280 AI questions

Sykes

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Joined
Feb 21, 2014
Messages
1,109
Location
Northern Co
I have a Cooper Timberline 280 AI coming anytime and need to get some dies and brass for it.
I typically use Redding master hunter dies for all my other rifles but am wanting to try the type s bushing die on this rifle. I emailed Cooper for their recommendation on bushing size but no response. The bushing die is new to me so I'm unsure what size to get and those little bushing aren't cheap. How does a guy go about selecting the right size bushing? I'm aware of how Redding says to find your size but is there a common for 280ai? Can you measure factory loaded ammo and order a bushing based off that mesurment?

About the brass has anybody used the hornady 280ai brass? Is it any good or should a guy just go with Nosler 280ai brass?

Any advice is appreciated!
 

The Oregonian

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Jul 20, 2012
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1,481
Location
Missoula, Montana
I am going with Nosler brass on the 280AI I have on order. Bushing size will depend on neck thickness, so various brass may be different. I bought Nosler factory 280AI ammo with 168 ABLR and got (going from memory here) about .312 diameter with loaded rounds. Take .02 off of that and you get .310. I also measured Nosler brass and got about .0135 neck thickness, which would put a loaded round at .311...so .002 off of that and you get .309 bushing size.

Don’t take my memory to the bank as I could be off by .002 or so, but those are the methods I use to get bushing size. Based on the above I would buy .309 and .310...I like to have more than one bushing - but you are right, those boogers ain’t cheap, especially if you get the nitride version.
 

J E Custom

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Joined
Jul 29, 2004
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10,723
Location
Texas
You need to measure a loaded case with the brand of brass/ammo you are going to use. (Different brands of brass have different neck thicknesses) then use the Redding recommendations.

J E CUSTOM
 

Sykes

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Joined
Feb 21, 2014
Messages
1,109
Location
Northern Co
Is the nitride bushing worth doing?

I'll probably use nosler brass. Bullet undecided. 162 eldx or maybe one of the Bergers if they will shoot out of it.
 

Cowboythunder

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Joined
May 27, 2018
Messages
64
Location
Greeley, Colo
Not to divert the conversation but if you change your mind, I have a brand new set of master hunter dies looking for a new home for a 280AI that I never received. They've never seen the press.

As for the bushings, neck thickness on the brass your using makes a difference in what size you go with. Several guys I know who use them keep a variety of sizes on hand to adjust for variances in brass thickness. Not very economical but, I guess I don't handload to save money...

One thing I would also take a look at is the Lee collet die. It sizes your case neck around a mandrel and produces excellent concentricity and in some cases it will uniform the neck wall thickness in my experience. The case neck thickness isn't critical since the mandrel sets the neck size from the inside. You can also buy an undersized mandrel for a nominal fee if you prefer to increase your neck tension.

I've used the Lee Collet die in conjunction with a Redding body die with very good results, but in all practicality have not seen enough of a difference in accuracy to abandon the master hunter dies.

I'm no expert or match shooter, I'm sure there are better ways out there...
 

johnmyers

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LRH Team Member
Joined
Oct 12, 2009
Messages
106
Measure loaded round neck diameter them get bushing .002 to .003 smaller than loaded round. Probably .003 for a hunting rifle or you could get both and see which one shoots best.
 

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