bullets into the lands with a light load to see how it does. Don't want to end up ruining a bunch of brass. Having movement when fireforming brass makes really poor quality brass.

Brent