280 AI or .270

As a handloader I would opt for the 280 AI it has several key advantages over the 270. That said the "boring" ol 270 will work for everything you would use a 280 AI for.
 
Kachok said:
As a handloader I would opt for the 280 AI it has several key advantages over the 270.
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What are the several key advantages you see?

I see no real brass availability without fire forming, except the Nosler (expensive) brass. .270 Win is far easier to locate than .280 factory ammunition in a pinch, let alone .280 AI.

7mm does have a larger bullet selection to choose from if you include "match" bullets. As far as hunting bullets go the .270 Win has nearly the same amount and cover nearly the same range. Game animals will never tell the difference between the two rounds and neither will the shooter except on paper.

The only real advantage I see to the AI in this case is that there will be less brass to trim. AI cases just don't stretch much. Other than that there isn't a real gain in case capacity by going with the AI chamber.
 
Taylor, I agree. With the exception of the .375 A.I., I have never seen an A.I that was even remotely worth the trouble. To me, trimming is not an issue because I trim every time I size.
 
The .270 is undoubtedly a great round and available anywhere where ammo is sold.

There are more bullet options in 7mm, especially in regard to heavier bullets. Most .280 Rem. load data is help to 50,000 CUP because of the Remington autoloading rifles. In a modern bolt-action there's no reason you can't load to 52,000 CUP/62,000 PSI while the operating pressure of the .270 is 54,000 CUP/65,000 PSI. You may find that you really don't even need the AI version depending on who's loading data you're looking at. ;)
 
reynolds357 said:
Taylor, I agree. With the exception of the .375 A.I., I have never seen an A.I that was even remotely worth the trouble. To me, trimming is not an issue because I trim every time I size.
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Any case with a lot of taper to it will benifit from making it an AI case such as the H&H case you mentioned. Other notable cases that benifit from the AI process are .250 Savage, .30-30 Win, and the .30-40 Krag. Ackley himself never saw much gain in improving the 06 case.
 
Thanks for all the input guys. It's great to hear varying opinions on the use and effectiveness of these two cartridges. I'm not ready to drop any cash just yet, possibly in the next couple months though.

Thanks again.
 
I'm in central PA. All the gun shops around here seem to be well stocked on components. The çartridges are hard to come by around here but it's getting better.
 
taylorce1 the advantages I am talking about are reduced trimming and longer brass life thanks to the reduced stretch of the sharper shoulder. The AI is capable of getting within 100fps of the 7mm Rem Mag which is noticeably more powerful then the 270 though being so close in caliber they are clearly capable of the same game. If you had to give the edge in long ranged accuracy to either it would have to be the 280 AI, sharp shoulder cartridges (25 degrees of sharper) have always ruled 600 and 1,000yd matches (6mmPPC/BR/Dasher, 7mm Rem Mag, WSMs, 6.5-284, 300 Win Mag....etc) not that the 270 is any kind of slouch and is plenty accurate inside realistic hunting ranges (within 300 yards).
The one key advantage of the 270 is simple, brass is everywhere, I have a bucket full of once fired 270 that I have not even touched yet and did not have to pay a nickle for any of it.
 
What weight bullet can the .280 get within 100 FPS of the Rem mag. with all other things being equal? Assuming it can do it, at what pressure is the A.I. and at what pressure is the Rem mag? Keep in mind that any pressure that is unsafe in the Rem Mag is also unsafe in the A.I. Many times the Wild Cats go super fast only because they are being loaded super hot.
 
Since you're talking about the .280AI I'm assuming you'll be reloading. The .280 wins hands down in that case. I love the .270 and own one but the 280 is more efficient and generally has better bullet weights and being that it will be AI, it has more powder capacity than the .270win

Unless you get a rifle with a custom twist and use 165 or 175 grain Matrix bullets in the .277, the 180 grain bullets in the 7mm will outperform the 150's in the .270win.
 
Both of them are excellent cartridges,both do the job.If a person says "I prefer(either)" They do not need to justify the choice.

The greatest difference between them boils down to the standard rifling twist is a bit tighter on the .280,so it can handle heavier for caliber bullets.This translates to potentially better long range performance for the 280.

Its fair to ask how much over 400 yd shooting will be done.

I believe the .270 was a product of the 1930s.Nothing wrong there.At that time,and on up through the 70's,most scopes had plain crosshairs,or post and crosshair,or dot,reticles.Most scope adjustments were just OK to mediocre for sighting in,and not practical for adjusting for range.

Where marketing took cartridges was light bullets over 3000 fps.Easy on the shooter,great lethality in the boiler room,and an easy to use flat trajectory out past 300 yds.

Now,reticles ,target knobs,I-pads,lasers,etc along with higher BC hunting bullets mean a 2800 fps load with a .635 BC bullet can be used effectively at longer ranges than a .430 BC bullet at 3100 fps.

A lot of folks just don't care,and a 270 works better now than it ever did before.

My preferences,I'd probably go .280/7mm express.AI? Likely,but maybe not.

I'm not keyed toward longer ranges these days.

I think I'll use my cloned up 1903A4 with a 2.5 x scope antelope season.Just because.Maybe its "better"???

Oh,and,looking for ammo,try 7mm Rem Express.
 
Unless you get a rifle with a custom twist and use 165 or 175 grain Matrix bullets in the .277, the 180 grain bullets in the 7mm will outperform the 150's in the .270win.
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If you want to shoot 160 to 180 grain bullets, you're looking at the wrong cartridges, to begin with.

If you want to shoot that weight class, increase the bore size and step up to .30 caliber. You're just handicapping the cartridges, if you do that in .270 Win or .280 Rem.
 
If you want to shoot 160 to 180 grain bullets, you're looking at the wrong cartridges, to begin with.

If you want to shoot that weight class, increase the bore size and step up to .30 caliber. You're just handicapping the cartridges, if you do that in .270 Win or .280 Rem.
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I disagree. Those weights in the smaller calibers have an advantage since smaller diameter bullets of equal weight tend to have better BC's and SD's than a bullet of equal weight (and similar shape) of a larger diameter.
I am interested in the heavy for cal bullets due to their better BC's for long range.
If we compare a 175 grain in the 7mm-06 and 30-06 the '06 has a slightly higher muzzle velocity(2725fps vs 2680fps) but the 7mm's better ballistic coefficient gives it the advantage at long ranges. If you just want the extra weight for more punch, then the .308 diameter is fine and can go much higher in bullet mass (up to 250grains)
I'd hardly call the .270win and .280rem 'handicapped' with heavier bullets.
What's wrong with the .277 shooting a 180 grainer at 2500-2600fps, or the 280rem shooting a 180 at 2600-2700fps. The 06 is slightly more efficient and pushes a 180 to around 2700-2800fps, but it's going to lose it's velocity faster assuming all the bullets have a similar VLD shape, and have similar core material
 
Kachok said:
The AI is capable of getting within 100fps of the 7mm Rem Mag which is noticeably more powerful then the 270 though being so close in caliber they are clearly capable of the same game. If you had to give the edge in long ranged accuracy to either it would have to be the 280 AI, sharp shoulder cartridges (25 degrees of sharper) have always ruled 600 and 1,000yd matches (6mmPPC/BR/Dasher, 7mm Rem Mag, WSMs, 6.5-284, 300 Win Mag....etc) not that the 270 is any kind of slouch and is plenty accurate inside realistic hunting ranges (within 300 yards).
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The problem with your 100 fps argument is that you're forgetting the .270 is often within 100 fps of the 7mm RM as well. Simply because the .270 is loaded to higher pressures than the 7mm RM. The .270 is often loaded to 62K psi where the 7mm RM is often around 55K psi. Crank up the powder and neither the .270 or .280 in any version can touch the speed of the RM.

As far as the 7mm RM being noticeably more powerful I haven't seen it. Nor have I seen animals react noticeably different when hit with a bullet out of the .270 or 7mm RM. I'm not going to argue the 7mm RM isn't a more powerful cartridge, but it isn't going to make any difference like you stated.

I'd argue that the .270 is plenty accurate outside of 300 yards as well. Longest shot I've successfully made shots well beyond 300 yards with the .270. In fact my largest mule deer buck to date was taken with a .270 Win just north of 560 yards.

The standardization of the .280 AI wasn't because it is more accurate because of the shoulder angle. It was to correct the mistake made by Remington, and it wasn't because the pumps and auto-loaders couldn't handle the pressures. It was because if they loaded the .280 Rem to 62K psi like the .270 it was way too close to the already popular 7mm RM.

I'd also argue there are other features that make the other cartridges you mentioned more accurate than the shoulder angle. If changing a shoulder angle was all that was needed to make a more accurate cartridge it would have been done a long time ago to most other cartridges. Changing the shoulder angle was more of a benefit as already agreed upon in prevention of case stretching and trimming.
 
Since my 280AI is chamber for the SAAMI spec 280AI I'm not sure how anyone could call it a wildcat.

Myself I don't have pressure testing equipment to check my loads so be pure speculation on my part quoting something. I don't like to compare as my 280AI is just that and I'm sure as others have found out some bullets/velocity may overlap another case.

Their guys shooting F-Class open with 284 @ 1000yd with 180gr bullets @ 2900fps plus.
 
I'd hardly call the .270win and .280rem 'handicapped' with heavier bullets.
What's wrong with the .277 shooting a 180 grainer at 2500-2600fps, or the 280rem shooting a 180 at 2600-2700fps. The 06 is slightly more efficient and pushes a 180 to around 2700-2800fps, but it's going to lose it's velocity faster assuming all the bullets have a similar VLD shape, and have similar core material
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What's wrong with a .270 Winchester shooting a 180 grain bullet, is that your velocity figures are highly optimistic and unachievable in the average rifle. In reality, the velocities of a 180 gr projectile are more like 2,300-2,450 fps (even 2,500 fps can be difficult to achieve).

Even with the extra case capacity and higher pressures allowed in .280 AI (versus standard .280), you're still lucky to be able to hit 2,600 fps with a 175 gr bullet.


And, arguing about ballistic coefficients doesn't do much good without some actual comparisons.
How about a "best case" .270 load against a "worst case" .30-06 load with bullets of nearly identical BCs :
.270 Win Wooleigh 180 gr (0.512 BC) @ 2,500 fps - At 1000 yards: 1193 fps / 485" drop / 98" drift / 569 lb-ft energy
30-06 Sierra GK BT 180 gr (0.507 BC) @ 2,700 fps - At 1000 yards: 1282 fps / 412" drop / 89" drift / 657 lb-ft energy

The .30 caliber projectile has a huge advantage with the increased muzzle velocity. It is farther from destabilizing (subsonic transition), drops 73 inches less than the .277" projectile, drifts 9" less, and retains 15% more energy.

Even if you turn to a "best case" .280 AI vs "best case" .30-06 for the same comparisons, the results still favor the .30-06 for nearly anything in the 170-195 gr weight range.


If you REALLY want to build a .270 or .280, go for it. But don't worry about things like down-range efficiency, unless you actually run comparisons to verify your assumptions.
 
I don't see the 270 running within 100fps of the 7mm Rem Mag in the same bullet weights, a 270 Win maxes out a 140gr at around 3,000fps whereas my Nosler manual lists 7mm Rem Mag 140gr loads over 3.300fps both in a 24" tube, I would call 300fps difference noticeable to say the least. The 280 AI maxes out a 140gr at 3,265fps using RL22 a long standing favorite powder of mine.
 
The velocities given are with the Rem mag running 5k psi less than the Ackley. There is nothing in the design of the brass or the actions that necessitate the Rem mag be loaded to lower pressure than the A.I.
 
Kachok said:
I don't see the 270 running within 100fps of the 7mm Rem Mag in the same bullet weights, a 270 Win maxes out a 140gr at around 3,000fps whereas my Nosler manual lists 7mm Rem Mag 140gr loads over 3.300fps both in a 24" tube, I would call 300fps difference noticeable to say the least. The 280 AI maxes out a 140gr at 3,265fps using RL22 a long standing favorite powder of mine.
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There is the problem you're cherry picking data. First off if you look at the load data for the .280 AI in the current Nosler manual they load densities are all around 90-110% case capacity. The .270 and 7mm RM is running aournd the 80-90% load density range, and in the 5th edition Nosler manual the .280 AI was running about the same. What changed between the 5th and 6th edition? Nosler introduced the .280 AI as a commercial load and in the semi-custom rifles they produce and are trying to sell a product.

If you look at other load manuals that have load data for the .280 AI like Hodgdon they run the AI at 60-62K psi same as the .270 Win and guess what? They perform similar with the same weight bullets. This is another thing that throws up a red flag for me. How is it that Cooler is the only manufacturer whose .280 AI data is producing such velocities? My guess is by the time the next edition of the Nosler manual comes out we'll see the load densities and velocities backed off from the current edition.

Now getting back to Nosler's data most the 7mm RM loads that are most accurate for it with the 140 don't even get close to 3,300 FPS they are in the 2900-3000 fps range. I dont' have the 7mm RM anymore but I do load the .270 and can tell you that I can get 2800-2900 fps pretty easily out of the 140 grain bullets. I load as well for the .280 Rem and 2800-2900 fps is all I need out of the .280 and 140's.
 
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