280ai vs 7rem mag.... can someone explain this?

Kurt505 · #1 12-10-2017, 11:49 AM

After reading Dick's comment on the 270wsm thread about the 7rem mag I started doing a little data research. Being that I already have a few 280's I'm fairly familiar with their performance, and wanting to see what a 7rem mag could do with premium ammo I looked to Nosler Trophy grade ammo for specs.

To be honest I was expecting about 150fps between the two, but to my surprise at 140gr the 7rem only had 50fps over the 280ai, but what was most surprising was at 160gr the 280ai was listed at, get this, 25fps FASTER than the 7rem!

I chrono' the 140 accubonds in my rifle and they are pretty much bang on, I've also verified the load with my scope out to 800yds. I don't have a 7rem mag to test but I'd like to know if anyone has tested either one of these loads in the 7rem, or can explain this?

elkhunter11 · #2 12-10-2017, 11:59 AM

Quote:

Originally Posted by Kurt505

After reading Dick's comment on the 270wsm thread about the 7rem mag I started doing a little data research. Being that I already have a few 280's I'm fairly familiar with their performance, and wanting to see what a 7rem mag could do with premium ammo I looked to Nosler Trophy grade ammo for specs.

To be honest I was expecting about 150fps between the two, but to my surprise at 140gr the 7rem only had 50fps over the 280ai, but what was most surprising was at 160gr the 280ai was listed at, get this, 25fps FASTER than the 7rem!

I chrono' the 140 accubonds in my rifle and they are pretty much bang on, I've also verified the load with my scope out to 800yds. I don't have a 7rem mag to test but I'd like to know if anyone has tested either one of these loads in the 7rem, or can explain this?

It would appear that they are loading the 280AI to a higher pressure, or they are using a powder for the 7mmremmag, that doesn't produce the velocity that the cartridge is capable of.

Kurt505 · #3 12-10-2017, 12:04 PM

Quote:

Originally Posted by elkhunter11

It would appear that they are loading the 280AI to a higher pressure, or they are using a powder for the 7mmremmag, that doesn't produce the velocity that the cartridge is capable of.

That would make sense, maybe for accuracy reasons? Could be that the accuracy node would be around 2950fps and that's as close to that speed they could get with either round?

jayquiver · #4 12-10-2017, 12:12 PM

I believe that data is from their factory ammunition.

I know for their Load Data results they use a 24" barrel for the 7mm Rem Mag and a 26" barrel for the 280ai. Perhaps they use the same length same length barrels, respectively, when testing their ammunition. But I don't know how much more velocity you get from 2" more of barrel? Perhaps thats why there is a difference.

All I know is that if I didn't own a 7mm Rem Mag I would own a 280 or 280ai.

CaberTosser · #5 12-10-2017, 12:19 PM

Just as some cartridges can be purchased that run a higher velocity than standard for the chambering, some will be loaded to about normal. That 7mm Rem Mag could be loaded to a higher velocity. Note that the links you provided were comparing Accubonds in the 7mm Mag to Partitions in the .280 AI. The profiles of the bullets will create velocity differences as they will have longer or shorter bearing surface to the barrels rifling and different pressure curves will result.

Hornady loads their 162 grain .280 Ackley ELD-X to 2850 FPS yet the same bullet in the same Precision Hunter ammo line in 7mm Rem Mag is 2940 FPS. Their 7mm Rem Mag 162 SST in the Superformance line is rated to 3030 FPS. All are noted as being from 24" test barrels.

I have a stockpile of Hornady's discontinued Light Magnum line in both 165 grain SST and 165 grain Interbond variations and its rated to 3015 FPS. That line was replaced by their Superformance line up and in some cases the newer Superformance achieves lower velocities such as with the Superformance .30-06 165 Interbond which is rated to 2960 FPS. Oddly, the 'new & improved' variety is 55 FPS slower.....

Kurt505 · #6 12-10-2017, 12:20 PM

Quote:

Originally Posted by jayquiver

I believe that data is from their factory ammunition.

I know for their Load Data results they use a 24" barrel for the 7mm Rem Mag and a 26" barrel for the 280ai. Perhaps they use the same length same length barrels, respectively, when testing their ammunition. But I don't know how much more velocity you get from 2" more of barrel? Perhaps thats why there is a difference.

All I know is that if I didn't own a 7mm Rem Mag I would own a 280 or 280ai.

Yes, I got the data from their factory loaded ammo. They don't list barrel length so that could be too.

The reason I don't have a 7rem mag, or a 7mm-08 is because I have 280's, lol. I've always wanted both but could never justify buying either. If I do get another .284 caliber rifle it'll be a 28 Nosler. Maybe I should say when I get another .284 because I'm getting the urge to set up a light weight long range shooter.

rembo · #7 12-10-2017, 12:23 PM

Having owned both simultaneously I can tell you there is at least 150 fps between them. The 280AI's we have top out at around 3100-3150 with a 140 in a 22" and a 23" barrel. I've had 24" 7 Rem Mags up to a comfortable 3300-3325 with a 140 and even had one hit 3400 with IMR4350. I also put a 24" Gaillard tube on a Sako for a guy in Lloydminster that hit 3400 with a 140 Accubond pushed with Rel22.

jayquiver · #8 12-10-2017, 12:40 PM

Quote:

Originally Posted by Kurt505

Yes, I got the data from their factory loaded ammo. They don't list barrel length so that could be too.

The reason I don't have a 7rem mag, or a 7mm-08 is because I have 280's, lol. I've always wanted both but could never justify buying either. If I do get another .284 caliber rifle it'll be a 28 Nosler. Maybe I should say when I get another .284 because I'm getting the urge to set up a light weight long range shooter.

I like my 7mm-08 for my soft shoulders haha

Just looked up the specs on a 28 Nosler...fast. Would be a great with 175 grain bullet for longer range stuff. Don't think I would like the recoil on that one.

Kurt505 · #9 12-10-2017, 12:43 PM

Quote:

Originally Posted by rembo

Having owned both simultaneously I can tell you there is at least 150 fps between them. The 280AI's we have top out at around 3100-3150 with a 140 in a 22" and a 23" barrel. I've had 24" 7 Rem Mags up to a comfortable 3300-3325 with a 140 and even had one hit 3400 with IMR4350. I also put a 24" Gaillard tube on a Sako for a guy in Lloydminster that hit 3400 with a 140 Accubond pushed with Rel22.

My Ackley has a 24" barrel and I'm getting the same poi with handloaded 150gr LRAB's as I am with the factory 140gr nosler accubonds out to 800yds, and it's a mild load, I assume they are traveling the same speed (have not chrono' them yet). I'm sure if I want to push the pressure up I could get them up around 3200fps, but I'm shooting about 1/2" moa with this load so I'm not changing it.

Kurt505 · #10 12-10-2017, 12:44 PM

Quote:

Originally Posted by jayquiver

I like my 7mm-08 for my soft shoulders haha

Just looked up the specs on a 28 Nosler...fast. Would be a great with 175 grain bullet for longer range stuff. Don't think I would like the recoil on that one.

Two words....... muzzle break.

Dick284 · #11 12-10-2017, 02:49 PM

You guys need to read "Why Ballisticians get grey hair"
It in the Speer manual.

Without pressure trace technology, you won't know if you're getting pressure spikes which are very common in the 7RM. (That's why load data is now relaxed quite a bit)

elkhunter11 · #12 12-10-2017, 04:11 PM

Having owned two rifles chambered in 280AI , and five in 7mmremmag, I was seeing about 100fps more in the 7mmremmag.

Pathfinder76 · #13 12-10-2017, 05:40 PM

Quote:

Originally Posted by rembo

Having owned both simultaneously I can tell you there is at least 150 fps between them. The 280AI's we have top out at around 3100-3150 with a 140 in a 22" and a 23" barrel. I've had 24" 7 Rem Mags up to a comfortable 3300-3325 with a 140 and even had one hit 3400 with IMR4350. I also put a 24" Gaillard tube on a Sako for a guy in Lloydminster that hit 3400 with a 140 Accubond pushed with Rel22.

This! And I have owned and loaded for both as well.

Pathfinder76 · #14 12-10-2017, 05:49 PM

The 280 AI is an answer to a question never asked.

Kurt505 · #15 12-10-2017, 06:06 PM

Quote:

Originally Posted by chuck

The 280 AI is the answer.

I agree.

Pathfinder76 · #16 12-10-2017, 06:15 PM

Quote:

Originally Posted by Kurt505

I agree.

So the 7mag offers nothing over the 280 but the 280 AI is a godsend? How logical. :-)

Kurt505 · #17 12-10-2017, 06:19 PM

Quote:

Originally Posted by chuck

So the 7mag offers nothing over the 280 but the 280 AI is a godsend? How logical. :-)

Are you just trying to pick something?

Go read the op, I expect a little gain in speed, and a jump in recoil.

Rather than dwell on it not being as good as your 7mm, think of it as an improved 30-06, all the recoil with an extended range!