Ackley Improved

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Bulldog, May 10, 2009.

  1. Bulldog

    Bulldog Member

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    hello everyone,

    I want to know more about the AI....

    Case life,
    velocity gain %,
    which if any cartridges are a complete waste of time?

    You know we all head to the range looking for an edge. Whether or not it's better accuracy or more speed or both!

    So the way I look at it is if a guy can get even 100fps more and still be accurate with supposed better case life whats not to like?? It's still gotta feed great.

    So I really would like to know from .22 clear to .338 AI who's got one? Was it worth it? Would you do it again??

    Thanks alot guys
     
  2. TAP

    TAP Well-Known Member

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    I had a .223 AI and loved it. Had a 1 in 8" twist with a 26" Lilja 3 groove. Shot about 200fps faster than standard. I just neck sized and case life was very good. Only had to trim about every 5 firings. I currently have a .257 AI. Shoots sub MOA and about 200fps faster with 100gn NBT. Accuracy is sub MOA and again, I only have to trim about every 5 firings. Same with f/l resizing. No feeding issues with either round. Both in Remmy 700's. Have a .338-06 AI and a .280 AI planned in the next couple of years. Love the AI's.
     

  3. Bulldog

    Bulldog Member

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    How much improvement (velocity) did you get with the 338-06??

    Any feeding issues??

    I have an old -06 springfeild with a barrel thats toasted. have been thinking either 30-06 AI or 338-06.

    Call me crazy but I'm head over heals about the new Hawkeye in the RCM.

    338RCM AI?? Wanting to push 225-and 250ammo to 338wm velocitys. I'd leave it unscoped and maybe(maybe) add a peep site. (brush thumping elk and bear!!)
     
  4. ICANHITHIMMAN

    ICANHITHIMMAN Well-Known Member

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    Just my two cents but if your going to leave it un scoped and use it as a brush gun why go to all the truble of pushing the bullet so much faster?

    You will have shorter barrel life and feeding could be an issue in the springfield. Aslo I am no metal guru but I do know that the old 06 is safe for that much presure.

    I think one of the smith could awnser that.
     
  5. CliffM

    CliffM Well-Known Member

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    Good morning,
    I have an old savage rifle that I discovered had a 14 twist and it was hard to find bullet or load that would stay on a paper plate. I put a 10 twist Douglas barrel on and had it chambered in .250 Savage Imp. From dark to daylight! Fire forming loads would put everything tried into 2". My goal was to be able to shoot 100 gr. bullets at 3000 fps. I have gone up to 3100 but have settled on a load that does 3000 and will stay close to a 1/4" group. 75 gr. hollow points will shoot 1/2" more or less at 3400. The increase in velocity would be up to 200 fps over the standard .250 Savage. The case capacity is increased by about 12%. I believe that is the largest increases of all the improved cartridges Regrets, yep I've got 'em. It would be nice to have that cartridge in a better rifle. That old rifle has a rear locking bolt that limits the pressures that it can be loaded to without stretching the case and getting head separations. I've found that for the longest case life I use .243 brass that has the shoulder formed to have a fair bit of resistance to closing the bolt , resulting in no stretching of the case on the first firing. I don't think any other rifle would have issues.
    I like the one A.I. that I have well enough to consider a second. I've shot an Win. M70 30-06 from day One and think it's come to the end of the trail. I've always wanted a 6.5 something and a 6.5-06 A.I. seems about right:rolleyes: Cliff
     
  6. BountyHunter

    BountyHunter Writers Guild

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    You are asking one question that has a thousand answers and all are different.

    Best thing if you are serious is to buy PO Ackleys Handbook for Shooters and Reloaders Vol 1 and 2. Should be able to get them from www.sinclairintl.com or www.amazon.com

    He covers most of the improved cartridges, gives what works and does not, reloading data for powders existing at that time.

    Beware you will find about 10 versions of every AI cartridge and most dimensionally different. That means unless you know which reamer print your die mftr is using, off the shelf or standard factory AI dies will often not work. That means talking to the reamer mftrs (Dave Kiff at Pacific Tool and Gauge, Dave Manson at Manson Reamers, Clymer reamers, Henrickson Reamers etc) and find out which die mftr is using a specific AI reamer.

    You can go to any reamer mftr ( I use Dave Kiff at PTG) and get them to make a reamer for you (about $200 with go and no go guages) and then use Neil Jones to make a custom die set for any cartridge off the reamer print for $275-$300.

    BH
     
    Last edited: May 10, 2009
  7. TOM H

    TOM H Well-Known Member

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    Most Ackley chamber rifles if done right (headspace) you should be able to fire the parent case as most use that method to form cases. Problems happen when gunsmith doesn't set barrel back to rechamber to Ackley.

    Reloading for the Ackley is pretty simple. Start with known data for the parent caliber you will need to know how to measure CHE most likely you will go over max loads alot of that will depend on how chamber is cut/throated/twist and barrel length good example my 243AI with 80gr bullets @ 3700fps plus.

    I've got 8 Ackley chamber rifles and I've never purchased a reamer. If you did something the gunsmith doesn't have a reamer for you will have to buy the reamer if it's a caliber he may use then may split cost with you. Dies can cost extra but that alot of things that your gunsmith can answer.

    I've always started with new barrels as to rechamber and existing one as I much prefer to pick what may work better with gunsmith help.
     
  8. Slopeshunter

    Slopeshunter Well-Known Member

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    I had read on another board that AI chamberings generate less pressure than their parent cartridges. Is there any truth to this? Eventhough the AI has more powder in it is it more efficient due to the changes in the case dimensions??

    Can anybody speak to this for me?

    Thanks All!
     
  9. Bulldog

    Bulldog Member

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    Good point, I'm sure someday I'd run prolly a Grandslam in 4.75. Never know when a guy might poke an elk out around 300yds.

    I'd not AI the springfield. Just plain old 338-06 with Lyman peep sight.
     
  10. Jamie6.5

    Jamie6.5 Well-Known Member

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    Generally "no." They will however generate less bolt thrust. That is, the straighter case walls (less taper) are credited with gripping the chamber better and as a result, less rearward force is exerted on the bolt.
    As far as overall pressure goes, in the earlier cartridges, P.O. ran more pressure than factory loadings. The reduced bolt thrust supposedly gave him a larger safety window.
    Later loadings, such as the .257 Roberts+P made up for most of the gains of early Ackley chamberings. There are still advantages to most Ackley chamberings though. Especially the more unique ones.

    I have a chambering of the 6.5x.257 Roberts Ackley with the 40* shoulder that is my favorite. P.O. referred to the round as the .260AAR. AAR stands for all around rifle. It is one amazing round. .270 performance, 6-10 fewer grains of powder and .243 recoil. Very efficient, 150-200 FPS higher velocity than the .260 Rem, just as accurate and handles the really long 6.5 bullets better due to it's longer neck.

    Hope that helps.
     
  11. BountyHunter

    BountyHunter Writers Guild

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    The reason I said get your own reamer is simple, there are variations of almost every Ack Imp cartridge and they vary from 35 to 40 degree shoulders and different degrees of body taper.

    We know of at least 7-8 variations of the 300 Ack Imp and no one set of dies marked 300 Ack Imp will work with all of them with any expectation of accuracy and long case life. Now if your smith can furnish a reamer print, you can call that reamer mftr and find out if a die company uses the corresponding resize reamer for their dies. If so, then you can use the gunsmith reamer and that mftr dies.

    The key is matching the chamber reamer with the die reamer.

    BH
     
  12. TOM H

    TOM H Well-Known Member

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    I argree there can be lots of caliber called Ackely Imp/Ackley mag etc but most like myself we understand that there has to be a parent case. Why would anyone build a Ackley chamber rifle not know what the parent case is. Anyone can pull up this site and see the difference click on dies and see how many listed under 300 etc.

    You can get a reamer print really doesn't mean much if it's not headspaced right. Last time I check Neil still want a fired case
    http://www.neiljones.com/html/full_length_sizing_dies.html

    Don't want to get into a contest with you we just have different was of doing things. Let see I've got a 222AI, (2) 223AI,(2)6RemAI,(2) 22-250AI,243AI,280AI may do another 280AI. I did a 30 on the Nosler 280AI case,6x250AI,7x57AI,338 on a 270AI case plus others like 17 on 222AI case 7-08AI.

    I may be wrong but building a die from the chamber reamers may bump the shoulder back but doesn't FL size a case I assume that's one reason Neil want some fired cases here anothe site talks on FL die http://accurateshooter.wordpress.com/2007/07/26/hornady-offers-custom-dies/
     
    Last edited: May 10, 2009
  13. LewisH

    LewisH Well-Known Member

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    I have custom PD rifles for 22-250AI, 243AI, and 220 Weatherby Rocket, and, IMO, the extra steps required fire-forming (by whatever method), and then working up accuracy loads for the AI cases is just not worth the ballistic improvement over standard chamberings.

    If I had it to do all over again, I think I'd just stick with the standard chamberings.

    OTOH, maybe I'm just getting impatient and crotchety in my old age. :D
     
  14. BountyHunter

    BountyHunter Writers Guild

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    Tom

    Slight misunderstanding here. I am not saying try to build a FL sizing die from the chamber reamer. As you point out it cannot be done and yes Neil Jones still needs 5 cases fired 3X to build a set of dies. He is building two sets for me now. I can get a custom honed and matching die set without buying a resize reamer and still paying to chamber a set of dies by using Neil Jones.

    Yes, the gunsmith has to know how to properly headspace an AI chamber. I assumed that was a given.

    What I am saying is that many guys/smiths have "tweaked" the AI chamber reamers for AI cartridges to their specs but still call them AIs. That makes them different specs than what has been deemed original AIs but the reamer and barrel are still routinely marked XXX Ack Imp. My question is simple "How do you know if you have the original AI chamber or a modified AI chamber?"

    I used the 300 AI as a specific example with a known wide variance in different AI reamers and multiple AI die sets, most radically different in body taper and shoulder angles. Yes, you can even use multiple parent cases also in this chambering so some AIs can use multiple parent cases. Depending on which one you use effects the case OAL and trim length to make sure you do not end up with a big gap between the end of the case and end of chamber.

    You can match up chamber reamers from the maker with die mftrs with a phone call or email to make sure that you get an exact match.

    As many have pointed out, the AIs can be extremely efficient or extremely overbore and inefficient. PO Ackleys books run down the list.

    BH