.270 Ackley Improved
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MagnumManiac
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To be completely honest with you, the 270 is the last cartridge I would AI!
It has all the velocity you could want in that size case, it really is the first magnum.
If you want more performance, do what I did and re-barrel to 270Weatherby, now this is one cartridge worth all the hype!
It will push 150gr bullets as fast as the 270 can push 110gr bullets! Albeit with a longer barrel of course!
There really is not much gain to be made by AI'ing the 270, it will all likelyhood only achieve an extra 50fps, maybe a little bit more if you're lucky.
It has all the velocity you could want in that size case, it really is the first magnum.
If you want more performance, do what I did and re-barrel to 270Weatherby, now this is one cartridge worth all the hype!
It will push 150gr bullets as fast as the 270 can push 110gr bullets! Albeit with a longer barrel of course!
There really is not much gain to be made by AI'ing the 270, it will all likelyhood only achieve an extra 50fps, maybe a little bit more if you're lucky.
Long Time Long Ranger
Well-Known Member
I have an AI or improved wildcat in about everything but 270. Everyone I ever talked to about it said it was the least favorable to AI because for some reason there is no appreciable gain for some reason with the 270. I can't confirm this because I never tried it. But that is what I have been told by several who have tried it. Makes no sense to me. I agree that the 270 wby is awesome. Mine shoots a high BC 150 grain bullet 3300 fps which will take down about anything.
The only 270 calibers I have are the 270 winchester and the 270 wby. I figure that covers it. In between I would just do a 270 wsm instead of the 270 AI.
You might consider the 280 AI which you will be very pleased with instead of the 270 AI. The 7mm gibbs and 7mm JRS are right on the heals of the 7mm rem mag and will do anything the rem mag will do. With the 7mm bullets available the 280 AI is one of the better AI chamberings for hunting.
The only 270 calibers I have are the 270 winchester and the 270 wby. I figure that covers it. In between I would just do a 270 wsm instead of the 270 AI.
You might consider the 280 AI which you will be very pleased with instead of the 270 AI. The 7mm gibbs and 7mm JRS are right on the heals of the 7mm rem mag and will do anything the rem mag will do. With the 7mm bullets available the 280 AI is one of the better AI chamberings for hunting.
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Jamie6.5
Well-Known Member
According to the re-print of Ackley's published improvements here:
Article posted on Precision Shooting Website about Ackley Improved cartridges - Shooters Forum
The .270 is listed twice. Most likely with different weight bullets. The velocity increases Ackley realized were listed as 7.8%-8.8% range.
Either one of those increases is pushing the .270WSM velocities.
I wouldn't mind getting 150gr SSTs or Interbonds (.525BC) up around 3100fps.
Plus, the case life and lack of case trimming would be worth it IMHO.
The .280AI has similar gains and it's popularity has skyrocketed in the last few years.
Article posted on Precision Shooting Website about Ackley Improved cartridges - Shooters Forum
The .270 is listed twice. Most likely with different weight bullets. The velocity increases Ackley realized were listed as 7.8%-8.8% range.
Either one of those increases is pushing the .270WSM velocities.
I wouldn't mind getting 150gr SSTs or Interbonds (.525BC) up around 3100fps.
Plus, the case life and lack of case trimming would be worth it IMHO.
The .280AI has similar gains and it's popularity has skyrocketed in the last few years.
Long Time Long Ranger
Well-Known Member
The 280 AI is the same bolt face and will work perfect on your action. There are many good choices in 7mm high bc hunting bullets. Very limited in 270.
royinidaho
Well-Known Member
I 'think' I recall a thread awhile back by someone with a very long drop tube filling the Win case with IMR 7828 (probably ssc) and getting wonderful velocity, accuracy and case life.
I haven't caught on how to do a search on more than one word thus can't find it.
Velocities in my 270 Win, w/140 class bullet are limited to 3200 FPS because that's a velocity I'm very comfortable with and case life is forever. (27" Lilja bbl)
The other 270 is an Allen Magnum w/the 150 class bullets zipping along at 3650. Kind of cool but really unnecessary as it was made for a bit heavier bullets.
I haven't caught on how to do a search on more than one word thus can't find it.
Velocities in my 270 Win, w/140 class bullet are limited to 3200 FPS because that's a velocity I'm very comfortable with and case life is forever. (27" Lilja bbl)
The other 270 is an Allen Magnum w/the 150 class bullets zipping along at 3650. Kind of cool but really unnecessary as it was made for a bit heavier bullets.
If i can't get much more velocity out of the .270 AI would it at least be more accurate? I was thinking of using the 150 gr berger VLD which seems to have a good BC and an all around good bullet from what I have read.
Or would a .280 AI be the better route?
Or would a .280 AI be the better route?
Long Time Long Ranger
Well-Known Member
Jamie6.5 info he posted sounds more like what I would expect from the 270 AI. I could never figure why people were not getting the numbers out of the 270 AI when the others, which I have, do very well. Like I said I have never done the 270 AI so I don't know from first hand experience. What I do know from experience is I would go with the 280 AI over the 270 for better bullet choices in quality high bc hunting bullets. I like it better as an all around big game round you can hunt about anything with because of all the 7mm bullet choices. It will do anything the 7mm rem mag will do. You will come in about 100 fps under the 7mm rem mag which is trivial. No animal will ever know the difference. The 280 AI is one of the best out there and there are probably quite a few guys on here that shoot them who can testify to that. I have one and also the 7mm gibbs and 7mm JRS. I would feel comfortable hunting anything with either of them. I also have a 270 winchester and two or three 270 wby mags. I have taken game to 1100 yards with the 270 wby so I am not saying the 270 is not good either.
From what I've read the lackluster performance of the .270AI had to do more with the limited powders available at the time Ackley was experimenting with it; although the IMR7828ssc mentioned is certainly a modern concoction. I would like to see some data with it and some more of the latest powders. All that being said the 280AI is a fine choice with the same case head.
Thanks for the help I'm not sure what i want to do yet but the links are a big help. Now the main reason I think I might go for the .280 AI over the .270 AI is better bullet choice like Long Time Long Range said. But I live in TX though and our deer are small HA, I don't think I need that big of a gun.
