Cooper 280ai reload issues

[Weatherby Fan]

Try the factory Nosler 140gr Accubond ammo, I've built 9 different 280AI rifles and all but one shot the 140gr AB very well,
Most of my rifles do not like the 162gr ELDX for some reason ?
My latest one has a 24" #2 contour Benchmark 1-8.5 twist so I'm hoping it will shoot the 162gr ELDX bullets and or the Hornady Factory ammo,

I've had good hand load success with R22, R26,

 

[26Reload]

I loaded some old version nosler with tan tipped 150gr....shot really good..but no more of those bullets...tried 168gr...okay shooting but really slow in my 22" noodle barrel before hitting pressures.....will eventually head back dow to 140gr....just seems like a better performance out of the 280ai cartridge....

 

[Doninidaho]

I have a custom Rem 700 in .280AI that I can get serious accuracy from almost any bullet I've tried. However, I have the Kimber Mountain Ascent in .280AI that I can't get less than 1MOA with any combination. Sometimes you just get a *** and my experience has been that's fairly often with those high end factory pseudo customs.

 

[lancetkenyon]

Try a match LR primer. CCI BR2 or FED GM210M
RL23 is awesome in mine.
Try a 175 Berger Elite Hunter, 168 Berger Classic Hunter, or 165 Sierra SGK Gamechanger. Much more forgiving bullets than a VLD or ELD-X in my findings.

 

[RockyMtnMT]

What twist is in the Cooper? My memory is they are slow. Not sure though.

As stated earlier in the thread, our 143g Hammer Hunter at near 3200 fps is tough to beat out to pretty long range. If the rifle has any desire to shoot well it should be found with the Hammer Bullets. If you can't get our bullet to shoot well we'll refund your money.

 

[Sykes]

Coopers are a 9 twist in the 7mms

 

[lancetkenyon]

What twist is in the Cooper? My memory is they are slow. Not sure though.

As stated earlier in the thread, our 143g Hammer Hunter at near 3200 fps is tough to beat out to pretty long range. If the rifle has any desire to shoot well it should be found with the Hammer Bullets. If you can't get our bullet to shoot well we'll refund your money.

I bet you have never had to back up that guarantee.
Yeah, the Hammer Hunters shoot very well.

 

[RockyMtnMT]

Coopers are a 9 twist in the 7mms

That's good! Maybe it is Kimber I was thinking of. One of these higher end production rifles are 9.5". Then there is the occasional 10" 7mm.

 

[Tex LR]

Purchased Cooper 52 Excalibur in 280 ai and am struggling to find the right reload for it. Here's what I've done thus far:
4831sc with 162 Eldx, charges from 56.5 to 59.5. Adjusted seating depths and can get decent groups but not sub Moa as it is supposed to shoot. Accuracy just not there and ES minimum was 39. Also tried 168 vid's with pretty similar outcome.

H1000 w different bullets as well. 162 Eldx, 160 NP, 168 vid. Nothing to be excited about.
Keep reading how Rl 26 may be the ticket but I can't find any. Looking for advice and any help is greatly appreciated.

My 52 Jackson in 280AI likes 56G of RL22, FED210M, Nosler Brass and Berger 168VLD's. Very tiny groups.
My 52 Excalibur in 280AI likes 52G of IMR4350, FED210M, Nosler Brass and Barnes 145 LRX. One holer.
The newer Coopers in 280AI are 1 in 9 twist. The older ones were 1 in 10. Good luck.

 

[RockyMtnMT]

I bet you have never had to back up that guarantee.
Yeah, the Hammer Hunters shoot very well.

We have swapped out a few boxes for guys that didn't notice the min twist recommendations. In three years we have not needed to refund money.

 

[RockyMtnMT]

My 52 Jackson in 280AI likes 56G of RL22, FED210M, Nosler Brass and Berger 168VLD's. Very tiny groups.
My 52 Excalibur in 280AI likes 52G of IMR4350, FED210M, Nosler Brass and Barnes 145 LRX. One holer.
The newer Coopers in 280AI are 1 in 9 twist. The older ones were 1 in 10. Good luck.

This must be What was stuck in my head thinking Coopers were slow twist.

OP may want to manually check his barrel twist.

 

[Tex LR]

This must be What was stuck in my head thinking Coopers were slow twist.

OP may want to manually check his barrel twist.

My examples as follows:
Serial# 10XXX is 1 in 10
Serial#31XXX is 1 in 9

I remember them changing it. I don't recall exact timing however. It was probably 7 to 10 years ago. Worth checking if trying to shoot the heavier stuff.

 

[Northriver]

Thanks for all the input guys. The barrel is 9 twist. As recommended, I have changed primers and bullets. I am seeing better results with 150 eld's and have shot these with both 4831SC and RL 22. ES is now coming down to single digit which is what I was after. Going to continue to play with depth but anything will be seated pretty deep to be able to use mag.

Anyone know what is the deal with RL 26? I cannot find it anywhere.

 

[blkdog]

My Cooper loves the Nosler 168 Accubond Long Range with 58.5 grains of RE19 a Federal 210M and .o2o off the lands .42 at 100 for five shots avg velocity 2950 with SD 11.4 and ES of 29