Ackley Improved Chambers

I get a solid 200fps gain in a 260ai over a standard 260 in a 26” barrel. All of my current rifles or builds are improved variations or ackley improved of the standard cartridges.
 
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Jimbob78 said:
Why not? You may not get a big increase in performance but that shoulder angle can be made to 40 and body taper decreased
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You won't get much of an increase in performance, if any. There is little body taper and not enough case diameter for a different shoulder angle to help. That's why it hasn't been done.

It's notable that a vintage cartridge, introduced 3 years after PO Ackley was born, would come so close to his spec.
 
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MacEntyre said:
You won't get much of an increase in performance, if any. There is little body taper and not enough case diameter for a different shoulder angle to help. That's why it hasn't been done.

It's notable that a vintage cartridge, introduced 3 years after PO Ackley was born, would come so close to his spec.
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I agree it won’t produce much gain at all, but jgs or Manson will grind a reamer if one wants to chase it. It’s a 23 degree shoulder vs the typical 40 degree ackley. I’m sure someone has tried it, just like you probably haven’t seen a 6.5 prc improved 40 degree shoulder like this:



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There's been several AI cartridges thru here over the years.
7mm-08AI, 280AI, 22-250AI.. I think a 17Mk4 is a mini-Ackley.. There's prolly more.
But the 6mmRemAI is just pure ballistic sexy.. 😍😎
If a barrel's gonna shoot it'll prolly shoot bout anything well even FFing. Tuning just makes it mo'betta.. 😁
 
P O Ackley must have destroyed a lot of barrels and actions doing all of his research. I always wanted a .257 Ackley Improved but never did get around to building one. I did have a Remington 700 action rebarreled to .243 Super Rock Chucker. I could get just over 3800 FPS with a 75 grain bullet. It would vaporize a groundhog.
 
How has the most famous "Ackley-ized" and greatest cartridge of all time not mentioned yet.
The 280 ACKLEY IMPROVED 🥰

Most cartridges don't get a significant gain in velocity from being Ackley-ized but there is no real negative to doing it in most cases.

280AI next to a cute little .223 just for fun. 😁

IMG_20240327_091756280.jpg
 
Jimbob78 said:
I haven’t got my best fire forming but I’ve got plenty in the 0.2-0.3 range forming brass. AI that 223 for a real treat.
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Well, I never shoot better than .2 so maybe that's my problem. Lol

I've thought about a 223AI running 77gr SMKs. That would be slick.
 
M1Amazing said:
Well, I never shoot better than .2 so maybe that's my problem. Lol

I've thought about a 223AI running 77gr SMKs. That would be slick.
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I’ve shot a gunsmith friend’s shooting the 85.5 hybrids that was slick and very long barrel life. A lot of performance before stepping up to the swift, -250 or creed that eats barrels.
 
M1Amazing said:
I built a 7mmPRC during covid. It does really sling em. 🤤
Rocks the shoulder pretty good too with the 180s @ 2950
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I still think they should have used the 300prc case for the 7, but I know why they didn’t. Simple fix with a call to jgs or Manson
 
Jimbob78 said:
I still think they should have used the 300prc case for the 7, but I know why they didn’t. Simple fix with a call to jgs or Manson
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Lol, I think they should have done like the 7PRCW.
Short action, 6.5 PRC case, necked up to 7mm.
Being left handed short action options are much more abundant.
 
I'm just afraid the 6.5 PRC, 6.8 western, 7PRC are going to be the final blow to really knock the 280ai out. Its such a great cartridge & has such an interesting history with all its name changes and only being offered in the Remington semi auto rifle upon its initial release. Its been fighting for the spotlight its whole life. Lol
 
M1Amazing said:
I'm just afraid the 6.5 PRC, 6.8 western, 7PRC are going to be the final blow to really knock the 280ai out. It’s such a great cartridge & has such an interesting history with all its name changes and only being offered in the Remington semi auto rifle upon its initial release. It’s been fighting for the spotlight its whole life. Lol
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Blame a lot of that on long range shooting. I remember in the late 90s early 2000s we’d get looked at like we were crazy shooting 800, 1000, 1200 yards and by the early teens a mile and 2500+. People wanted more horsepower than the rem mag or 280ai could provide to push those big, high BC bergers over 3000fps and you get the stw and rum and numerous wildcats, most impressive to me being the 7mm Allen mag. Now we’ve swung to long range precision out of a box and hornady has done an extraordinary job of marketing the creed and prc. I think they both can be improved upon and have that 6.5prc reamer with a 40 shoulder.

AI were reserved for the wildcatters, the crazy guys who were going to blow themselves up. No one is pushing it like the “new cartridges” and I think it still has a cautious stigma.
 
Jimbob78 said:
Blame a lot of that on long range shooting. I remember in the late 90s early 2000s we’d get looked at like we were crazy shooting 800, 1000, 1200 yards and by the early teens a mile and 2500+. People wanted more horsepower than the rem mag or 280ai could provide to push those big, high BC bergers over 3000fps and you get the stw and rum and numerous wildcats, most impressive to me being the 7mm Allen mag. Now we’ve swung to long range precision out of a box and hornady has done an extraordinary job of marketing the creed and prc. I think they both can be improved upon and have that 6.5prc reamer with a 40 shoulder.

AI were reserved for the wildcatters, the crazy guys who were going to blow themselves up. No one is pushing it like the “new cartridges” and I think it still has a cautious stigma.
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to be fair, anything Kirby Allen comes up with is gonna be a hoot to shoot
 
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Match shooter buddy of mine used to fireform all his wildcat brass with bulk bullets and Bullseye powder @ ~10% of case capacity.
Doubt he got good groups that way tho . . . . and I'm not promoting this method . . . but he was a pretty accomplished shooter.
 
Jmoser said:
Match shooter buddy of mine used to fireform all his wildcat brass with bulk bullets and Bullseye powder @ ~10% of case capacity.
Doubt he got good groups that way tho . . . . and I'm not promoting this method . . . but he was a pretty accomplished shooter.
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I use cow method for stuff like the Allen’s but that’s the beauty of the ackley, fire form with a load of the base cartridge. Its design allows for standard ammunition to be shot accurately. In my mind this was done just for those people who ask “what happens if you’re off on a trip and can’t buy any ammo in the store”.
 
Jimbob78 said:
I get a solid 200fps gain in a 260ai over a standard 260 in a 26” barrel. All of my current rifles or builds are improved variations or ackley improved of the standard cartridges.
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Who did you have ream that barrel? I have a Tikka TAC A1 in .260 rem that shoots lights out and I am thinking of rechambering to get that extra bit of oomph out of it...
 
thaifighter said:
Who did you have ream that barrel? I have a Tikka TAC A1 in .260 rem that shoots lights out and I am thinking of rechambering to get that extra bit of oomph out of it...
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How many rounds have you got on it?
 
730ish, almost all of it factory Prime. I can track round count via the original 800 Prime I purchased when I got it. There's plenty of barrel life left, I am just trying to stretch it a bit further. I have all my data to 1300 yards and it's getting a bit boring...
 
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