Cooper 280AI Loads Advice

tyewabell

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Dec 19, 2014
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I've got a cooper excalibur 280AI that I'm about to start reloading for and was looking for advice on a starting point in regards to powder charge, COAL and anything else you might have advice on. The plan is to shoot 140 gr. Nosler Accubonds out of the gun, and I prefer a non temperature sensitive powder.

This gun shoots great with the right load. Best groups so far have been under .25MOA at 200 yards with Federal Premium 140 grain ballistic tips in 280 rem that I've been fire forming. I've also shot Nosler Custom 280 AI 140 grain accubonds out of it but they are generally in the .75 MOA range fwiw.
 

PGJPJ

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May 29, 2015
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Oregon
Nolser lists IMR 4831 as the most accurate with the 140 grn bullets. I'm always surprised, given the variability in rifles builds (throat, barrel tolerances, ect) but Nolser book loads have often worked out very well for me.

If you aren't too concerned with speed, you might look at H4831sc for it's temperature stability.

You may also want to consider going heavier on bullets. Some of the 168's have incredible BC, and at longer ranges will have a clear advantage over the 140's. Maybe with RL26 or something of that nature.

Just depends on what your trying to do with your rig. :cool:
 

BEEMAN

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Oct 20, 2011
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I agree with PGJPJ. Go with a 168 gr. I use H4831SC with a 168 Berger classic hunter in my Cooper. It is very accurate. Not all that fast at 2880 fps but it works good.
 

tyewabell

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Dec 19, 2014
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Thanks for all the info. So going by Nosler's load data, I'm shooting for a COAL of 3.33 with a max powder charge of 60 grains of IMR 4831 for a 140 grain or 59 grains of H4831SC with the same COAL for a 160 grain.

Cooper's stated load for the 280AI's they build is apparently the same for each gun. COAL of 3.32 with 56 grains of RL19 and a 130gr SGK. Interesting to see the .01 difference in COAL between Nosler and Cooper.

Is there much of a difference between the various 4831 powders in terms of temp sensitivity?

Also, I don't plan to shoot over 600 yards with this gun just yet, longest range I have access to is 500 yards as it is, so the heavier bullets aren't needed at this time with Mule Deer and Whitetail as the targets for the time being. Fall of 2016 when I'm chasing Elk, I'll develop a load with either 160's or 168's.
 

BEEMAN

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With my Cooper I am at 3.225" COAL. This is with a 168 Classic hunter. Using 58.5 gr of H4831SC. I was quite disappointed that I could not even load to mag length. I would of been WAY into the lands. Not sure why Cooper would chamber them like this.
 

tyewabell

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Dec 19, 2014
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Shot some loads this morning to see what my Cooper likes best. The loads followed Noslers recommendations for the 140 grain Accubond with IMR 4831 at powder charges of 60, 58 and 56. The best group for my gun was with the 58 grain load and it shot around .33" at 100 yards. Second best was the 56 grain load at around .5" at 100 yards and the worst by far was the 60 grain load which was about an inch at 100.
 

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CKTROTH

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Aug 9, 2015
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I have been shooting Speer 145's and 54.5 Grains of IMR4350 in my 280 AI. I tried the Nosler Brass and found the factory 280 Remingtons do alot better in my Rifle also. Mines a Mauser action with a 26 inch Lilja Bull Barrel with a Timney trigger.
 

BigSwede

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Aug 2, 2014
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If your choice is the 140 accubond then I'd start at the nosler length 3.33 and run a ladder with H4350 or the new enduron 4451. Otherwise your load you have with the 4831 may be the ticket. Play with depth a bit. good luck!

-Swede
 

tyewabell

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Dec 19, 2014
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40
If your choice is the 140 accubond then I'd start at the nosler length 3.33 and run a ladder with H4350 or the new enduron 4451. Otherwise your load you have with the 4831 may be the ticket. Play with depth a bit. good luck!

-Swede

Thanks for the advice. I'm going with the current load for now, too close to season and not enough time left to tinker as of right now. This coming spring I'll be playing with several different variables though.
 

azjim

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Aug 11, 2014
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Bringing this thread back to life.
Recently purchased a Cooper model 52 in 280AI.
Anyone willing to share recent load data/results ?

Thanks Jim
 
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