Home Forums Hunting & Shooting Ask The Gunwriters 280 AI and 270 AI

After building and hunting with 257AI, 257AIR, 250KragAI, I would say don't AI [Ackley Improved] anything. It takes an extra step of fireforming.


But the 280AI has Nosler brass available.
https://www.midwayusa.com/product/1021411695
No wasted time on a extra trip to the range.

I Have a 270 AI, fun to do it, picked up some speed. But is it worth it? Sits in the safe, running a .257 weatherby.

No doubt this was also in part due to the more limited selection of slow burning powders available at that time. That is not to say that I am suggesting it is worth doing today. I have a 6mmAI and appreciate what I learned about reamers and reloading while working with it but I would not do another one.

Many people when they go AI are wanting the most form a cartridge. They also will make changes to the reamer design to better suit brass dimensions, and bullet position in relation to the shoulder/neck junction on the brass. Brass trimming is over when you go AI.

I have seen note worthy increases in speed with extremes in accuracy with:

223 AI
22/250 AI
243 AI
6 Rem AI-long action case at it's best

Figure 200 fps increase(223 AI-150 fps increase), and none of them are short barrel rifles.

I have shot out quite a few barrels with the parent cartridge with target chambers, then went to the AI version. I never felt like there was a down side to the AI version in the above. I was usually fire forming on Small varmints or Coyotes. Fire forming loads are very, very accurate.

The only big game cartridge that I have played with is the 280 AI.

In the std 280, I shoot the 160g partition at 2930(IMR 7828 with a Fed 210 giving the best accuracy), a load right out of the #4 Nosler manual. In the AI, that same bullet is doing 130 fps faster, R#26, Lapua 30/06 formed brass, 26" barrel vs 24" on the std 280. I now run the 175g ELD-X in the 280 AI. Some would argue that running the 162g ELD's in the std 280 would be prudent vs going AI, and I can not argue with that train of thought.

When I lived in Az, I met a gentleman at the rifle range that was shooting a 26", 30/06 AI, 180's at 3000 fps verified with my Ohler 35P chronograph. The accuracy was very impressive with his 30/06 AI with the 180g Sierra BTSP and 180g Nosler Partitoins., I did not know his load or particulars on chamber dimensions other than he was shooting Winchester brass. I saw the gentleman shoot his 30/06 AI often, and it was impressive to say the least out to 500 meters.. Up until that time, I thought that the 7/08 AI, 7x57 AI, and 30/06 AI were a waste of time, but that one gentleman made me question my closed mind. I have purchased the 7/08 AI dies, reamer, and barrel.....as far as I have got in 5 years.

AI shooters are often using Lapua and Alpha brass parent cases to fire form with, and I use 14.6g of Bullseye with cream of wheat to fire form my 280 AI brass from Lapua 30/06 cases. The primer pockets on the Lapua '06 brass is so tough it is hard to believe. There is no doubt that 100 cases will last a barrel's life time.

I found the Lapua 22/250 and 243 brass to be very tough also when it relates to tough primer pockets, with Federal brass in all AI's being solid junk.

Rifle loonies are often chasing the smallest details on trying to get the most accuracy with velocity, it is a hobby with in a hobby no doubt.

As we see advances in the BC of bullets, there are some combos that are simply mind boggling, and the std 280 Rem, with brass formed off of 30/06 brass, with a 180g ELD-M is simply a game changer. R#17 with a cci 250 with only a little powder can replace a lot of magnum cases, and is killing deer and hogs, 2700 fps on a bullet with a BC of .800 sheds a lot of light.. I am running a Bartline 3b, 5R configuration, 8T barrel, at 24" in one std 280, and factory 280's in others.

Running quality brass with High BC bullets replaces a lot of BS, AI or no AI. Good chambers that take into consideration neck clearance and bullet geometry is a game changer if you are wanting to shoot to 600 yards with extremes in accuracy. Taking Magazine length into account when considering the Cartridge Base to Ogive pays some big dividends, choose wisely and consider how the leade grows 800 rounds from new chamber.

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The AI offers an advantage in only magazine capacity. For a hunting round I can't say having 3 in the mag ever was too little for me when I have carried magnums from 7MM Mags all the way up to 458 mags. So that advantage may be more a "good feeling" then a real world advantage. Heck, I have often hunted with single shots and still never found them to be at a disadvantage. But extra rounds in the mag can't hurt.

If ballistics are what is being pursued, (more speed) the 270 Short Mag, or 270 Weatherby both beat the 270 AI and do so with FAR less bother. You can buy brass for them both and not have any need to fireform first.

Same with the other AI shells.

257 AI vs 257 Weatherby or for that matter the 25-06, So in the case oif the 25-06 even mag capacity advantage is non-existent. 25-06 holds just as many rounds in the mag and does everything the 257 AI does and sometimes a bit more.

6.5 AI VS the 264 Win mag---- and nowdays several other hot offerings.

30-06 AI vs any of the many 300 mags, all of which beat the AI in velocity.

AI is more of a fun game for those that like fireforming, messing with brass as a hobby and for some, bragging about how "advanced" they are in their understanding of rifles. But for practical use, they offer nothing you can't buy off a gun-shop wall, and the ones you can buy from a local gun shop (or even Walmart) give HIGHER velocities without needing to buy more expensive dies and use up powder and primers to fireform.

I read all the great things about the 280AI. I already had 280’s.
The rifle I bought was a gunsmith build with blue printed 700 action 26” premium varmint barrel etc.
So far my old 700 280 with a stock I carved (not well BTW) shoots tighter groups. But I’ve shot a lot of paper with that rifle.
I really have not spent time and have shot < 1 MOA groups with the 280AI but I expected more and the rifle is pretty heavy even in the light Kevlar stock. I’ll likely try to ring it out this year.
I don’t think I should have spent the $’s what that 280 AI cost. I already had a couple 7mm RM and I didn’t need the extra 50 or 60 FPS from the AI over the 280. I might shoot a lot more at paper with my hunting rifles than most, but the stretching of cases with a 280, I think, is over stated.
As far as 270 shooters, most seem to think they already have the perfect cartridge and there’s no better than perfect.

what about Charles Newton`s 256 Newton anyone do any of the new type powders ? and have some velocities with bullet sizes or how does it compare to these other cartridges posted on this site ? i have been thinking about chambering a rifle in this neat old cartridge. what i really would like to do is have a Ruger # 1 with a Brux barrel 8 twist 26 inch length chambered in a 256 Newton ,its just a dream so far. i did have a 25 Wallok and Holmes rifle using a 270 Win.case but rebarreled this rifle to a 257 Roberts for my daughter. also thought about a 6.5 / 270 Win. A.O. instead of a 256 Newton ? there sure are a lot of options out there to play with . my good friend Greg a a very good machinist and bench rest shooter rebarreled a rifle too a 280 A.O. and after a couple of years wasn`t that excited about the 280 A.O. anymore said it was accurate but just wasn`t his thing anymore. so maybe i may just stay with what i have been using ?

I have done the AI thing several times, and the only advantage I could find was in less case-trimming--sometimes.

My first one was .257 Roberts AI in a New Ultra Light Arms Model 20, with a 24" barrel. It shot very well, and I could see the added velocity on the chronograph, but never could see any advantage in "killing power" or trajectory, because it only got around 100 fps more than the standard .257 when loaded to the same pressure.

Have also had a couple of .280 AIs, and also never could find any advantage there either. Both were very accurate, but so have been my standard .280s--and my .270s.

There was also a .35 Whelen AI, a used Remington 700 Classic that somebody had punched the chamber on, thereby cutting the rifle's resale value in half. (Some shooters pay a LOT for unaltered Classics.) I figured it was worth playing with, and also quickly figured out the .35 Whelen AI was just about useless, because the added capacity gained by blowing out the minimal shoulder of the parent case didn't mean anything. (Had never had any trouble with headspacing in standard .35 Whelens either--another claim of an advantage in the AI version). So I "parted out" the rifle, selling the barrel, stock and action separately, actually making more money than I paid for the rifle.

The last AI I fooled with was a .223, because so many people talked about the great velocities, some claiming to get close to .22-250 zip. I found the extra powder capacity gained (measured with the water method) wasn't enough to get .22-250 velocities at the same pressure, so I ran a test with a standard .223, adding more powder until "pressure signs" showed up. Guess what? With the zippiest "safe load," muzzle velocities were just about what most people claim for .223 AIs. This was because my handloads were getting a LOT more pressure. (Traditional "pressure signs" often don't show up until around 70,000 PSI, something I determined with the help of the folks at a piezo-electronic pressure lab years ago.)

Eventually I concluded that most of the extra velocity from AI rounds is due to their being handloaded to higher pressures than the parent case--though of course some compare their AI handload velocities to factory load velocities. This is why the .250 Savage AI is claimed to be such magic: The SAAMI pressure maximum pressure for the .250-3000 is really low.

Also decided the only real advantage at AIs is less case stretching, due to the sharper shoulder headspacing firmer in the chamber. But a lot of newer rounds have steep enough shoulders to do the same thing, right from the factory.

Maybe one interesting thing some manufacturer could do is get a saami approved 270 AI with fast twist to take advantage of heavier bullets coming out for the 270. Since apparently it is too confusing for them to just fast twist a regular old 270 or 270 wsm. Kind of ride on the 280 AI, high bc, plus new military round trend

Have you heard of the 6.8 Western?

Ha, yep. I have one. Competition, however, is healthy from what I hear

Lou

I was going to improve the .270 with a 30 degree shoulder and take the diameter out to about .454 for a mild improvement that would still ensure good feeding. Unlike the .280, the .270 with its longer neck gives too long a neck if you want to headspace a standard .270 case in the improved chamber to fireform the case. You can of course trim the neck for a shorter case. If you have the improved case's neck shoulder junction higher than the original junction and gain a slight increase in power space, then you have to create a false shoulder by necking up to 30-06 then back down to .270 Improved or fireform by jamming a bullet seated out further into the lands. Neither of these methods are as desirable or as safe as being able to fireform an unfireformed case that headspaces correctly. With the .280, this problem doesn't arise.

A tad confusing, but sounds like you’re trying to set a false shoulder for forming to a 30 degree Improved case.
I’m not sure if the 280 std case differs that much with its shoulder only .050” forward compared to 270 Win

Taking advantage of these new Quick Twist barrel / bullet designs is most tempting. No point launching the big long heavies in anything less than an Uber Improved case.

Have a look at drawings for the SA CreedMoor, it has a shoulder diameter of .462” giving minimum body taper, Combined with that desirable 30 degree shoulder for pressure consistency.

The longer the neck, the better for protection from throat erosion , Plus tons of latitude for seating depth.

I’ve been thinking along these same lines for my LA 275 Improved Express BangN Thunder Uber Improved Cat

Cheers

To me the '06 based cartridges are great candidates to AI, assuming the rifle will feed them. I wouldn't take a good shooting .270 or .30-06 and ream to AI, but would do so upon rebarreling a rifle that I planned to rebarrel anyway. Outside of feeding, and most of my CRFs feed AIs fine, I can't think of a disadvantage.

Loaded to normal pressures, in theory, the AI brass should last a long time without much stretching, which eliminates one step when reloading and I'm all for that.

I fire-form factory loaded ammo in AI chambers for brass and generally without much loss of velocity or in the case of the .280 AI, I just buy brass. I have in fact, fire-formed ammo on animals while hunting!

I don't expect AI cartridges on an '06 cartridge to produce much more velocity than the original and really don't try to achieve it.

If the neck is too long, my concern is too much grip on the long projectiles and too much pressure. If you increase the shoulder diameter in a .270 much more than around .454", then you start to run the risk of compromising very smooth feeding.

6.5 CM feeds well. Does it feed better than the Swede ?
Probably depends on the action just a bit. Many of those actions were designed specifically for one cartridge only.

The 222 Rem has a very long neck ( for caliber ) , yet produces stellar accuracy. Neck tension is more about sized diameter, and neck thickness.

It’s really not that big of a difference from the 280 AI case for a 270 Improved. PO. Ackley didn’t recommend it because of the basic 270 Win cases pressure level. Hence the RPM, and 6.8 Western cases

Great thread - enjoying the context that JB adds. I’ve got several 338-06’s now & considered sending an AI reamer thru one of them but I think I’ll serve my serve inner loony by sending the rifle to JES for a rebore to 9.3x62 instead of the AI path.

You’d like a 9.3x62 I think. I love Whelens but since I had a few and got a stinker of a Hawkeye in 280 I decided to try the 9.3. It has been a silly easy cartridge to work with, just like the Whelens.

Pints : Does the 9.3 x 62 clean up a .338-‘06 ? AI ?

Who wouldn’t want one of each ? Smooth feeding of course.
CZ made a mistake discontinuing the 550, at least in that chambering.

Not to torpedo Rolly

I don’t know if a 9.3x62 will clean up - I’m assuming it/they would but I have no facts to back that assumption. I’ll have to call JES. I’m with you on owning both! The rifle is a Douglas barreled Ruger 77 but after buying my Weatherby ultralight in 338-06 it doesn’t see any field time.

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