280 Ackley vs 7mm Rem.

[Unoboats]

Had a 280 built on a 700 action with # 4 contour bbl and titanium firing pin Kevlar stock. Weighed 7.2 lbs. scope will take some research but this gun shoots sub bore groups most of the time when I'm on my game.

 

[captacademy]

Thanks for the advice 41mag.

 

[Clark]

Having loaded and shot both a lot.
Pressure for pressure, the AI won't get within 200 fps of the 7 rem mag.

Comparing cartridge performance with Quickload and Quicktarget at close to optimum powder choice and 65kpsi the two get within 110 fps.
The problem is that the max practical usage of the 280AI will be ~ 67kpsi and the max practical for the 7mmRM will be ~ 71 kpsi. This is because the 7mmRM case head is stronger.
I would imagine that using loads based on real work ups that the 280AI at 67kpsi would be ~ 200 fps slower than the 7mmRM at 71kpsi.
That 200 fps represents 100 yards for velocity.

7mmT/CU ............. ...........26.1 gr H335 2330 fps -471 yards
7-30 Waters ........................30 gr W748 2456 fps -395 yards
7mmBR ..................... ......31.2 gr W748 2510 fps -360 yards
7mm IHMSA ........... ............40.2 gr Re17 2704 fps -247 yards
7mm-08 ............... ........40.6 gr IMR4895 2789 fps -198 yards
7mm-08AckleyImproved ..... ....43.6 gr Re15 2833 fps -171 yards
7x57mm ...........................44.6 gr Re15 2843 fps -165 yards
7x57mmAckleyImproved ... ......46.4 gr Re15 2873 fps -150 yards
284Win ........................50.0 gr IMR4350 2890 fps -172 yards
280Rem ...........................53.5 gr H414 2961 fps -152 yards
7mm Rem short action ultra mag 55.5 gr Re17 3015 fps -73 yards
280RemAckleyImproved ....... .57 gr IMR4350 3019 fps -71 yards
7mmRemMag .................... ..68.2 gr Re22 3129 fps -15 yards
7mmRem ultra mag ........ ....83.3 gr IMR7828 3130 fps -15 yards
7mmWeathMag ............. .......71.8 gr Re22 3170 fps +7 yards
7mmSTW ........... ..82.2 gr Ramshot Magnum 3158 fps 0 yards

 

[Pdvdh]

Both of my 280 AIs deliver ~150-175 fps less MV than my 7mm RMs with handloads worked up to maximum operating pressures in all rifles.

 

[Shootin4fun]

I have been searching for a smith to do my work on my rifle, in my searching i came across what it looks like a good deal, Cooper makes a couple of 280 ackley rifles, one I believe a stainless rifle, set in a B & C Medalist stock, bedded for around MSRP $1600 or so, they also guarantee a 1/2 inch group @ 100yrds. sounds like a pretty good deal, I'll just have to see how long a waiting there is for the rifle.

Also has anyone had much experience with Cooper rifles, they look like nice guns for the money.

I have been thinkng about something a little lighter in recoil with similar ballistics to ny 7mm RM which has brought me to the 280AI. I've seen the Coopers at a store near me but didn't realize they were that close to the 7RM. They are on display with 100 yard 3 round targets and the loads that produced them. Most are cloverleaves. Really nice wood stocks, good looking guns.

Never heard anything about the Cooper - O connection but not too concerned about it now because of the dissociation of him and the company that bears his name.

 

[Clark]

So I would never know the difference between 280AI and 7mmRM when shooting.

But I have had enough forming Ackley cases. I am trying to kick the habit. Just say no to Ackley reamers. With each new barrel, make a chamber that fits the brass.

 

[The Oregonian]

I think the Cooper targets are around 40 yards, not 100. I have never owned or shot one, but that said it seems like most are shooters based on feedback here.

 

[FEENIX]

Zombied!

 

[Shootin4fun]

I think the Cooper targets are around 40 yards, not 100. I have never owned or shot one, but that said it seems like most are shooters based on feedback here.

The targets do have "100 yards" written on them with the name of the shooter/tester and the load. I assume they are are mounted in a vice of some sort.