I finished my first run through the 280 AI in the Nosler rifle. This was with 140gr Hornady SST's over H4831 powder, with 60.6gr making for the best accuracy, about 1 MOA, at a decent velocity of 2990 fps. When I went to the max book charge, the velocity increased only a little but the groups opened up to 2 MOA, so the last charge seems best. I have not started a new rifle cartridge in a while, so this was interesting to get into. I see that the 7mm bullets are pretty long, so will have to work with longer COAL and how it works out.

I always liked MRP RL22 and 7828

PM me and I will send you some 280 AI loads that I have worked up for the last 20 years.

For 140 gr bullets H4831 & Re22 are far too slow. H4350, Re17 & Re19 work far better. You should get 3200 fps with a 24 inch barrel and 140 gr bullets.

If you are looking for good deer loads, I would go for 150 gr TSX or 160 gr Accubonds.

I get 2950 fps with 160 gr Accubons and N560 - the book load from Nosler manual. Great on deer beyond 300 meters

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For 140 gr bullets H4831 & Re22 are far too slow.

Those powders may or may not do well in a particular rifle with a particular bullet, but they are certainly not TOO SLOW. I use IMR7828SSC, which is slower than either, in my STANDARD .280 with 150 grain bullets for 3040 fps. The larger case of the AI version would certainly be well-adapted to powders in this burning range.

HOWEVER, don't expect the AI version to do much the standard won't. Case capacity isn't increased that much, so at the same pressures expect no more than a 50 fps gain with the AI. Too often the velocity gains seen with improved cartridges come from simply adding powder until the anticipated velocity is reach, often at the expense of generating unsustainable pressures.

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Case capacity isn't increased that much, so at the same pressures expect no more than a 50 fps gain with the AI.

Factory 280 ammo is loaded to lower pressure than say the 270. So you can see a larger increase against factory. But hand load to hand load around 35-50fps or 1% velocity for 4% volume increase.

I beg to differ on a few counts.

BTW I am not a top velocity, hot loads guy. I tend to stop at near max with good accuracy. Safety first.

Having said that, the 280 AI is not a 49,000 cup round like its parent 280 Rem which was loaded at lower pressures for Remington semi auto & pump actions.

https://forum.nosler.com/viewtopic.php?f=4&t=27939

If you consider the 280 AI as a modern bolt action rifle round at 65,000 PSI (compared to 60,000 psi for the parent), it will safely do 3200 fps with 140 gr bullets, 3100 fps with 150 gr bullets and 2950 fps with 160 gr bullets from a 24 inch barrel. Just check the Nosler manual. Yes each rifle has its own unique likes and dislikes.

I said that those powders were too slow for the 140 gr bullets and I stick by it. In my Sako L61R, H4831, MRP & Re22 just did not give me top velocities with any of my bullets. That was my personal rifle / experience.

I got great results with IMR 4831 but that powder was not easily available on a regular basis here in NZ. They also kept changing manufacturers with variances in lots.

BTW - another reason for using slower powders in such rounds is to avoid the risk of high pressure as the case gets full. It is not uncommon to find book loads for 280 Rem 140gr bullets that are milder than a 270 Win 140 gr bullets.

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Originally posted by Stonecreek:

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For 140 gr bullets H4831 & Re22 are far too slow.

Those powders may or may not do well in a particular rifle with a particular bullet, but they are certainly not TOO SLOW. I use IMR7828SSC, which is slower than either, in my STANDARD .280 with 150 grain bullets for 3040 fps. The larger case of the AI version would certainly be well-adapted to powders in this burning range.

HOWEVER, don't expect the AI version to do much the standard won't. Case capacity isn't increased that much, so at the same pressures expect no more than a 50 fps gain with the AI. Too often the velocity gains seen with improved cartridges come from simply adding powder until the anticipated velocity is reach, often at the expense of generating unsustainable pressures.

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If you consider the 280 AI as a modern bolt action rifle round at 65,000 PSI (compared to 60,000 psi for the parent)

What is it about modifying the shoulder that strengthens the case head? Let's do apples-to-apples. We're talking about what each cartridge is capable of in similar rifles and loaded to similar pressures. The difference simply isn't much.

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I said that those powders were too slow for the 140 gr bullets and I stick by it. In my Sako L61R, H4831, MRP & Re22 just did not give me top velocities with any of my bullets. That was my personal rifle / experience.

Maybe you just didn't put enough of any of those "too slow" powders in.

I do not have the software but my memory says 5 grain capacity increase which is about 8%. Rough thumb rule at the higher end of pressure curve - velocity increase is half of powder increase - ball park - using John Barsness' old article.

That gives me 4% velocity increase above the 3000 fps with 140 gr bullet in the parent case. Minimum 3120 fps in the AI.

Definitely more than double the 50 fps you claimed.

The principle is the same for all the AI cases

Regarding the slow powders, I went to max book loads & in some cases even a bit more. I stopped when velocity gain was less an 20 fps per grain.

With VV N560 & 160 gr Accubond, I actually hit 3030 fps. I backed off 1 grain and finished with 2950 fps.

I never owned a 280 Rem but I did own a 7X64 and I found my 280 AI was at least 250 fps faster with 140 & 150 gr bullets.

I also found that the 7X64 did better with faster powders (H4350 of faster) than the 280 AI.

I appreciate the above on the merits (or lack thereof) of the AI. I had followed another thread a while back about the 280 AI before I ever had one, and one of the significant issues was the dimensions of the chamber. For some time, as I understand it, there was not a single standard for the chamber dimensions of the AI (I think shoulder angle was part of it), so gunsmiths would ream a chamber to a unique spec. Does this bear on some of the differences discussed above? I am only shooting Nosler brass in a SAAMI spec chamber in a Nosler rifle.

Nakihunter, I sent you a PM.

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For some time, as I understand it, there was not a single standard for the chamber dimensions of the AI (I think shoulder angle was part of it), so gunsmiths would ream a chamber to a unique spec. Does this bear on some of the differences discussed above?

Not much, if at all. Any version of the .280 AI is going to yield about the same enlargement of case capacity. The individual barrel (how tight, how slick, etc.) and the throating will have more impact on velocities than minimal differences in the size or shape of the chamber.

When any of us (including me) make a statement which is based on experience with just one rifle then we're like a blind man describing an elephant by feel -- how you describe it depends on which part you've got hold of.

I'm sure Naki's rifle behaves differently than mine. It is clear that the performance of my rifle shows that powders as slow as H4821, RL22, and IMR7828 are not at all too slow for a standard .280, much less a .280 AI.

And I'm puzzled by Naki's statement that he "went to max book loads & in some cases even a bit more.". Apparently whatever "book" he refers to was showing promising velocities with the "too slow" powders or else he wouldn't have been tempted to try them. Regardless, his experience simply indicates that individual rifles can behave very differently. But it hardly supports his conclusion that the powders in question are "too slow" for a .280 AI.

Sputster

I have replied to your PM

Stone creek, with respect i suggest you read my post again.

I did not say categorically that the slow powders were too slow for the AI. What I said was that they were too slow for the 140gr bullet in that cartridge. It is a well known fact that in any caliber lighter bullets need faster powders and heavier bullets do better with slower powders.

Max book loads mean the maximum suggested in Lyman & Nosler manuals that I use most often. For example I have gone 1 or even 2 grain above max with MRP as well as Re22 and had no luck even coming near the book max velocities by 150 fps. Some were even compressed loads. Could have been particularly slow lots of powder.

Such experience also comes from developing loads for the 6.5X55 in a Sako & Winchester rifle.

Here are some corrections / updates from looking at my reloading logs from 1998 onwards

Max for 139 gr to 145 gr bullets was 3140 fps using IMR 4831. The max with Re19 & N160 was 3100 fps. I got close to that with H4350 as well (ADI 2209)

With 150 gr Rem corelokt, I actually dropped velocity as it was blowing up on goats and fallow deer. I stuck to just around 3000 fps at 2 gr below max.

Interestingly my records show 160gr Accubond at 3050 fps with max N560. My friend with his 7mm WSM & 7mm Rem mag was not getting that with the same bullet! We were chronographing our loads next to each other at the range.

MRP was definitely a waste of time.

I am not able to find any Re22 records, sorry I might have confused that with some other caliber trials. Please disregard my earlier comments about that powder in this caliber.

I retired 2 lots of 50 cases after 10 & 11 reloads - one was Norma and the other was the nickel Winchester cases.

I am currently into my 3rd reload of the new lot of Winchester nickel cases.

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Max book loads mean the maximum suggested in Lyman & Nosler manuals that I use most often. For example I have gone 1 or even 2 grain above max with MRP as well as Re22 and had no luck even coming near the book max velocities by 150 fps.

My point exactly.

I'm sure you're not accusing the publishers of the manuals of lying about the velocities they obtained with their listed loads. However, in your rifle even a grain or two more of powder was 150 fps or more slower. It is obviously the difference in the rifles in which the loads were fired that resulted in such disparate velocities.

Bottom line: The manual(s) didn't find the powders in question too slow for 140 grain bullets in a .280 AI, but you did find those powders too slow in your rifle. Which is why I differ with you on your blanket statement regarding those powders. It is only in relation to your particular gun, and clearly not all .280's (either standard or AI) that such powders are too slow.

Naki's mention of the Nosler Manual caused me to look up some .280 and .280 AI loads in it.

My favorite load in my .280 standard chamber with a 24.5" barrel is a 150 gr. Nosler over 62 grains of IMR 7828 SSC which yields 3040 fps muzzle velocity (as measured by an Oehler Model 35 Chronograph with a four-foot screen spacing.)

Nosler shows a .280 AI with the same bullet using 63 grains of IMR 7828 yielding 3107 fps -- out of a 26-inch barrel.

Estimating a 35 fps adjustment for barrel length, these two velocities are only 30 fps or so apart. Of course, I may have a "fast" barrel compared to the one Nosler used, but these figures do tend to confirm that at similar pressures there isn't a huge amount of velocity to be gained with the AI.

I am not into arguments mate. Just a hobby for me & I really enjoy the "art" of reloading. Yes I know it is a science but it does not stand to reason all the time.

Just a standard thumb rule - lighter bullets use faster powders and heavier bullets use slower powders.

Yes slow powders do work on lighter bullets sometimes.

One can pick some loads to support one argument and then look at the total trend across all loads and see that the AI cartridge gives average 150 fps more velocity - not just in the 280 version buy in 7X57, 250-3000, etc.

The 30'06 is a well known example of the AI case giving better results with heavier bullets and slower powders.

Check Ken Water on Pet Loads - great reading.

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Originally posted by Stonecreek:
Naki's mention of the Nosler Manual caused me to look up some .280 and .280 AI loads in it.

My favorite load in my .280 standard chamber with a 24.5" barrel is a 150 gr. Nosler over 62 grains of IMR 7828 SSC which yields 3040 fps muzzle velocity (as measured by an Oehler Model 35 Chronograph with a four-foot screen spacing.)

Nosler shows a .280 AI with the same bullet using 63 grains of IMR 7828 yielding 3107 fps -- out of a 26-inch barrel.

Estimating a 35 fps adjustment for barrel length, these two velocities are only 30 fps or so apart. Of course, I may have a "fast" barrel compared to the one Nosler used, but these figures do tend to confirm that at similar pressures there isn't a huge amount of velocity to be gained with the AI.

I don't believe the OP asked about the merits of an AI, Since he already has one and was wanting load data.

A guy should have the rifle he wants.

Agreed with Paul. I wanted to move to a 7mm and the AI was interesting, not the norm. So will see where this goes within reason, much of the fun of reloading to me. I do appreciate everyone's experiences and opinions, they add more real life results to the book data.