375 DCM, 375/408imp

Discussion in 'Extreme Long Range Hunting & Shooting (ELR)' started by Kiwi Greg, Oct 8, 2012.

  1. Kiwi Greg

    Kiwi Greg Well-Known Member

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    I thought I would put this here as this cartridge is for ELR.

    I have been firing my 375 DCM, 375/408 Cheytac improved for a little while so I thought it was time I put some info up about it.
    The case was designed by a fellow Kiwi, Rocky Mountain, he also specified the barrel which is a 32" gain twist Bartlein 12-7.25.
    We had been waiting for these barrels for ages, they were supposed to be here before last Christmas....:rolleyes:
    She has an XLR HD Chassis, Barnard P-Chey action, 30 moa rail, Terminator muzzle brake, 5.5-22 x 56 NF NSX scope
    I haven't managed to shoot any great distance with her yet, the weather hasn't been helpful & the fact that my usual LR range is closed due to forestry operations....:rolleyes:
    I have decided to use the CE 425 pills that I asked Daniel at Cutting Edge to design & make for me in February this year, to use in the 375 Terminator & DCM.
    I will do more testing with the 375s & 400s but I'm very happy with how the 425s are going :)
    I haven't tested the BC of the 425 much yet but it did dial accurately out to 625 yards using 1.04 & I used 0.99 for the 400s out to 1700 yards in my 375 Terminator ( formerly Lil'Terminator)
    Here is a picture of her at the range.
    [​IMG]
    I have designed the T5 Terminator muzzle brake for it which works very well.
    [​IMG]
    I have tried a few powders in her & have decided that even though US869 gives me more velocity the temperature sensitivity, ES & accuracy aren't what I'm happy with, so I'm using ADI 2218/Hodgdon 50BMG.
    Here is a picture of a 338 Norma, 338 Lapua, 375 DCM, 425 Cutting Edge pill, 223 for size comparison.
    [​IMG]
    I am still only neck sizing my cases & they have been fired 4-5 times so far with very little head expansion :)
    Here is a group at 217 yards.
    [​IMG]
    Here is one with another grain of powder.
    [​IMG]
    As you can see she is showing heaps of potential, the ES is pretty good & should be able to be improved upon.
    We are happy with the speed & have been over 3100 but haven't settled on a load yet.
    More fine tuning to do to see what see likes at distance, good times :cool:
     
  2. Yrcan

    Yrcan Well-Known Member

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    I am very impressed with your gun. Congratulations :)

    I live in Norway, and I am planning a new long range gun. I currently shoot a 338 LM. I have shot it with good results out to 2000 meters.

    I have been looking at the 408 CT, but the police did not want to give me a permit for that caliber. But a 375 caliber gun, would be fine.

    Could you tell me more about this specific caliber, is it easy to find good bullets? Who makes the action? I know Barnard is shipping to Norway, maybe that's the way to go for me?

    Any info is highly appreciated.

    Please keep us posted on your project :)
     

  3. royinidaho

    royinidaho Writers Guild

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    Very nice!!!!

    Questions:

    What's the weight advantage of the stock/chassis you are using compared to a McMillan A5?

    What powder and how much of it are you using?

    I'm shooting a 375 Allen Mag and am limited to (so far) to 350 SMKs. But they do shoot very well @ 3200 MV

    Regards

    Roy
     
  4. paul2atlo8

    paul2atlo8 Well-Known Member

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    Are the gain twist barrels readly avaliable?
    Are the 375,400,425 pills also avaliable?
     
  5. Kiwi Greg

    Kiwi Greg Well-Known Member

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    The Barrels took ages to get as mentioned in the post, contact Bartilen about lead times, it may have been the exporting side of things that slowed them down...:rolleyes:

    The bullets should be easy enough to get contact Cutting Edge for info on distributors :)
     
  6. Kiwi Greg

    Kiwi Greg Well-Known Member

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    The XLR chasis is 2-3lbs heavier than my A5 with an alloy bedding block in it for the Barnard action.

    I'm using 50 BMG 150+ grains.

    I can't shoot the 350 SMKs in this rifle the exit twist will be too hard on them :D
     
  7. royinidaho

    royinidaho Writers Guild

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    Greg,

    Thanks for the answers.

    'nother question:

    I know nothing about those bullets but seem to gather that they are 'bore riders' with seating dependent upon the "ring".

    My rig is single shot. Except for extracting a loaded round, can I load and use those things?

    Oh! 'nother question: Mine is a 10 twist. Will at least the 375 grain offering work?
     
  8. paul2atlo8

    paul2atlo8 Well-Known Member

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    Called and talked to Bartlien,they are not making the .375 gain twist barrel(not enough demand)
     
    Last edited: Oct 11, 2012
  9. Kiwi Greg

    Kiwi Greg Well-Known Member

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    They should work fine in a single shot, they are long :D

    I would try some 350s & 375s to see which you & your rifle prefer :)
     
  10. Lovetohunt

    Lovetohunt Member

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    Hi, I have quite a few questions I'd like to ask you because my next gun will be an ultra long range rifle, probably a lot like yours. I already have a long range scope, a US Optics 5-25x 58 mm, I believe it's called the 5-25ER, and I like the XLR Chassis. Like you, I am looking to shoot something hotter than a standard 375 Cheytac and I like the ballistics you posted with the 425 CE bullets at 3100 fps and consistent velocities with the Hodgdon 50 BMG powder. I am trying to find someone in the US who chambers or will build a 375DCM or 375/408 Cheytac Improved. I assume they are the same cartridge? There is a 375 Viersco Magnum which is even higher velocities with the same weight bullet, but more concussion wave and shorter barrel life come with it, so I'd rather stick with what you got. Any idea on how far you could punch a hole in an engine block with that posted load? 1,000 plus yards I guess? :)
     
  11. royinidaho

    royinidaho Writers Guild

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    Lovetohunt,

    IIRC Dave and Kirby developed their 375 extreme magnum offerings at the same time but independently. Both came up with very nearly identical cartridges.

    Both are 375/408 CT Improved but there must be different levels of improvement.:)

    I shoot 350 SMKs @ 3250 w/142.5 grains of Retumbo out of a 30" 10 twist PacNor barrel. (Its the builders recommended load - which I've backed off a grain and a half just on general principles......)

    I'm not sure that all that velocity is necessary for taking game. However, to reach out to very ELR ranges ya need all ya can get.:D

    I doubt that, when shot sensibly, a persons life time isn't long enough to wear any of them out. Especially if ya start at my age.:D

    Your problems will be brass and barrel twist, I'm think'n.

    There seems to be a significant relationship between reamers and case manufacturers. If a reamer is designed based on one brand of brass and another brand is used there's gonna be a problem somewhere down the road.

    Concussion, now that's an experience. Especially for bystanders.:cool:
     
  12. Lovetohunt

    Lovetohunt Member

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    Hi Roy, any idea then on what reamer/brass brand to use on a 375/408 imp? Or rather, which reamers go with which brand of brass?
     
  13. Kiwi Greg

    Kiwi Greg Well-Known Member

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    The 375 Snipetac by Dave Veirs or Kirby Allens 375 AM are very similar to the 375 DCM.

    Dies & a reamer will be easier to get hold of.

    The barrel brand, length & twist have a major influence on performance.

    I prefer to use the fast twists to shoot the 425-450 CEB projectiles.

    Others prefer the slower twists & lighter projectiles.

    The heavy projectiles aren't cheap but their performance is incredible at ELR :)

    I haven't shot engine blocks, but IIRC a mate was putting holes in plates at 1000 recently, with 425s out of this rifle, apparently they were hardened.

    The 425 at 3100fps+ has an amazing amount of energy concentrated into a very small area with its SD.
     
  14. Lovetohunt

    Lovetohunt Member

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    Hi Greg,

    Thanks for the reply. Dave Viersco told me the 375 Snipetac shoots a 375 grain bullet at 3150 fps. I'd like to shoot the 425 grain CE's because of that incredibly high SD, and I'd like to shoot them at 3100+ fps. 32 and 34 inch barrels seem to be popular, and I hear of some people using 38 inch barrels. Do you prefer a gain twist for the 425's, or straight twist, and what twist rates do you think work the best for the bigger pills??