.280 AI vs .284 Winchester AI...

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by BlackKnight755, Dec 16, 2010.

  1. BlackKnight755

    BlackKnight755 Well-Known Member

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    I want to build a new long range rifle and I am looking at the .280 Remington ackley improved or a .284 Winchester ackley improved. I need to know if the .284 has/can be made? Also which one has the largest case capacity? If I am reading correctly, both are .284 and the BC is out of this world for that cal. Berger states .617 and .659 for the VLD's that I want to use. If anyone cares to, please share what ballistics that I can expect from both cartridges. I will be shooting a 32" Broughton 5C barrel so I should get some added FPS in the long barrel. I intend to shoot 1000 yards and farther with the new rifle. Any help will be greatly appreciated. BK
     
  2. AZShooter

    AZShooter Well-Known Member

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    You didn't mention the action length. SA dictates you use the 284.


    Is this rifle going to be a repeater or single shot? I am asking because the 168 and 180 VLDs are quite long. If it is going to be a single shot it is no big deal. Otherwise the 280 AI may require a custom action to accomodate the length and still feed from the magazine. For optimal performance with either case you should consider a custom reamer.


    There is an improved version of the 284 win called the 284 Shehane but technically it shouldn't be called an Ackley Improved. Bill Shehane designed the case's body-taper a bit larger about .010", but didn't change the shoulder angle from the original 35 degrees. It is supposed to add around 3.35 grains of powder. I have a friend who made one for long range shooting and said it wasn't worth the effort. FYI just by using RL-17 you can gain more velocity over the usual H4831 and 4350s.

    As for the 280 AI I cannot tell you as much as I am not familiar with it. Perhaps someone else can add to this thread.

    Here is a link for some reading about the various short action 7mms:

    7mm Cartridge Guide
     

  3. BlackKnight755

    BlackKnight755 Well-Known Member

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    Thanks for the input AZShooter,

    I intend to use a long action that I have. I will be using the rifle as a single shot by installing a removable follower.

    I have read about the .284 Shehane and when I go to the expense, I will have a reamer made in the Ackley Improved. I will have custom dies made also.

    I have a .280 AI in a hunting rifle setting that does real well. It has a much shorter barrel, 26", than I want for my target rifle but it still holds up at 1000 yards. I think that one reason that I am interested in the .284 Win. AI is because of the performance that I have seen in the .280. I am thinking that with the possibility of more case capacity, thus comes more velocity and being able to capitalize on the high BC of the .284 bullets.

    Can someone tell me the case capacities on both cartridges. If you only know one please post as someone else may know the other one.

    Thanks again and keep the posts/comments coming! BK
     
  4. Trickymissfit

    Trickymissfit Well-Known Member

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    first of all there is no such thing as a .284AI, but it needed to be done. Ackley almost always used .010" taper per inch with a 40 degree shoulder. You already have a 35 degree shoulder, and a similar amount of taper. The best thing that could happen to the case is to shove the shoulder back about .06" to give the bullet something better to seat in. Plus it totally keeps the flame path inside the neck to promote a better barrel life. I think you'd be better served with the .280AI if your planning on the use of very long bullets. Of course you could also use a 7x57AI and get virtually the same results as with the .280AI. These rounds will fit the magazine better also

    Also note that a 26" barrel is about the max length you'll ever need in the 30-06 case. You'd probably be just fine with a 24" barrel, and group a little more consistently.
    gary
     
    Last edited: Dec 17, 2010
  5. BlackKnight755

    BlackKnight755 Well-Known Member

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    Gary,

    Thanks for the reply and suggestions. Do you not think that the longer barrel, 32" would be beneficial when it comes to more FPS? I have a 6.5x284 with a 32" broughton 5C on it and I shoot through the chronny almost 100 FPS faster than my friend and his shorter hunting barrel. His is a 24" broughton 5C. We shot the same exact load for the test, and I KNOW that mine is more accurate than his especially at anything over 600 yards. Also OAL is not an issue as I will be single feeding the ammo, it will never see the inside of a magazine.

    Thanks again for the reply, BK
     
  6. BlackKnight755

    BlackKnight755 Well-Known Member

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    ... Ok, It has been said that there is no such animal as a .284 Ackley Improved. My next question is, can one be made and if so who could I get in touch with to see what I would need to do next? I know that I'm not inventing the wheel and I am sure and positive that I'm not the first on to think about the .284 as an Ackley Improved cartidge right?
     
  7. AZShooter

    AZShooter Well-Known Member

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    Anything can be done all it takes is money. Talk to Dave Kiff at Pacific Tool and Gauge he'll make you that custom reamer. I think you are going to encounter some serious costs for a tiny bit more velocity. I'd opt for a 32" barrel and a standard 284, which is going to give you good performance or go with a larger case like the 7 WSM. All you would have to do is open up the bolt face. No custom reamers or fireforming.



    Read what these guys did with the standard 284:

    Record-Setting .284 Win F-Classer

    NBRSA 1K Winner Jerry Tierney

    ------

    A couple of 7 WSMs

    Vince B's 7mm WSM Record-Breaker (7 Win Short Mag)

    7mm WSM -- High-Country Hunter
     
  8. Trickymissfit

    Trickymissfit Well-Known Member

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    I know I'll be staked over an anthill over this comment, but I'm also pretty thick skined!

    * in a .284 sized case there is absolutly no need ever for a 32" barrel unless you are think the muzzel being 6" closer to the target will help. You only need enough barrel length to burn the existing powder in the case, and anything more creates other problems (harmonics), and that's using 8700 powder. On the other hand you can use a slightly faster powder burn and get virtually the same velocity.

    * your testing is flawed when compairing two different guns and barrels even if they are of the same make. No two barrels shoot exactly the same. The only true test would be to cut the barrel a couple inches at a time till you reached a point in change that was significant.t would be interesting to do a case compairison between five once fired cases from each gun ( cases from the exact same lot number & die set). Just the throat alone can cause over a hundred feet per second difference.

    Secondly the shorter barrel shooting 100 fps slower could well be from the load selection or even from the actual bore in the barrel. A load built for the 24" barrel will show no real gain in a 32" barrel, and may even end up slower. Build the rounds up using AA3100 or 4350 (perhaps MagPro?), and take another look see.

    * Another major factor in accurate shooting is barrel harmonics. Kind of a black art, and often ignored way too much. In a high powered rifle you can only do so much to resolve the issue without going to a tuner. This is why heavy barrels tend to be a little more consistent and much more forgiving in our errors. Why? The rigidity of the barrel tends to fight the harmonics created by ignition, as well as the torque created by the bullet as it goes thru the barrel. The stiffer the barrel the better the groups as a rule. But there's some more to this. Lilja has stated that a typical #7 contour barrel 21" long will be 2.75 times stiffer than the same barrel 26" long (in otherwords the longer barrel is moving all over the place). It also becomes a tuning fork; thus creating bad harmonics. A 24" barrel compaired to a 32" barrel will probably be at least 2.5 times stiffer if not 4 times stiffer.

    Not be mean, but pointing out a few facts
    gary
     
  9. Trickymissfit

    Trickymissfit Well-Known Member

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    except for the shoulder angle, the case fits all of Ackley's specs. He would have probably not called it an improved case because he would have increased the neck length to about .31" by pushing the shoulder back a little bit. For the case to be an improved case you have to be able to chamber and fire a factory case in the chamber. All I'm saying is that by changing the shoulder angle to 40 degrees you will not see much improvment in velocity, but have a slightly better flame path (very slight). But you push the shoulder back .06 to .093" with the 40 degree shoulder, and you have a different ball game. (also helps with case shrinkage issues during fire forming) You will see little if any loss in velocity, but increase case & barrel life signifcantly (6.5/.284's often eat barrels in 600 shots). Ackley didn't always improve a case to gain velocity, and often did it to increase case or barrel life. He was just way ahead of his time.

    this weekend I'll make a CAD drawing of the two cases. One with the 40 degree shoulder and the other with the standard 35 degree shoulder. Yet keep the shoulder deminsion in the same place to see how the neck comes out. May do a third one with a .062" shoulder setback as well. Guys I know that are shooting 6/.284's (a real barrel eater) are pushing the shoulder back .100", and seeing no loss in velocity while the barrels lasts much longer. There are a couple I know that have gone so far as to push it back .150" (also shortening the neck a little bit), and are seeing about a 75 fps loss in velocity with much tighter groups. These barrels tell me that Ackley's vision of overbore was dead right.
    gary
     
  10. svendi

    svendi New Member

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    I also have a question for you guru's out there....I have a .284 Win with a mohawk 600 action and I love it to death, it seems like it is incapable of a miss when its time to dorp a critter. However, I was hoping to make it a 1000 yrd hunting rifle by adding a new HS Prescion stock and a Huskemaw 5-20. I was wondering if this in your opinion would be a waste of money or would I be happy with the results? I'm pretty sure I'll love the gun one way or another, but I'm not sure if the .284 has the juice to drop an elk at 1000yrds. I understand its all about shot placement and terminal performance, but is working up a load and putting $2000 in stock and optics worth it or should I step it up into the .30's? Personally, I think it should be ok, but I like to pick as many brains as I can before spending my money. Anyway, fire away and let me know what you guys who have been in the game longer think. thanks.

    gun)
     
  11. Lapua guy

    Lapua guy Well-Known Member

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    The stock does nothing for accuracy. If you bed the action to the stock, then you will increase accuracy, if it is done right. So will a custom barrel. A rifle will only shoot what it is capable of shooting. A scope may make it so you can see your target better and have the accurate amount of bullet drop and windage holdover, like the Husky, or G7, or GBP allows, but it won't make a rifle shoot better than it already is capable of shooting. That depends on the bedding job, the truing of the action, the barrel, the load, and even the quality of brass to an extent.

    There is a lot more to it than just buying a tactical stock and putting good glass on the rifle.

    If your rifle already shoots in the 5s (1/2 MOA at 100 yards), then I wouldn't mess with it, unless it is due for a barrel change. Then I would have it bedded and a custom barrel put on it. If it doesn't shoot that tight, then I would do the same thing to get it there. If you are going to shoot game at 1000 yards, you want an accurate gun.

    As far as the capabilites of the 284 at 1000 yards, I would say it could definitely kill an elk, I just don't think it is ideal. Personally at that range and that size of animal, I would look at something that shoots a 300 gr 338 projectile. Great BCs. I use a 338 Lapua and started using a 338 Edge recently, but you wouldn't even have to go that big if you didn't want too. A 300 Win, or 7mm Rem Mag would work too if you didn't want to go to the big 338s.

    Sounds like you are passionate about going LR. It is great to shoot further and further as you progress in experience.
     
    Last edited: Mar 8, 2011
  12. elkaholic

    elkaholic Well-Known Member

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    It's probably already been mentioned but you wouldn't gain much by A.I. ing the .284. The .280A.I. will give you more case capacity, and as per our earlier conversation, the .280 Sherman is better yet.......Rich:D
     
  13. LRangepro

    LRangepro Member

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    A bit late to this post, but I built a 280 AI in 08 or 09 for tactical matches, I've shot both Berger 168s and 180s with GREAT results in a 27 inch Krieger, 1/9 twist. I shoot it at about 3060 with 168s, no pressure signs and about 1 inch groups at 500 yards. (.896 my best averages around 1 -1.2) I can get about 3000 with the 180s as well but its starting to look like max at that point. Standard reamer was used, bullets seated to reach lands and still fit in 700 LA BDL mag and feed great. Super sonic to a mile and about 22 MOA at 1000 yards. I cant say enough about this for long range. Most people never consider heavy bullets with a 280...but they should! Also case life seems forever with just a kiss on the shoulder, less than a thou. and never need to trim after first time.