Reloading 280 AI

[Kurtdnelson]

I recently purchased a Kimber Hunter model in 280AI. Ibought Nosler brass and started development of a hunting load. Shooting went well until I reloaded the brass. I used Hornady dies, full length resized, measured each case for overall length and seated the bullets to the recommended overall length of 3.330. I then tried to chamber a round and I was unable to close the bolt. I checked every round and only 4 out of 20 would chamber.
I measured every case while looking for pressure signs. Every case was within all measurements listed in the latest Hornady manual. Anybody got an idea what the problem could be? I am leaving for a mule deer hunt soon and will use new brass, but I certainly want to resolve this issue when I return.
Thank you in advance for any help
Kurt

 

[Dmagna]

You didn't push the shoulder back enough

 

[Dmagna]

Also remember that Nosler loaded 280ai brass is different from their custom brass

 

[Dmagna]

Also have to make sure that you chamber is saami spec along with your dies. I have seen that with the 280ai. Someone used dies pre saami with a saami chamber and it didn't work

 

[Kurtdnelson]

Ok , what am I doing wrong? When I resize the shell holder is bottoming out on the die. Am I missing something?
Thank you

 

[xsn10s]

Ok , what am I doing wrong? When I resize the shell holder is bottoming out on the die. Am I missing something?
Thank you

Are the dies and shellholder made by the same manufacture?

 

[Kurtdnelson]

Yes, Hornady.

 

[lancetkenyon]

What's the difference between a die body and a pregnant woman? You can unscrew a die body....

Back it out of the press until you are only bumping the shoulder back .002-.003".

How much reloading have you done?
Do you have a headspace comparator and calipers to know when you are only bumping the shoulders back .002-.003"? Do you know what "bumping the shoulder back" means?

Just trying to find out what info you need to start the process.

If you are hitting the die with the shell holder, you are probably bumping the shoulders back way too far to start, so I doubt that the headspace is too long. I am betting it is the bullet seated too long. Or the case neck needs trimmed because OAL case length is too long. But I doubt that with the 40° shoulder and once fired brass.

Have you checked where the bullet is hitting the lands in your rifle?
What bullet?
What is your CBTO? Not COAL. (Cartridge Base To Ogive, not Cartridge Overall Length)
Again, do you have a comparator w. a .284/7mm insert and calipers to measure this length?

 

[lancetkenyon]

Are the dies and shellholder made by the same manufacture?

???
Does that matter? Never had an issue with using an RCBS or Redding shell holder in conjunction with an RCBS, Redding, Wilson, Hornady, Forster, or Whidden die set.

 

[Kurtdnelson]

I measured the case length, chamfered the mouth and seated the bullets to the exact same length as I did with the new brass.
I do not have a comparator, I have calipers.
I have been reloading for 20 years and I have never experienced this problem with any of the other guns I own.

 

[Plinker147]

It's either your case length is too long what do they measure? How much under max were they? Or are they at max length, that can cause this.

Shoulder not bumped back. Sounds like your over bumping tho.


Resizing die not set right.

Bullet hitting lands. Should still chamber but would be noticeably harder.

 

[Kurtdnelson]

Cases are at max length, only fired once.
Bullet not touching lands.
How does one make sure the die is set right?
I'm using 150gr. Nosler BT bullets

 

[Weatherby Fan]

I had the exact same problem with once fired brass that I had FL sized and trimmed to length and it still wouldn't chamber so my Gunsmith suggested this, I just turned my FL sizing die an 1/8 of a turn past where it bottomed out on the shell holder and it solved the issue.

At first I thought it was a OAL issue with the bullet loaded so I tried chambering my FL resized brass on its own and they wouldn't chamber either.

 

[lancetkenyon]

Make sure your die is an FL, not a neck sizer?
How old is the die set?
Since it is a factory rifle chambered in ..280AI, I would have to assume it is a SAAMI spec chamber. And if the Hornady dies are not custom, they should be SAAMI too.

What bullet? What COAL? Did you check with the bullet manufacturer's max COAL for that bullet? Different shaped bullets will have different max COAL. Even different lot numbers for the same bullet can vary on BTO measurement. What worked with one lot might not work with the next.

You state cases are at max length. Trim them .010" to minimum length. Then try again.