I like my .280 but maybe developed a little inferiority complex so I check the Hoidgdon reloading data. I see very little increase in velocities for the 140 gr loads I shoot and the AI loads are running at a higher pressure. I think they would come out the same if run to the same pressure which should be okay in my model 70. So why would one want the .280 AI that now seems mandatory instead?
Why is the .280 AI considered to be an improvement over the .280?
- Thread starter Bill M.
- Start date
- Status
mcb
Member
280 AI has more case volume compared to the regular 280 Rem. Less body tapper and squarer shoulder. This accounts for most of the velocity performance increase between the two.
You can't compare most of the pressure data between those two cartridges from Hodgdon online data. Most of the 280 Rem data is CUP (Copper Units of Pressure) and all of the 280 AI data is all in PSI (Transducer). There is no reliable conversion.
None the less even if you load both cartridge to the same peak pressure the increased case volume of AI would allow it to have increased velocity performance.
Last edited:
sage5907
Member
I went through the same thought process when I was having a 338-06 built. The decision was to have a standard 338-06 or the AI version. After a lot of thought I decided on the standard version because I wanted to use the 180 grain Accubond at about 2800 fps and the standard version would do that. Since I was using a featherweight rifle for deer and hogs I didn't want the heavy recoil of using the heavier bullets. It was a good decision and the rifle works great. I am in the process of building a new rifle and I have been thinking about either a standard 280 or the AI version. I think that the only benefit in building the AI version would be if I was using the the heavier 160 and 175 grain bullets. That is not me because I would probably use only 140 and 150 grain bullets. I have had experience with the sharp shoulder in the past with a 25-06 improved and the standard 25-06 performed better with longer lasting cases. I had many burned through and split case necks with that rifle.
The 280 AI is one of the cartridges that gains enough to consider using the AI version. Many cartridges don't. It splits the difference between 280 and 7mm Rem mag in speed with the same bullets. About 150 fps faster than 280, about 150 fps slower than 7mm Rem mag. with 160 gr bullets.
You can also shoot standard 280 rounds in the rifle if for some reason you are limited to factory loads. Considering you get a little less recoil than 7 mag and pick up 1-2 more rounds in the magazine I'd choose 280 AI over 7 mag if given the choice.
You can also shoot standard 280 rounds in the rifle if for some reason you are limited to factory loads. Considering you get a little less recoil than 7 mag and pick up 1-2 more rounds in the magazine I'd choose 280 AI over 7 mag if given the choice.
Reducing pressure is the whole point of doing the AI conversion. By having more case volume it allows you to safely add a bit more powder to get a little more speed while keeping pressure safe.
troy fairweather
Member
For the 280 like others have said the gain is pretty good,so are the 250-3000 based ackleys. Even my 7x57 ai I can put over 3 grains more of imr4350 up to the neck of needed. You can't really go wrong having an Ackley, being able to shoot the parent round is a big plus and many guns will shot very good and not loose much fps.
With the less body taper you get less bolt thrust primers seam to show pressure later to, that normally keeps the primer pockets from opening up early. There's some thoughts the 40° shoulder keeps the brass centered in the chamber better and helps with better gas seal. The shoulder of the Ackley just about eliminates the need to trim brass.
Some will say a down side is they don't feed, but I've owed a few ackelys plus shot alot, and never had any problems. Most have been crf action to.
With the less body taper you get less bolt thrust primers seam to show pressure later to, that normally keeps the primer pockets from opening up early. There's some thoughts the 40° shoulder keeps the brass centered in the chamber better and helps with better gas seal. The shoulder of the Ackley just about eliminates the need to trim brass.
Some will say a down side is they don't feed, but I've owed a few ackelys plus shot alot, and never had any problems. Most have been crf action to.
Trey Veston
Member
My dad gave me a .30-06 Ackley Improved rifle for Christmas. I already had a .30-06. I wouldn't have ever considered the AI version since the regular one has served me well for a couple of decades. Not really into the minuscule FPS gains of boutique cartridges.
Llama Bob
member
- Joined
- Feb 25, 2016
- Messages
- 2,258
There are some cases like the .348win that gain a lot of capacity and velocity when Ackley-ized but the .280 isn't really one of them. The reasons to go Ackley:
- A little bit of case capacity
- The sharper shoulder reduces case stretch pretty much to zero - great for the reloader
- The sharper shoulder improves headspacing for improved accuracy
- The straighter case wall substantially reduces bolt thrust which lets you safely run at a higher pressure in a typical action that is bolt thrust limited rather than hoop strength limited. I'd run 65KPSI with the .280 AI no question in any action that would take say the Nosler cartridges. This gets you velocity well in excess of some published data.
Trey Veston
Member
My dad said his whole purpose of building his .30-06 AI rifle was to show that you can achieve .300 WSM velocities in an "outdated" cartridge in an "outdated" action. He gave me a box or two of loads that he claimed hit 3000fps with a 180gr bullet out of a 22" barrel. His load of 67 grains of Reloader 22 is 5 grains past what the reloading manuals recommend. A bit hot, but he knows more about reloading and big-game cartridges than just about anyone I know or have read about. He's a former colleague of Jack O'Connor and used to write for Field & Stream. My plans for the rifle will be a bit more humble and picked up some 165gr bullets with good BC for a flat-shooting deer and elk rifle.
Llama Bob
member
- Joined
- Feb 25, 2016
- Messages
- 2,258
That load is over 65 KPSI - probably more like 69 or 70 KPSI. But it's true that you can get basically the same velocity with a .30-06 AI family case that you can with a WSM case. Or at least close maybe 50 ft/s faster for the WSM. If you re-did that load with RL-26 it would be a little safer. Of course RL-26 is hard to find at the moment...
so is rl-23 which bites.....
I can get 3100 before pressure shows in my .280ai with rl-23. I haven't gone to the wall with my 06ai yet, been fighting other issues, but i hit 2925 with 178eldm and zero pressure signs. Both from 26" barrels and with 60-62 grains of powder.
I don't think there's a huge advantage to the AIs in most cases, but if there isn't any difference in cost (dies were 12 bucks, and 47, respectively) and you can shoot factory ammo, why not?
redneck2
Member
Five grains over max is pretty substantial in a case of that capacity. IMO, you’re treading into the danger zone, but it isn’t my head that’s a few inches from the chamber.
Increasing smokeless powder in a rifle increases pressure at a logarithmic rate. A 10% increase may increase pressures 50%. No way to know without test equipment. Or catastrophic equipment failure
IMO, if you want more performance (velocity), use a bigger case. Ain’t no free lunch.
Trey Veston
Member
I'm a chicken when it comes to reloading. I follow the manuals. I am perfectly content to use a 180gr bullet at 2800 fps for elk.
Newtosavage
Member
- Joined
- Nov 30, 2015
- Messages
- 2,918
Keep in mind that the .280 Rem was originally chambered in an autoloader, and therefore the factory loads, and the reloading manuals, are pretty anemic. I loaded for a .280 Rem in a Ruger 77 action and it's a great round. But if I were to do it over again, I'd get a.280AI and I'm seriously considering having my Tikka 7mm-08 rechambered to .280AI.
troy fairweather
Member
It would be easy to do, just need a new mag and bolt stop, tho a 24" barrel or longer would be better.
ThomasT
Member
John Barsness always made the point with AI rounds and that was to get a 1% gain in velocity you needed to add 4grs of powder. So in theory to add a 4% increase in speed you need to gain a 16gr increase in powder capacity. If I thought my 280 wouldn't kill what I was hunting I would just get one of the 7mm mags and be done with it. So what if you lose a round in the mag. How often have you fired more than 2 shots at game?
John Wooters wrote once that when going on a hunt in Africa he bought his wife a 280 to hunt with. He was pressed for time and didn’t get around to working up loads. So he loaded up starting loads and sighted in with those. He stated every plains animal his wife shot was killed with a single round. So what would an extra 200fps have added to that guns killing power?
John Wooters wrote once that when going on a hunt in Africa he bought his wife a 280 to hunt with. He was pressed for time and didn’t get around to working up loads. So he loaded up starting loads and sighted in with those. He stated every plains animal his wife shot was killed with a single round. So what would an extra 200fps have added to that guns killing power?
Last edited:
Newtosavage
Member
- Joined
- Nov 30, 2015
- Messages
- 2,918
Yup, but the tikka already has a 23.2" barrel, so I think that's sufficient.
Just a matter of time before I do it at this point.
- Status
Similar threads
