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Thread: 260AI versus 260?

  1. #1
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    260AI versus 260?

    I have just ordered an 6.5 barrel and am leaning towards having it chambered in 260 or 260AI. This will be a hunting rifle, probably on a Model Seven or 700 action. Max barrel length will be 26".
    I'd appreciate any thought or experience on the gain going to a 260AI comapred to the standard 260.
    Thanks
    Jim

  2. #2
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    I see no gain to be had.

    Like the .243AI people CLAIM great gains but in fact they just run the pressure higher on the AI'd cases.

    My vote is for the plain-jane version except that the AI looks cooler.

    The real downside of the AI'd rounds is that they always produce excess gapspace which can be a real pita. The only way to avoid this is to have two reamers and a dedicated FF barrel, a REAL pita.

    Were it me, I'd order my reamer to be .005 over the virginal brass at the rear and leave the rest of the case alone. I'd also order my go-gauge .003 or more UNDER-sized so that the gunsmith can't screw up your chamber. Re-set every shoulder on your brass for crush-fit and have at it.


    opinionsby

    al

  3. #3
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    Thanks Al,
    I'll file that away and use it for my decision process. Actaully I'm copying it to a Word file where I'll save all the info and opinions I get.
    I am just getting started and as the barrel is 4 to 6 monthss out there, I have time ruminate on it!
    Jim

  4. #4
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    I like Mine

    142 smk @ 2980 with a bartlain 1-8.5 with 3100 5-8 reloads per piece of ww 7-08 brass also really like the 139 scenars

  5. #5
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    I can not comment on the 260 - never owned or shot one, but I do own a 260AI barrel for my Encore. If you have any 260 data to compare my numbers to that will help in your decision process.
    The barrel is 27" 1/8 twist. H2O capacity is 57.5 gr. Here are some of the loads I tested. 142 gr Sierra Match Kings, Varget 42.0 gr mv = 2980. Lapua 123 gr Varget 41.2 = 2872. H4350 46.6gr got them going 3140. I never ran into any pressure problems, so probably could run them hotter.
    Is that much better than a 260? Don't know.
    There are other advantages than just speed to the AI. Others can comment on those.
    There are also disadvantages. Dies cost a little more. Process of fireforming - which really isn't a disadvantage if you like shooting. If you go on a hunting trip and forget your rounds- chances are you won't find any "box" cartridges at the local hunting store.
    Deer sized game are not going to know the difference if they got shot by a 260 or a 260AI. In the end, it will be your choice - get as much info as you can - make the decision - and don't look back, it will be a sweet medium sized game rifle no matter which way you choose.

    Stanley

    Stanley
    Last edited by Apollo; 04-03-2009 at 08:01 AM. Reason: info

  6. #6
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    Quote Originally Posted by Apollo View Post
    I can not comment on the 260 - never owned or shot one, but I do own a 260AI barrel for my Encore. If you have any 260 data to compare my numbers to that will help in your decision process.
    The barrel is 27" 1/8 twist. H2O capacity is 57.5 gr. Here are some of the loads I tested. 142 gr Sierra Match Kings, Varget 42.0 gr mv = 2980. Lapua 123 gr Varget 41.2 = 2872. H4350 46.6gr got them going 3140. I never ran into any pressure problems, so probably could run them hotter.
    Is that much better than a 260? Don't know.
    There are other advantages than just speed to the AI. Others can comment on those.
    There are also disadvantages. Dies cost a little more. Process of fireforming - which really isn't a disadvantage if you like shooting. If you go on a hunting trip and forget your rounds- chances are you won't find any "box" cartridges at the local hunting store.
    Deer sized game are not going to know the difference if they got shot by a 260 or a 260AI. In the end, it will be your choice - get as much info as you can - make the decision - and don't look back, it will be a sweet medium sized game rifle no matter which way you choose.

    Stanley

    Stanley


    A few things here, re this statement... "There are other advantages than just speed to the AI. Others can comment on those." I will comment on this, IMO there are no advantage. If there are, NAME THEM..... (And please, if you're going to contend that brass "flows less" then support the claim)


    And this.... "chances are you won't find any "box" cartridges at the local hunting store."...... what exactly does THIS mean?? AI'd rounds BY DESIGN will shoot factory rounds. If you can't find off the shelf stuff then your gun is set up whack.

    al

  7. #7
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    Al, does any Ackley Improved make sense?

    Quote Originally Posted by alinwa View Post
    A few things here, re this statement... "There are other advantages than just speed to the AI. Others can comment on those." I will comment on this, IMO there are no advantage. If there are, NAME THEM..... (And please, if you're going to contend that brass "flows less" then support the claim)


    And this.... "chances are you won't find any "box" cartridges at the local hunting store."...... what exactly does THIS mean?? AI'd rounds BY DESIGN will shoot factory rounds. If you can't find off the shelf stuff then your gun is set up whack.

    al
    I'm contemplating a .30-06 AI, and wondering if you (or others) have any comments as to whether that's worthwhile over a standard .30-06. One of the things I like about the AI concept is that I could (and would, for fire-forming at least) shoot factory ammo through it. And per Jerry Tierney, sometimes SAAMI loads shoot very well indeed through an AI chamber, but that's another topic.

    I prefer to KISS, so I'm contemplating the real advantage of an Ackley Improved. Intended application would be shooting to 1,000y, and perhaps to 1,200y (just because I never have before), mostly at paper targets, but who knows someday...

  8. #8
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    I've heard that you don't have to trim your cases as much - but, like you said, I don't have any proof of this - that is why I didn't post that the first time. Other advantages would be; the uniqueness of having an Ackley, the time spent on a project that not many others have. Are those advantages that will show up on paper or terminal effects? Nope, but they are still advantages of owning an Ackley.

    If you go to Scheels - you probably won't find any 260 AI rounds. Will you find some 260? Maybe and yes - they will still fire in a 260AI chamber. But if you plan on forgetting your hunting rounds - why do the Ackley? That is why I listed it as a disadvantage.

    Al, If you want to argue - why not just come visit with my wife?
    Last edited by Apollo; 04-03-2009 at 11:55 AM.

  9. #9
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    Quote Originally Posted by Bill Ohio View Post
    I'm contemplating a .30-06 AI, and wondering if you (or others) have any comments as to whether that's worthwhile over a standard .30-06. One of the things I like about the AI concept is that I could (and would, for fire-forming at least) shoot factory ammo through it. And per Jerry Tierney, sometimes SAAMI loads shoot very well indeed through an AI chamber, but that's another topic.

    I prefer to KISS, so I'm contemplating the real advantage of an Ackley Improved. Intended application would be shooting to 1,000y, and perhaps to 1,200y (just because I never have before), mostly at paper targets, but who knows someday...

    Bill, I've shot a herd of Ackleys..... when I was in gunsmithing school they were de rigeur. One of the few that I currently advocate is the 30-06AI, a definite improvement over the venerable 30-06. Many folks don't realize that 30-06 rounds will actually collapse at the shoulder from firing pin impact. The firing pin CAN and WILL change the headspace on unfired 30-06 brass. Fired and hardened brass will withstand the force but Ackleyfying will hold 100%. Also the problem of pullback of the neck is minimized by the short shoulder. IMO a properly headspace 30-06 Ackley will be .006-.012 SHORT of a "go-gauge." A monstrous jamfit is wicked hoovis. When I set up an -06AI I set the chamber to be a solid jam on several brands of factory loads. TIGHTER is better, you can quite easily gain jam on a 30-06 case due to the minimal and shallow shoulder.




    Apollo.....

    Whatever man. This is BRC not "Unfounded Guesses I Got From A Magazine," Central. It's not an argument until you present some sort of rational reasoning/discussion, preferably based on experience.

    al

  10. #10
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    Hey Guys,
    Please don't turn this thread into an argument. I was just asking for opinions and experiences. I'll just take what gets posted and think about as I make my decision.
    I kind of like what Appolo wrote:
    "In the end, it will be your choice - get as much info as you can - make the decision - and don't look back, it will be a sweet medium sized game rifle no matter which way you choose."

    It will in the end it usually comes down to personal preference. There sure isn't a lot of balck and white choices in these matters. I am still curious about possible velocity and case capcity gains with the 260AI.

    I do appreciate Al's insights for sure. I wish I knew a quater of what you seem to know about gunsmithing!

    Redrock,
    Is that a 260AI that you are getting 2900+'/sec with a 142 gr bullets? And what length barrel?

    Appolo,
    Is the 57.5 gr. water capacity measured to the base of the neck or a full case.
    Thanks to all.
    Jim

  11. #11
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    Barrel Length

    Mine is a 260 AI and the barrel length is 26"

    Reason for owning, cause thats what I wanted.

  12. #12
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    Jim,

    That number was a full case. Might be off a little based on the meniscus of the water, but was just an average of 5 trials done about 2 years ago when I went through that ackley project. Hope you find your needed information, let us know what you decide.

    Stanley

  13. #13
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    Thanks Redrock,
    The barrel I am ordering is a light sporter contour that is tweaked so that I can have a length of 26" and have the same muzzle diameter as the contour would normally have at 22". I had one done like this for my 7-08 and it worked out really well, fairly light for carrying purposed but not whippy like a featherweight. I had the 7-08 cut at about 23", but the 6.5 will probably start out at 26". That 2900'/sec velocity would be a good reason to stick to 26"!
    Getting it because you wanted it sound like a good reason.
    I am in the middle of having a 6mmBR rifle put together. It started out with an inquiry about a stock a guy was selling. As we e-mails back and further I got to buying a barrel and barrel block along with the stock. My buddies have asked me what the heck do I want with a 6mmBR as there isn't any competion for something like that up here? The reason, I have been wanting to try a super accurate cartridge like that for some time, the price was right, and it sounds like fun!

    Stanely,
    Do you remember what brand of brass it was that you measured the H20 in?

    Have either of you tried Hornady 140 A-Max's? Hornady recommends a minimum twist of 1:7.5" I e-mailed them and they said that 1:8" would be border-line and whether it would stabilize the 140 A-Max would depend a lot on the velocity. I assume faster is better within reason.

    It is going to be months before I get the barrel and I can't say that any decision will be 100% final until the barrel is here and I hand it to the gunsmith!
    Take Care
    Jim

  14. #14
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    Here is some good reading

    http://www.the-long-family.com/260AI.htm



    http://www.6mmbr.com/gunweek046.html

    These two guys have done alot of the leg work your looking for, is it worth it? Doesn't sound like it is to Alinwa, but it was for these two guys, myself and Apollo, you'll have to make up your own decision.

    I'm a tinkerer and like messing with things, if you just want to load and shoot, go with the 123 Sierra Match Kings with a .260 rem and have a blast.

    Your in the fun stages of your rifle build, keep it that way.

  15. #15
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    Jim,

    The cases I choose to use were Remington.
    Yes, I shot some 140 A-max's, but they didn't group near as good (in my barrel) as the Sierra's and Lapua's so I focused my efforts on the 123 Sierra and Lapua and the 143 Sierra's. I have the load data at my work. I can get that for you, if you like, tomorrow.

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