375 cal barrel twist and projectiles?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by the claw, Jun 12, 2010.

  1. the claw

    the claw Member

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    Hi all,

    I've been a bit of a lurker on here for years now, thought it was time to come out of the closet and ask a question...!

    I am thinking of building a 375 Cheytac, or a varient of this such as an Allen Magnum. My question is, what is the current thinking on the correct barrel twist for available hunting projectiles? What is out there as viable hunting projectiles for the 375 other than the 350gr SMK? (high BC projectiles that is).

    Those of you that have a 375 CT, AM, or similar, what weight is your rifle? How is (percieved) recoil with your rifle? I am trying to decide what weight to aim to build, my current thinking is 15-18lb bare, is this too light? I will be using a single shot Barnard action, and probably a 32 inch barrel.

    Any other considerations, pearls of wisdom would be appreciated.

    Thanks in advance.
     
  2. royinidaho

    royinidaho Well-Known Member

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    I have a build in progress, hopefully nearing completion, in one of those cartridges.

    BBL is a Pac Nor 31" 10 twist.

    Availability of bullets, such as the 350 SMK, is a consideration.
    I happen to have a sufficient supply of the 350s.

    Since ordering the 375 I'm beginning to see that the 375 in an improved chey tac case may be a little bit behind the 338 cal in the same case. A 375 super hooty magnum just sounds niftier.....

    Though mine will be heavier than the 15 pounds you mention, 15 pounds isn't too light, I don't think. I would have gone the 16 pound route, Idaho legal limit for big game shooting, except I chose to not deal with the additional expense and time involved. I purchased parts and pieces from members here, which were immediately available. Which as it turned out didn't make much of a difference in delivery time.

    Good luck
     
  3. Varminator 911

    Varminator 911 Well-Known Member

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    Rocky Mountain Bullets has a 370 gn rebated boattail aluminum tip. G1 BC=0.926, G7 BC=0.451. Recommended twist at 2800 fps= 1:11. Cost $215/100.

    They have 338s from 225 to 325 gn. The 300 and 325 have better BC than the above 375 bullet. I'm still thinking a 338.
     
    Last edited: Jun 12, 2010
  4. Chas1

    Chas1 Well-Known Member

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    Welcome, glad to have you here. Lots of good folks and lots of good info. Enjoy.
     
  5. the claw

    the claw Member

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    Thanks for the welcome Chas1.

    It seems that there is a much better choice of 338 cal projectiles. I haven't dismissed it as a alternative to the 375. The main attraction of the 375 (for me) is the increase in barrel life over the 338, but in reality, barrels are cheap, and if I was to start with a 338, I could always step up to the 375 if and when a better choice of projectiles is available...

    Make sense?...
     
  6. Chas1

    Chas1 Well-Known Member

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    The claw, I like your thinking and I think your right. When one considers the total cost of a build, barrels are cheap. As an example I'm currently having a custom built which will run 7-8k when all is said and done and the barrels about 500 of that. So in the scheme of things I think your right. You could go 338 until bullets were offered to your liking plus in the meantime you might get having and shooting a 338 out of your system so to speak. Keep us posted on what you finally decide.
     
  7. kellyzier

    kellyzier Well-Known Member

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    You came to the right place for all your questions...There are alot of guys here that can help you and there are some gunsmiths as well that have a ton of knowledge about these calibers.

    Before I started my build, I researched it for about 6 months. I was torn between the 338 and the 375. From the get go, both of these calibers can burn barrels. I ended up going with the 375 snipe tac that was the brain child of Dave Viers at Black Diamond.

    After speaking with Kirby Allan (the author of the Allen Mag's), I found out that the 338's were eating up barrels and that his 375's ate them as well, but at a slower rate. And ballistically, Kirby believes that they are basically twin brothers.

    I spoke with a few other gunsmiths that pretty much confirmed Kirby's communication to me.

    The real challenge has been the bullets for the 375, but more recently, we are seeing a lot of momentum from the various bullet makers for the 375, making this a very interesting cartridge.

    Even now, trying to marry your barrel twist to bullet type can be challenging. There is so much new development going on, its hard to keep up.

    Personally I have ordered all of my parts and everything is almost ready to go except for the actual cutting of the barrel. My barrel maker has two barrels for me ready to cut, but I have held him off waiting for results from some range tests.

    My first barrel will be cut to a 1-10 twist so I can test various bullets like the lehighs, preditors and GS and ZA. My second barrel will probably be a 1-8.5 for some of the longer solids that folks are shooting.

    And lastly, as I have been pulling in parts for the 375 snipe tac, Dave Viers has been putting together a totally new caliber. It's the new 375 Vierso Mag. This new caliber will be the grand daddy of all 375's. He's hoping to design it in a 1-8 twist to shoot some of the longer 400 ish grain solids like the ZA's and GS's.

    If I had known about Dave's VM, I would have built that caliber instead of my snipe tac, but oh well. As I said, lots going on in bullet development and if you wish to jump in now, it would be good to ask a ton of quesitons and take a lot of notes.

    cheers
    zman
     
  8. LR3

    LR3 Well-Known Member

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    Claw, I have both a 375 Dave Viers SnipeTac and a 375 AM. They are both great rifles and the question is what your ultimate plan is. The Snipe tac is a single shot and lighter and I can hike with it - shoots very well and on Tuesday I was with Tom Sarver and it grouped 6" at 1000yds althoug 4 were into a 2" group. On elk this is a great rifle and leaves a 5" exit hole. The 375 AM is heavier and has a magazine and is more for bipod / rest shooting and is faster but heavier. One is a Krieger the other a McGowan barrel: one 10 and the other 12 twist. The 350 SMKs are great although I have some GS rounds also. Jamison has the SMKs
     
  9. kellyzier

    kellyzier Well-Known Member

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    LR3, this info is most helpful...I am building a 375 snipe tac with a 1-10 twist.

    Is your Snipe Tac a 1--10 twist??

    And what loads are you using for the SMK's and what speeds with the snipe tac? powder, dist fm the lands, primer, etc......

    Thanks
    kelly
     
  10. groper

    groper Well-Known Member

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    Heres mine kelly.... 1:10 twist

    it should be able to shoot the following;
    350gr SMK
    355gr GSCustom SP
    350gr Predator projectiles
    370gr Rocky mountain Al tippped
    350gr Lehigh Brass solid

    and MAYBE some of Noel Carsons shorter ZA bullets, not sure yet...
    [​IMG]
     
  11. Chas1

    Chas1 Well-Known Member

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    Nice looking rig groper.
     
  12. kellyzier

    kellyzier Well-Known Member

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    Groper,,,
    NICE rifle.......It looks like a real shooter...whats it weigh??

    Also, do you have a real accurate hunting load? If so, whats your load info? It will be a great starting point for my 375

    thanks
    kelly
     
  13. groper

    groper Well-Known Member

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    Thanks for the compliments fellas,

    Truth be told I dont know what it weighs... didnt ask the smith and i havnt had it on scales yet, i will say that its not light. SS lilja Barrel tapers to 1.0 in at the muzzle over 34inches, so its quite heavy. The barnard P-chey action is a big heavy solid unit aswell. The bipod i havnt decided on either, the harris in the photo was just for the photo, it will be getting a much better unit when i decide on something, i HATE swivel stud mounted bipods....

    I have yet to shoot this beast, im still waiting on dies from CH4D. The smith put 3 rounds thru it using the 350SMK`s under 140gr AR2225 (retumbo) for a 1 hole group just to test everything was ok, thats it... So not alot i can tell you atm until my dies turn up and i can start doing some load development.

    initially i will work up some loads with the 350gr SMK, then ill move onto the 350gr predators as they are readily available here. In the mean time ill still be trying to get my hands on the GScustom and ZA bullets, but i anticipate a 6 month wait on these... ZA bullets are supposed to be ready for public sale in 2 weeks, but im not even sure if any of noels bullets will stabilize in a 1:10, im still waiting to hear back from him regarding some of the less "extreme" solids that may work.

    Ill order some rocky mountain bullets so long as i can find someone willing to send some to australia for me?
     
    Last edited: Jun 20, 2010
  14. the claw

    the claw Member

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    Very nice groper. Did Wilddog build that for you? I will build on a P Chey action as well.

    I would ultimately like something that is able to be carried around a bit, but I do have a couple of lighter rigs for the mountains over here...

    Really, the main thing for me at the moment would be securing a good supply of projectiles if I went with the 375. 338 is the easy option as I can get 300gr SMK's no problems and True Flite do barrels (34 inch 1 in 10 twist). It would also work out a bit lighter than a 375...