338 Kahn vs 338 Lapua mag IMP

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Jimm, Dec 16, 2005.

  1. Jimm

    Jimm Writers Guild

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    Pros and cons please ,

    I like the idea of Lapua brass . What brass best choices for the Kahn ? Any comparisons would be great . Thanks a mill as I'm plotting to build the 338 lapua mag IMP unless you guys educate me otherwise /ubbthreads/images/graemlins/grin.gif, Jim
     

  2. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Jimm,

    If your shooting a 30" barreled rifle, with a 300 gr ULD or VLD bullet, from what I have seen on average, the 338 Lapua Imp will be in the 2825 fps range with top loads. The 338 Kahn will be in the mid 2900 fps range and at times some rifles will play with 3000 fps.

    There are always variations, some rifles are faster, some are slower but this is about the average I have seen.

    Brass to use for the Kahn is Wby 338-378 brass. It is made by Norma and is good quality brass as well. Maybe not quite up to the specs of the Lapua hulls but still about as good as you can get. I will say Lapua cases are harder and handle very top end pressures a bit better then the Norma brass.

    Kirby Allen(50)

    Kirby Allen(50)
     

  3. Jimm

    Jimm Writers Guild

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    Kirby,

    Thanks for your input, it is much appreciated !It seems that the difference in velocity is more than outweighed by the brass difference.
    You mentioned a 30 " bbl, would a 32" give enough add'l velocity to be worthwhile? Realizing of course that the best accuracy node may be less than the max velo that can be achieved .

    Thanks again , Jim
     
  4. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Jimm,

    I really recommend limiting barrel length to 30" unless you have a dedicated Heavy rifle in mind. The reason is that past 30" of barrel length, barrel mass really becomes critical in maintaining proper barrel rigidity for extreme accuracy.

    In the 338 bore size, 2" of added barrel are really not that advantagous to velocity gains. You will see around 35 fps gained with the Lapua Imp and around 45 fps gained with the Kahn from 30" to 32" of barrel length.

    The reason is because the 338 bore is relatively efficent even with these case capacities.

    If someone wants a heavy rifle then I say go with at least a 34" barrel or even a 36" pipe but for a medium weight rifle I like to recommend a 30" barrel length and a #7 contour at very minimum for a 300 gr ULD bullet at these velocities.

    Actually prefer a #8 contour to be honest but a #7 will work if weight is a concern.

    For a heavy rifle, the use of a V-Block system greatly stabilizes the barrel, even if it is a 40" barrel. For a V-Block I like to use a V-Block that is at least 30% the length of the barrel.

    For example, if you use a 36" barrel, 30% of that length would be 10.8". I would use an 11" V-Block.

    Using this length of V-Block, you would only have 25" of unsupported barrel which translates into a VERY STIFF BARREL!!

    It just depends on the type of rifle you are looking to have built and what you want to use it for as far as barrel length is concerned.

    Kirby Allen(50)
     
  5. alremkin

    alremkin Well-Known Member

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    How about the Weatherby Accumark bedding system is it possible to adapt it to a longer barrel a 30" or 32" in #8 contour in the 338 Kahn? Or would the whole barrel and bedding system have to be changed? I'm not fond of this zolatone stock on my Accumark, but I'm wondering how far one would have to go to make a reasonable rifle to be carried in the bush with the rifle weighing &lt; 11lbs without scope? Right now I'm just curious as I just got my Mark IV rings so I can mount my scope and start shooting. It's been a long journey for this rifle and I re-joined the range last weekend and went to their Christmas party.

    As well I received my grizzly/buffalo bullets from Richard Friday, 300-325 gr tappered jacket bonded core mag tip flat base, quite a mounthful. And I've taslked to a Buffalo rancher north of Edmonton who wants to thin his herd. I may be going there in late January or February. It's not really a hunt in that he will tell me where they are, but the price is right $500/buffalo and I didn't get to go hunting this year... /ubbthreads/images/graemlins/frown.gif
     
  6. Boss Hoss

    Boss Hoss Well-Known Member

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    I don't have any pics but SG&amp;Y finished my 338 Lapua Ack Imp about a month ago and I have fire formed the brass and have some loaded to try but have not gotten out to the ranch to shoot it yet. Mine started as a 30-378 and now has a Broughton tube with the SG&amp;Y brake which takes all of the punch out of the rifle! I did not even have to use the PAST when braking in the barrel and fire forming. I ordered the reamer from Dave Kiff at PT&amp;D so if you want to have one built Speedy has the reamer and I have never gotten a rifle from Speedy and Stick yet that would not shoot lights out! /ubbthreads/images/graemlins/cool.gif
     
  7. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Alremkin,

    I place the Wby MkV in the same class as all the other factory receivers when recommending barrel length and mass. Again, I would not recommend over a 30" barrel without a special bedding system being used.

    Those 325 gr FB bullets are impressive for sure. I picked up a few when I was up visiting Richard. Will be trying them in my 338 Kahn and 338 AM(when I get that BAT receiver!!)

    One thing to rememeber. Anytime you increase bullet weight, or velocity or bullet length, the barrel will be strained more as the bullet passes through the bore.

    I still say 30" is the longest I could recommend to ensure good accuracy with bullets in these weight and length ranges.

    The Buffalo cull should be a good time. LOTS of bullet testing data on that one!!

    Let us know how they perform.

    Kirby Allen(50)
     
  8. Jimm

    Jimm Writers Guild

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    Kirby,

    What is the cost of a BAT action ?

    Jim
     
  9. Black Diamond 408

    Black Diamond 408 Well-Known Member

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    Jimm

    The Bat Actions run from 1100.00 on up to 1300.00
    website web page
     
  10. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Yes What BD408 said!!

    Kirby Allen (50)
     
  11. uncleB

    uncleB Well-Known Member

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    jimm,
    this is what the 338Lapua Mag Imp.(MOAG)is capable of,the 338Kahn is capable of the same. the Lapua brass is harder to neck-turn but the Norma brass is still First-Rate. the biggest difference is that the Lapua does not have the Hoola-Hoop around the ankles like the Wby. case
    [​IMG]


    [​IMG]
    UB
     
  12. Jimm

    Jimm Writers Guild

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    Thanks UncleB,

    Btw , congratulations again for the L.S.O.T.Y. award. I reckon you all had a blast getting there.I know its on here somewhere but I have bad enough eyes as it is without reading through a gazillion posts to find out, so , please spec that rig again if you don't mind .

    Happy, merry , joyful celebration of Christs birth to you all.

    Jim B.
     
  13. pc

    pc Well-Known Member

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    Uncle B what is that awsome rifle have for an action my friend and I want to build something like that oned day............can you give me all the specs if thats alright ?
     
  14. uncleB

    uncleB Well-Known Member

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    jim &amp;pc,
    It is a 338 Lapua Imp.36" Krieger 1.45" barrel,8.5" BAT action Jewell Trigger, McMillen hbr50 stock with a Shehane barrel block,BAT also made the 20moa base and it has 20moa ring's as well. topped off with a premier boosted Leupold 14.5x35 scope.
    UB