.270 ackley inproved vs 270 win

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Zach321

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Hello. I'm looking at rebarreling my savage 111. It is currently chambered in 270 Winchester and my gun Smith put me onto the idea of doing a 270 ackley improved. He said that case life goes up and because I'm a reloader I can get another 1-2% of powder in the case. I'm interested in doing it but want some opinions on dies and the difference in performance.
OR
Should I go with another clambering all together? Long action savage rifle.
 
The Ackley Improved cartridges aren't worth the effort imo. There's a rule of thumb called the 4 to 1 rule. Basically, the increase in velocity will be 1/4 of the increase in powder charge. So if your powder capacity goes up 10%, the velocity increases by 2.5%. If you're only getting a 2% increase in powder capacity, you likely won't even notice the difference in velocity over the chronograph. In exchange you get to pay for custom dies and laborious case forming, either by cream of wheat method or fire forming from factory ammo.

If you're determined to go the AI route, get a .280 AI, where there are at least factory brass options and regular production dies available.
 
There is 'no need for' AI 270 when you can push a 150 grains bullet over 3000 fps with RL26 and Norma MRP, and a 130 grains to around 3100 in 270 Win.
There is a reason why the 270 Win, the 30-06, the 308, and others, have been successful for such a long time. They do what they are supposed to do. They are now even better than what they used to with new powders and new bullet technology.
 
mimile said:
There is 'no need for' AI 270 when you can push a 150 grains bullet over 3000 fps with RL26 and Norma MRP, and a 130 grains to around 3100 in 270 Win.
There is a reason why the 270 Win, the 30-06, the 308, and others, have been successful for such a long time. They do what they are supposed to do. They are now even better than what they used to with new powders and new bullet technology.
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^^^^^^ This is the answer^^^^^^
My 130 grain Nosler Accubonds average velocities are 3,357 fps, with Alliant #26, however my barrel length is 27". No signs of pressure except a little bit of primer flattening. I recently found that Peterson brass can really withstand pressure, unlike other brass.
 
I can't think of any decent reason to build a 270 Ackley Improved, other than if you just want something different, and don't mind paying $ for rare dies and fire forming. I would suggest a 7.5 twist barrel so you can take advantage of the new heavy for caliber .277" offerings
 
From the sounds of it. You guys don't think it's worth the effort. My understanding what that I'd get another 2-3 hundred FPS which I was interested in. But for what I use my rifle for, I do not need any more speed (mostly hunting). It would be mind if cool to have the AI because I've never met anyone that has one. It would be a unique rifle to own. I'm only getting 2940FPS with H4831SC and tried RL19 and got 2980FPS. But out of a stock 22 inch barrel. Using 130gn SST.
 
Zach321 said:
From the sounds of it. You guys don't think it's worth the effort. My understanding what that I'd get another 2-3 hundred FPS which I was interested in. But for what I use my rifle for, I do not need any more speed (mostly hunting). It would be mind if cool to have the AI because I've never met anyone that has one. It would be a unique rifle to own. I'm only getting 2940FPS with H4831SC and tried RL19 and got 2980FPS. But out of a stock 22 inch barrel. Using 130gn SST.
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If you want another 2-3 hundred fps in a 277 cal get another rifle chambered in 270 weatherby.
 
Zach321 said:
From the sounds of it. You guys don't think it's worth the effort. My understanding what that I'd get another 2-3 hundred FPS which I was interested in. But for what I use my rifle for, I do not need any more speed (mostly hunting). It would be mind if cool to have the AI because I've never met anyone that has one. It would be a unique rifle to own. I'm only getting 2940FPS with H4831SC and tried RL19 and got 2980FPS. But out of a stock 22 inch barrel. Using 130gn SST.
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There isn't a game animal in Canada that's going to notice more velocity than you're already getting.

Not only that, but to get the velocities you want, you're going to have to rebarrel that rifle as well, with a longer, say 26 inch tube.

Some AI cartridges actually increase perfomance in a meaningful manner and back in the day, when Parker O Ackley first started experimenting with the concept, the range of powders, with the qualities we now see as common, just weren't available.

The Ackly Improvement had a lot to do with moderating BARREL HARMONICS over velocity increases. Parker Ackley told me that personally. It was more about accuracy than velocity but in some cases the extra velocity came as a bonus.
 
Zach321 said:
From the sounds of it. You guys don't think it's worth the effort. My understanding what that I'd get another 2-3 hundred FPS which I was interested in. But for what I use my rifle for, I do not need any more speed (mostly hunting). It would be mind if cool to have the AI because I've never met anyone that has one. It would be a unique rifle to own. I'm only getting 2940FPS with H4831SC and tried RL19 and got 2980FPS. But out of a stock 22 inch barrel. Using 130gn SST.
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I have used H4831 extensively in my 270 win. it is very accurate but if you want high velocity, especially with 150 grains bullets you can uses MRP or RL26. Staball 6.5 is also an option for 130 grains.
Here is for your consideration some numbers with 150 grains bullets, which as you know have better BC and SD then the 130 grains...3030 fps with SBT 150 grains and MRP, 3050 with both ELDX 145 and NP 150 grains and RL26, 3150 fps with the same RL26 and SST 150. All from a 22.4 in Sako barrel. The +/- 3 MPBR for these is 330 yards. At 400 yards they are minus 10. Plenty enough range and power in NA for any game except the big bears. If you use bullet drop compensation, it is even better when it comes to the range because these bullets can carry enough power to 600 yards....
Ref Jack O'connor: 'I would not be surprised if the 150 bullets are the better bullets in the 270 win although I did most of my hunting with 130 grains bullets"
 
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Zach321 said:
From the sounds of it. You guys don't think it's worth the effort. My understanding what that I'd get another 2-3 hundred FPS which I was interested in. But for what I use my rifle for, I do not need any more speed (mostly hunting). It would be mind if cool to have the AI because I've never met anyone that has one. It would be a unique rifle to own. I'm only getting 2940FPS with H4831SC and tried RL19 and got 2980FPS. But out of a stock 22 inch barrel. Using 130gn SST.
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From what I understand, your intentions is not to have the extra velocities, however to have your rifle re-chambered to the 270 AI, because of the "cool" factor?
 
bearhunter said:
There isn't a game animal in Canada that's going to notice more velocity than you're already getting.

Not only that, but to get the velocities you want, you're going to have to rebarrel that rifle as well, with a longer, say 26 inch tube.

Some AI cartridges actually increase perfomance in a meaningful manner and back in the day, when Parker O Ackley first started experimenting with the concept, the range of powders, with the qualities we now see as common, just weren't available.

The Ackly Improvement had a lot to do with moderating BARREL HARMONICS over velocity increases. Parker Ackley told me that personally. It was more about accuracy than velocity but in some cases the extra velocity came as a bonus.
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interesting.

I would think that the cases that would be good candidates for being improved would be ones that have a significant taper, low angle shoulder, and long necks.

cases like the 30-30, 22 hornet, 30-40Krag.

more modern cases like the 270 the gain would be minimal.
 
woodchopper said:
interesting.

I would think that the cases that would be good candidates for being improved would be ones that have a significant taper, low angle shoulder, and long necks.

cases like the 30-30, 22 hornet, 30-40Krag.

more modern cases like the 270 the gain would be minimal.
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I won't disagree with you on the smaller cases. Straightening out the taper, increasing shoulder angle and decreasing neck lengths can increase powder capacity by as much as 15-20% with such small cases.

The 30-40 Krag has a very long neck and long taper on both the body and the shoulder, again, capacity increase is significant. Same with the 30-30 but not as significant.

I did a 338-06 improved and was actually surprised at how well it did, when compared to the standard 338-06.

The body had a one degree taper, shoulder 45 degree taper and the neck length was reduced to .250 in. The volocity increase was appx 150fps but the recoil from a 24 inch barreled Ruger No1 was more than I could handle, without developing a flinch.

I cut that barrel back on the tenon end so that the chamber would accomodate a 308 Win length case.

Did the same thing with the dies and mounted the barrel onto a 98 Mauser action.

It's a 338-08 Improved now.

Even with the one degree taper on the body, 45 degree taper on the shoulder and short .250 neck, I can't get more than about 50 fps velocity increas over factory 338 Federal offerings.

I've used 338 Federal brass to fireform in my chamber, which it does very nicely, but even when I load to maximum for my rifle pressures not a significant difference.

Very accurate rifle.

Parker Ackley's original experiments with improving already existing cartridge cases weren't as drastic as the later versions. His original intent was to stabilize harmoncs by creating a condition in the case with the sharp angle shoulders that would allow a more efficient/consistent burn rate with the off the shelf cannister grade powders available to him at the time. Velocity increase was appreciated but not the initial intent.

As you've likely noticed and suggested, some of those improvements gave significant increases in velocity, but mostly, they seem to have better predictable and repeatable accuracy, which, IMHO, is really why so many people like them so much.
 
With no disrespect to anyone I get a kick out of all the comments. Years ago when I started reloading my mentor was an accomplished marksman. He always said there was nothing to lose ackley improving a caliber. Quote from him “ it made good guns great and great guns awesome”. If your just into the improvement for velocity increase you might come away disappointed but you have to look at all the benefits. Bearhunter gave you some reasons, beyond increased speed, an AI works. Plus you get a huge increase in case life and much less trimming. Let’s face it, for a few hundred bucks in additional cost it’s pretty cheap. How many of us own more than one unneeded rifle?

Then look at those that say fireforming is a hassle. For most people, hunters, you could go to the range and fire form 60 cases in an afternoon that potentially will outlast your barrel. Then for ultimate accuracy many people fireform cases to their chamber and bump the neck, what’s the difference?

Regarding devaluation of firearm it is true, often you must sell the dies with the gun. ($120). The beauty of AI is a non reloader can shoot factory ammunition without noticing anything, a reloader, well, can reload.

And yes it has a cool factor, I would do it on that just to be different. But that’s me.

Enjoy your choice.

SCG
 
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