280 Ackley Improved ??

[turkeyeye]

I need some information.  I was reading the February edition of Handloader magazine, and there is a big write up about the 280 Remington Ackley Improved.  I have a Remington model 700 in 280 Remington.  I reload other cartridges and just haven't bought 280 dies yet.  So, now would be a good time to convert to 280 AI, and buy dies and brass for this cartridge.

From what I understand my gun can just be "reamed" for the 40 degree shoulder.  Am I correct in this?  And what does a gunsmith charge to do this?

[nomosendero]

You can't just run a reamer in there. A gunsmith will need to set the barrel back to properly ream the chamber. The price will vary with
where you live & with the individual gunsmith, I hear between $75.00-150.00 in various conversations. Good luck, you will like it & that was a good article not based on opinion alone, but real numbers.

[turkeyeye]

thanks for the reply.

[charles p]

You will not need to buy new brass.  You can fireform your standard 280 brass.  It seems to last a lot longer also.  Only drawback I can see is that the AI is sometimes tougher to chamber.  The steep shoulder seems to collide with the chamber.  Not a problem in the field for me since I probably cycle more forcefully than at the bench.

[Siskiyou]

Both Norma and Nosler manufacture .280 Remington Ackley Improved 40-Degree brass.  The next step is to find a gunsmith with the proper reamers and pilot.

Nosler factory loaded .280 Remington Ackley Improved can be purchased here:  http://www.nosler.com/index.php?p=11&b=3/&s=148


Very pricy

[wsjones]

The new Nosler Reloading Manual #6 has data for the 280 AI, which I guess isn't surprising if they're marketing brass for it.  -WSJones

[Lone Star]

You'll have to decide if the cost is worth an extra 100 fps.  Using pressure tested data (rather than just loading up until extraction gets tight) the usual Ackley Improved chamber on '06-based cases usually gives an average improvement of just 100 fps over the parent chamber.  Performance-wise you'll never see any difference in the field, but the AI cases look cool and there is nothing wrong with them....they just don't give the velocity increases that the originator (and others who sold rechambering work) claimed.


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[roper]

You'll have to decide if the cost is worth an extra 100 fps.  Using pressure tested data (rather than just loading up until extraction gets tight) the usual Ackley Improved chamber on '06-based cases usually gives an average improvement of just 100 fps over the parent chamber.  Performance-wise you'll never see any difference in the field, but the AI cases look cool and there is nothing wrong with them....they just don't give the velocity increases that the originator (and others who sold rechambering work) claimed.


.

Don't take this wrong but got to ask what pressure tested data are you talking about for the 280AI and what 06 case have you AI that you only got 100fps gain?

[quickdtoo]

The 2008 Hodgdon Annual and Hodgdon online have 280 AI data that is derived from pressure testing, they used a 24" test barrel, 1:9" twist, Nosler brass and Win LR primer.

Tim

http://data.hodgdon.com/cartridge_load.asp

[JD338]

I have a M700, action blueprinted and a Hart 24" #5 flutted barrel with a Tubb recoil lug
chambered in 280 AI.

Accuracy with the Nosler 140 gr AB and 160 gr AB is impressive. This group is with the 160 gr AB.

The 160 gr AB is very effective on WT Deer.

JD338

[nomosendero]

That is a fine rifle!!! What kind of vel. do you get with the 160?

[Lone Star]

Don't take this wrong but got to ask what pressure tested data are you talking about for the 280AI and what 06 case have you AI that you only got 100fps gain?

I won't take that wrong, I get a lot of it.    You can look in the Nosler #5 and add 50 fps for the 2" more barrel of the AI:

Bullet..velocity difference
120.........160
140...........94
150.........162
160...........71
175...........66
Average...110 fps

The Hodgdon data is tougher to compare since there is considerable pressure difference and different bullets were used:

Bullet....Velocity difference
120.........128
130.........127
140..........15
150.........-58
160.........133
162..........86
168.........131
175..........93
Average.....83

Sierra has data as well, but their testing format of rounding off to the next lowest velocity hurts comparisons; the 4" of barrel length difference also complicates things.   The AI cartridges were touted as giving much higher velocities than their parent cases at a time when virtually no one had access to a chronograph.  Some contemporary accounts said to keep increasing the load until a primer dropped out, then back off two grains!!!  Clearly if one exceeds sane pressures he can get very high velocities no matter what the cartridge, but at sane pressures the minor increase in case capacity with the typical AI design only gives minor velocity increases.  Cases which gain substantial capacity like the .25-35AI or the .250AI can see greater than 100 fps velocity increases, but not extreme increases.  The laws of physics still apply and professional gun/cartridge designers are forced have to take them into account.

Note that I am not damning the AI cartridges at all - they are still great designs which may give longer case life and perhaps better accuracy, and they do look cool.  They just aren't magic.

[roper]

Don't take this wrong but got to ask what pressure tested data are you talking about for the 280AI and what 06 case have you AI that you only got 100fps gain?

I won't take that wrong, I get a lot of it.    You can look in the Nosler #5 and add 50 fps for the 2" more barrel of the AI:

Bullet..velocity difference
120.........160
140...........94
150.........162
160...........71
175...........66
Average...110 fps

The Hodgdon data is tougher to compare since there is considerable pressure difference and different bullets were used:

Bullet....Velocity difference
120.........128
130.........127
140..........15
150.........-58
160.........133
162..........86
168.........131
175..........93
Average.....83

Sierra has data as well, but their testing format of rounding off to the next lowest velocity hurts comparisons; the 4" of barrel length difference also complicates things.   The AI cartridges were touted as giving much higher velocities than their parent cases at a time when virtually no one had access to a chronograph.  Some contemporary accounts said to keep increasing the load until a primer dropped out, then back off two grains!!!  Clearly if one exceeds sane pressures he can get very high velocities no matter what the cartridge, but at sane pressures the minor increase in case capacity with the typical AI design only gives minor velocity increases.  Cases which gain substantial capacity like the .25-35AI or the .250AI can see greater than 100 fps velocity increases, but not extreme increases.  The laws of physics still apply and professional gun/cartridge designers are forced have to take them into account.

Note that I am not damning the AI cartridges at all - they are still great designs which may give longer case life and perhaps better accuracy, and they do look cool.  They just aren't magic.

The article in Handloader dealt with a rechamber ruger 22" barrel by Sisk using Nosler 140gr ammo at over 3000fps and handload over 3000fps and if you compare that factory ammo against loading data from Nolsler # 5/6 manual you will see that the rifle in the article is getting appr 150fps less velocity and if you compare 150gr reloads you will see that rifle is around 100fps slower.  I can understand turkeyeye concern about rechambering an existing factory rifle after reading that article.  I figure you had some first hand knowledge maybe even read the article and could help him more with some real loading data.

There has been published data for the Ackley just look at Ackley own books sure they don't list pressure but for some reason Nolser,Sierra and other have published loading data for other calibers beside the 280AI with no pressure given. 

[Lone Star]

Ackley's load data is totally suspect.  He only said that he got his loads "from vaious sources."   Much of it is from the wildcat designers themselves, other is clearly lifted from published reloading manuals.  No one had pressure equipment in the 40s and 50s except a few ballistic labs - even most bullet makers used tight extraction and primer appearance to determine top loads for their loading manuals.  Today we know that practice can lead to gross overloads.

Most loading manuals do not list pressure for a good reason - many reloaders will see a maximum listed load that is 3,000 CUP under the SAAMI MAP for the cartridge so they will increase it.  Bad idea.  Data is today determined almost entirely with the use of copper crusher or piezometric equipment and max loads are as close to the MAP as the labs felt was safe.  Hornady and Sierra data is difficult to use for cartridge comparison because the max loads listed were often not even fired....they were developed graphically and rounded down.  The true max load may have actually developed 99 fps more velocity than the load listed - or only 1 fps more - you just don't know.  Manuals which list the actual velocities are more useful in making comparisons.  Since the MAP for the .280 is somewhat lower than for the .280AI, the small increase in velocity is even more distressing.....but perfectly logical.


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[nomosendero]

I think Lone Star's estimate of 100fps increase is fairly close for this particular Ackley Improved version, the increase with the AI rounds varies with the round & the difference in gain of a 250 Savage for example as opposed to a 35 Whelen is extreme indeed. Just for the fun of it I just reviewed my large stack of reloading manuals, Cartridges of the World, factory load charts, etc. If you take all of this info, the difference will be about 200fps between a 280 & a 7mm Rem. Magnum, of course if you look at a source or 2 for the slowest 280 & the fastest 7RM you can find, you may come up with 300fps which always happens in these comparisons, but for practical purposes you are looking at about 200 between these 2.  If you look at Cart. of the World & the fewer #  manuals & other reliable data that show 280AI data, you are looking at 100-125fps increase over the std. 280 for the AI. By many accounts you will be slightly more than half way between the 280 & 7RM with the AI, but let's be conservative & say it gives 100fps increase. In my view that will put you in a very good place. Only you can decide if it is WORTH IT. I have owned 3 7mmMags & shot & loaded for them alot. I now use a 300WM instead when I shoot a Mag in this range, but if I wanted a rifle in that power range in 7mm again I would go with the AI. 100fps or even 150fps is not enough to go to the belted case, the extra powder & aggravation. If I want a 7 that shoots flatter than an AI, I would go to the 7mm/300WM or 7STW & get a REALLY worthwhile gain.

The new Sierra Manual says it well concerning the AI rounds(BTW, they show a 200fps increase with the 140, a bit optimistic I think).
About the AI's, "This increases powder capacity in subsequent reloadings, which, in turn, creates the opportunity for better velocity &
higher down-range energy figures compared to the parent cartridge. In comparing a few such conversions, you will find that some deliver a surprisingly good return while others don't do quite as well. In still others they are little more than a waste of time. The factors that determine just how much "improvement" there is to an Improved case revolve around body taper & shoulder angle. By this criteria,
the 280 Remington qualifies as a fair improvement." Also, "the 280 Improved fills the performance gap between the 280Remington & the 7mm Remington Magnum. Whether this is enough to justify its existence is up to the individual shooter" Sooo, like Sierra said, it is up to you & the performance level you desire.

There are other advantages for doing this such as fewer case trimmings & a chance for a more accurate chamber than factory for example. The fire forming can be avoided now that Nosler offers the brass & ammo & now Norma. No doubt now others will follow.

Good luck!!!  

[turkeyeye]

I talked to my gunsmith and he has the equipment to do the 280AI from my 280 Remington.  The negative part is a $150.00 charge for 150 fps gain.  That is $1.00 per fps.  As much as I would like to do this, I don't see that it is very feasible.

[nomosendero]

If you fire it once.
I don't see how it could be viewed that way, if so we could never rechamber anything. And by the same token you could not choose a 22-250 over a 223, 30-06 over a 308 or a 300WM rifle over a 30-06 because the added cost of ammo or powder if you are a reloader
may not be worth it if you compute the added cost per fps. Then again, you could get a 280 rifle for $500.00 or spend a couple of thousand or more for a custom & the investment difference would be huge even though you are shooting the exact same round. Then again, the cost difference in feet per second would be lower per round if you shoot a couple of thousand rounds as opposed to shooting a couple of hundred rounds. So, I fail to understand what you mean.

But if you are saying the per. is not worth it, then it is probably isn't in your case, but for others it certainly is.
To me it must be viewed from the standpoint of performance. If the added performance reaches the level that  YOU desire, then it is worth it. The same is true for a 7-08, 7mag, STW, Ulta Mag or anything else.  Figure out what vel/performance level you seek
& then determine which cartridge, loads, barrel length, etc. will get you there. It appears to me that you don't feel the added performance is worth it & if you feel that way, I bet you are right for YOU & that's all that matters. Besides, the 280 is a great round in std. form, enjoy!!

[benchracer]

I have followed this thread with great interest, as I think the 280 is a pretty underrated cartridge.  One of the things that I never see anyone address regarding the 280 is the fact that the 280 pressure limit is lower than some comparable cartridges because the 280 was originally designed for use in Remington semi-auto and pump rifles.  I have always understood that to be part of the reason why the 270 looks better on paper, even though the 280 allows use of much more efficient 7mm bullets.  If loaded to the same pressure level, wouldn't 280 performance be closer to that of the 7mm Mag without even going to the Ackley  chamber?  I would think that with the Ackley chamber, the gap would be even narrower.  Of course, the biggest problem with trying to load 280 to 270 or magnum pressures is the lack of data to go on.  Short of fitting your rifle with a strain gage, it might not be a smart thing to attempt.  Still, from a theoretical standpoint, that is something I have been curious about for a good while.  Thoughts, anyone?

[beemanbeme]

"Is it worth it?" is a question only you can answer.  Once I have a rifle set up and a load developed where shooting it becomes kinda routine, I start looking around for another shooting project. Another rifle.
 A lot of folks buy a .280 because it's not a plain vanilla .270. It's a little different even tho it's a fine cartridge in it's own right. So why not go the extra step and have a rifle that's a little more different instead of just a little.
I didn't know AI's were supposed to be hard to chamber. I'd ask my smith and if he is a good one, he should be able to take care of that.

[nomosendero]

I have followed this thread with great interest, as I think the 280 is a pretty underrated cartridge.  One of the things that I never see anyone address regarding the 280 is the fact that the 280 pressure limit is lower than some comparable cartridges because the 280 was originally designed for use in Remington semi-auto and pump rifles.  I have always understood that to be part of the reason why the 270 looks better on paper, even though the 280 allows use of much more efficient 7mm bullets.  If loaded to the same pressure level, wouldn't 280 performance be closer to that of the 7mm Mag without even going to the Ackley  chamber?  I would think that with the Ackley chamber, the gap would be even narrower.  Of course, the biggest problem with trying to load 280 to 270 or magnum pressures is the lack of data to go on.  Short of fitting your rifle with a strain gage, it might not be a smart thing to attempt.  Still, from a theoretical standpoint, that is something I have been curious about for a good while.  Thoughts, anyone?

In the early 280 days the round was loaded very light indeed compared to the 270 & in most cases it is still loaded just a little lower than the 270. But if loaded to 270 factory pressures it still would not be close to the 7mmMag, but rather with the same bullet weight as a 270, it would or could be a hair faster than the 270, but not enough to mean anything. But obviously it would be just a little closer than it is now & this is also why the 280AI shows to be more than halfway between the 280 & 7mag when viewing all reliable data. Both are great.

[Seedsntrees]

Hello,

I have two rifles chambered as Ackley Improved. I was able to gain closer to 300 fps and furthermore, able to shoot heavier bullets with increased velocity with the Ackley Improved vs the standard 280 cartridge due to case capacity. Pressures are on the lower side. I use Reloader -22 and nothing else.

Accuracy will be increased due to the shoulder config.

This affords you two guns in one. Regular 280 for woods hunting, Ackley round for standing off fence lines.

There is nothing wrong with this cartridge, just call Nosler and ask them.

Regards,