375 Cheytac Questions

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by danpd13, Aug 29, 2009.

  1. danpd13

    danpd13 Member

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    Hi There,

    Have been a member on this forum for a while now, but never posted. there is a wealth of great stuff on here and i find myself spending hours reading it.

    I am based in the UK and i would really like to build a 375 Cheytac. In an ideal world i would just go with a Lawton 8000L plus barrel and muzzle brake, Manners T4A stock, and away i go. But i can't find anyone who imports Lawton stuff in the UK. all my other rigs have been built on Stiller actions, either Tacs or Predators.

    I know Lawton seem to be the people with the most experience in this caliber, other than Kirby's 375 AM, or the 375 Snipe-Tac, but i need to build this rifle with components which i can get readily here in the UK, so i was thinking of going with a single shot Predator XL or TAC 338, and then adding a barrel, possibly Walther, but am open to suggestions.

    The part where i am stumped is the correct barrel twist rate, and whether or not i should be concerned about the bore diameter of non Lawton barrels, i know they produce slightly over size bores to accomodate high BC solid bullets.

    I will most likely be using 350gn SMKs and GS Custom SP bullets. shooing to sub 2000yds, (which is about half the length of england!!)

    Any help, info, or advice would be most welcome,

    Regards

    Paddy
     
  2. Down Under Hunter

    Down Under Hunter Well-Known Member

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    Paddy,

    Welcome to the board !

    When you find the answer to the question about twist rate.. Let me know too.

    This is the grey area with this calibre. So many views on what to go with , hey ?

    I love the idea of the calibre as well for the performance but I am confused too. I would want to shoot both solids and lead core bullets on game at range. It think Lawtons LR bore will shoot both and I think its 1.11.5 ? COuld be wrong.

    Dont mean to sound stupid, but cant you import an action yourself ? We can on Aus .

    DUH
     

  3. danpd13

    danpd13 Member

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    Hey DUH,


    I was thinking of the 1-11.5 twist, but then i read a whole load of different articles with different twist rates.... and got all confused!!! i thnk i will be happy just shooting the currently available bullets now, and if something incredible happens in the future then i will re-barrell.

    re importing an action, i am not a firearms dealer so it makes it difficult, plus there is a $400 fee for an export license, and as i am not a distributor/dealer i won't get favourable pricing.... once you add import duties etc, it makes it rather an expensive proposition, so it would be better to find someone who already has the necessary paperwork/contacts in place.

    regards

    Paddy
     
  4. Joel Russo

    Joel Russo Official LRH Sponsor

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    You cannot build a .408 based wildcat on either of those actions! They are designed for the .338 Lapua case.
     
  5. danpd13

    danpd13 Member

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    Hi Joel,

    I was only going by what my friend who is the SPF agent over here was told when he spoke to Curtis at Stillers. I guess he must have meant the Python action then?.He just told me that from time to time they do a run of big actions which can handle CheyTac based stuff, and if i want one i should say ASAP, as they just happen to be doing one right now.

    do you think i would be wrong to use a Stiller action for this project?
     
  6. 358sta

    358sta Well-Known Member

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    Sounds like you were told about Stillers new TAC 408, Cheytac sized case action with pinned .300 recoil lug going for $950, but you weren't given or remembered the name. If you can't get the Lawton, I'd recommend going with Stiller's TAC 408.
     
  7. Joel Russo

    Joel Russo Official LRH Sponsor

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    Correct. However I strongly disagree on building on the Lawton over the Stiller.
    The quality of the Stiller far exceeds that of the Lawton.

    I have a few on the Lawton, and building one on the new Stiller TAC 408 now.
     
  8. danpd13

    danpd13 Member

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    Thanks for that tip Joel, it makes life a lot easier for me!!

    what barrel would you reccomend? or would you still go Lawton? I would prefer to have the barrel Pre-chambered to save on reamer costs over here. do you think the 1-11.5 twist is a good choice?
     
  9. Joel Russo

    Joel Russo Official LRH Sponsor

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    Personally I would not build on a Lawton barrel either. Been there, done that, learned my lesson the expensive way.
    Hard to beat Krieger, Benchmark, and the others that are doing well on the bench rest side of the house. I know Benchmark will make you a .375 barrel. The 11.5 tw will work with the bullets you spoke about in your earlier post.
     
  10. whin4

    whin4 Active Member

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    Check out the Barnard actions, www.barnard.co.nz, They make an action for the 408 case and exporting out of New Zealand is no problem.
     
  11. LR3

    LR3 Well-Known Member

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    Paddy, here's some discussion by the experts from previous posts. I have both a 10 twist 375 and 12 twist 375 and both are very accurate. One is a Krieger barrel and the other a McGowan:


    Re: 375 Snipe Tac...Barrel and Bullet tests
    I just came back from testing the new style 350gn SMK.

    Seated .015 off the lands.
    Retumbo powder
    Fed 215M

    140grns ave fps 3149 ES 8

    142grns ave fps 3211 ES 9

    I fired the 140grn loads at my 700 yard plate, 8.75moa added...all three shots landed on steel, spread was about 4" The cases extracted easy, no marks on case head at all.

    The 142grn load was .5 moa less, all shots landed on steel as well. The cases extracted easy, just a bit of shiney mark on case head. Temp was in the low 80's I used .770 for the BC in Exbal, came out perfect. This is one big Thumper!


    700 yard steel target

    Cowboy-Dave
    [​IMG] 08-16-2008, 02:46 PM
    Fiftydriver [​IMG]
    SPONSOR
    Join Date: Jun 2004
    Location: Fort Shaw, Montana
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    Re: 375 Snipe Tac...Barrel and Bullet tests
    Dave,

    Sounds like your new 375 is working well for you.

    Why did you move the shoulder forward compared to your 338 Sniper Tac?

    Your loads look right where they should be comparing them to the tests I have run on my 375. I am getting 3250 with 143 gr of Retumbo and 3300 fps with 146 gr.

    Like you are seeing, they are very friendly in warmer temps compared to the 338 siblings. Just wish there were more bullets available but the 350 gr is good enough to get the rifles shooting well.

    I am not a fan of the solids, certainly they are ballistically impressive but to bore sensitive and not usible for big game hunting. Not even legal to use here in Montana on big game and I beleive there are other western states that require an expanding bullet for big game. With enough interest maybe we will get some more bullet options with a lead core bullet design.

    Ya need to double your range and see how your lightweight rig runs for you.

    That is a unique gong design. Good use of scrap metal however!!! May be trickier to hit at longer ranges though.

    Anyway, good looking rifle.

    Just curious, why do you not make your own muzzle brake? If you want something that will really tame down your rifle, let me know and the PK brake will make a believer out of you!!! LOL

    Take care,
    __________________
    Kirby Allen(50)

    [​IMG] 08-16-2008, 05:26 PM
    Black Diamond 408 [​IMG]
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    Re: 375 Snipe Tac...Barrel and Bullet tests
    Kirby,
    I normally make my own brakes, but like you know...when your busy its hard to work on your own guns. Yes your PK brake works real well, i did one similar on a 408 several years ago. When i get my CNC Mill up and running i can do more of that type of machining. The Lawton brake will be installed later on a customers rifle, and ill put one of mine on this boomer.

    My original 338 snipe tac has the same case profile, when i put some of the taper back into the case i shortened it just a bit, all during the R&D phase, It worked well so i just stayed with it. Either one has plenty of case capacity and if i use the cheytac magazines they will still feed from them, any longer and they wont fit at the shoulder retaining area.

    I am surprised the solids shot so good in a 12 twist, they are mostly for shooting vermin or steel at long distances.

    I was out looking at my range today, max distance is 700yds, there is a county road right behind my shooting table, if i go across the road i have another 800yds or more, but i have to do some figureing, there is a set of electric lines that crosses my line of sight. Im sure at 1500yds i would be way over them but need to make sure first.

    I have lots of 1/2" steel plate, 3'x4' square, but the darn bullets dont want to stop when they hit it. yea i wish the AR400 drops i have were bigger, lots of small pieces.

    I think i will stay with the 142grn load, it seems to work good and no real pressure signs.

    Have you experimented with different twists?

    Dave
    Black Diamond 408View Public ProfileSend a private message to Black Diamond 408Send email to Black Diamond 408Visit Black Diamond 408's homepage!Find all posts by Black Diamond 408

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    Re: 375 Snipe Tac...Barrel and Bullet tests
    I have tested the 1-10 and 1-12 from Lilja and Krieger. With the 350 gr SMK I have never really seen any NEED for the 1-10 but use it more then anything simply for the reason I am hoping soon we will have some very long 370-380 gr aluminum tipped lead core bullets to play with!!!

    At the velocities we are using the newly designed 350 gr SMK has no issued in either twist from what I can see so far as far as overspinning them.

    I did take some of my last TTI cases and form them up. As you know they will take alot more pressure then the Jamison hulls. Got the 350 gr SMK up to 3445 fps with very practical base life, 5 firings per case is where I stopped testing.

    I had several of the early SMK design come apart at these speeds in the 1-10. I have also had a couple instances where the new design has mysterious failure to impact issues at 1500 yards. I can only come to the conclusion that this was due to a weakening bond between the core and jacket. There was no visable blue-grey puff by my spotters and bystandards but they did not make it to the target or land close enough to make it obvious where they hit??????

    At 3300-3350 fps I have never had any problems at all in the 1-10. Like you, I keep things in this level to keep pressures lower, still plenty of punch!!!

    I had a couple custom contoured barrels made for me by Dan Lilja, They are actually lighter then a #8 contour barrel with a 1.250" shank diameter. They will finish up at 32" in 338 and 30" in 375. I suspect they will get me down to under 16 lbs with a conventional A-5 stock and BAT Model M receiver. Have to just find time to get away from customers projects and spend some time on a couple of my personal ones.

    That will likely not happen until well after big game season!!!

    Take care, keep us posted. For extreme range steel slappin, those solids sure look like the trick!!!!
    __________________
    Kirby Allen(50)

    Allen Precision Shooting
    Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

    Farther, Faster and Flatter then ever before.

    kballen@3rivers.net
     
  12. danpd13

    danpd13 Member

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    Wow, thanks for that LR3, i had seen most of these posts, but its great to have them altogether in one place.
     
  13. Black Diamond 408

    Black Diamond 408 Well-Known Member

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    Dan,

    If you want to PM me i can possibly put you in contact with a customer of mine in the UK that is importing a rifle from me. He will have all the information you need.

    Barrels,
    The Benchmark 11.5" button barrel is very good for all bullet types jacketed or solids. He also can do the cut barrels for a special twist rate. 12" works good for the 350smk, but a faster twist is better. Lilja now offers a 10" twist for the large and long barrels. I have a new Bartlein Gain twist barrel i am installing on my personal rifle, it has a starting twist of 16", then it tapers to 7.85" at the muzzle. This was ordered for the longer high BC bullets that are becoming more available. It too should shoot the 350smk well. I have several 10.5" twist barrels in the build stages as well. So in short you will be fine with any barrel from 10" up to 12" twist rates. These big bore rifles are pretty forgiving.

    Dave
     
  14. 436

    436 Well-Known Member

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    While in Arco Id, when Warren Jenson was at Lost River Ballistic'..., I was doing ballistic research for another company; on another caliber, bullet and cartridge project; I watched the 408 Chey Tac growing up... At the time I was thinking; how nice a slightly shorten version of the cartridge; or the 408 case itself might be in a 375 cal. I was thinking very hard on Pac Nor product and having them make me up a 1-10 Polygonal barrel'..., back in those days... Perhaps some one of you may have already tried the Pac Nor barrel I'm speaking of... In the end, like most projects another one got in the way and I never went back to it. I probable should have with their bullet manufacturing machine they had at the time, all that was needed was too tell the machine what design(s) you wanted and bingo'..., you had it in hand step into the back room loaded it; move to the next room and fired it..... At that time I was thinking of a .375 cal in something close to a .375gr. Lost River {sold} bullet. Would it have worked? Who knows?:rolleyes:
    436