Cartridge design help please

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by cummin_un_glued, Nov 17, 2013.

  1. cummin_un_glued

    cummin_un_glued Well-Known Member

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    I want to build a rifle to drive the Matrix 165gr .277 bullets 3100-3200fps. I cant decide what brass to put behind this bullet to get the results I want. I am open to having a reamer made. I would like to use some combination of dies that are already out there like I do with my 7/300win using a redding s type bushing die. I would be open to having dies made or modified if I had to though.
     
  2. mitch260

    mitch260 Well-Known Member

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    Why not a 270 RUM. 338 rum brass and redding dies with a different neck bushing. I guess the down side might be barrel life. 270/375 ruger would be another good one, dies would be more of a problem though.
     

  3. HighCountryMulies

    HighCountryMulies Active Member

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    I have been wondering if Rich Sherman's new 6.5 ss case design could get close to those numbers in a short action... would be nice to have a true short action .270 round that could push the 165 close to 3200...
     
  4. cummin_un_glued

    cummin_un_glued Well-Known Member

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    I looked at the 338 rum case but I feel like it is a bit large. Now the ruger case I have been looking into more I keep trying to find the thread about necking it down to 7mm for the 7mmLRM but cant seem to find it now. Seems like it would likely do what I am wanting if I can neck it down easy enough.

    It will be built on either a weatherby vanguard/howa or a savage either will be long action.
     
  5. bigngreen

    bigngreen Well-Known Member

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    I think taking the 7 LRM and necking it down would put you easily into your performance window and it should be easy to make cases.
     
  6. mitch260

    mitch260 Well-Known Member

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    I thought that was the better choice too, but what about the reloading dies?
     
  7. Hired Gun

    Hired Gun Well-Known Member

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    A 270 Weatherby out to just get you there. A little longer barrel would ensure it.
     
  8. cummin_un_glued

    cummin_un_glued Well-Known Member

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    thought about the wby since I already have a 257 wby and love it. I want to keep the barrel to 26" including the break. also have thought about doing a 270 wby improved. move the shoulder forward a little bit, shorting the neck to say 7mm rem mag length should move the shoulder forward 050" it already has less body taper. could even blow the shoulder out to 40* and it would even have a 270 head stamp on the brass that way.

    thoughts?
     
  9. Hired Gun

    Hired Gun Well-Known Member

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    I'm not a huge fan of wildcats unless it's really going to make a difference. What you propose to the 270Wby should be enough to reach your goal. A longer barrel would be a lot easier. If I was going to wildcat it that much then I think I would go large. 270 STW, 270-300Wby, 270-300 Ultra, yada yada and next thing you know you're sporting a Chey Tac based 338. That's where this little game took us. Be on the lookout for the all new 338 CT Maxx.
     
  10. cummin_un_glued

    cummin_un_glued Well-Known Member

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    I already have a 30" barreled 300win based wildcat gun. I am wanting something easier to pack and it simply won't take that much case capacity to reach the speed I want. Also using the wby based wildcat would let me shoot factory ammunition........ if I wanted to pay for factory 270wby rounds....lol
     
  11. bigngreen

    bigngreen Well-Known Member

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    Hired Gun, have you built a 270 WBY that will make it into the 3100-3200 fps range with a 165 Matrix, I have wanted to build a 270 WBY but the guys I know who load them end up right at the same level I am with a 270 WSM so it's kind of redundant to own reamers for both.
    I can run the 270 WSM over 3100 fps with the 165's but it's pushing it with Retumbo and H1000, I suspect that R33 may let me run in the 3100 fps range but I'll have to wait till winter to put that barrel back on and test it.
     
  12. Hired Gun

    Hired Gun Well-Known Member

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    The only 270Wby I've built so far was a 24" factory 270Win barrel to start with. The guy was using 140 and 150's so I have no personal experience with the 165. Just looking at the conservative load tables and considering factory 270Wby ammo gets 150's out at 3245 I would think 165's in a 26" tube ought to hit 3100.

    The factory ammo has been detuned a bunch from where it was. I remember seeing the 270 hitting 3500 with 140 grain factory ammo. On a 257 Wby each inch is near 75 to 100 fps. If you are getting 3100 out of a WSM the Weatherby ought to smoke that by a fair amount.
     
  13. bigngreen

    bigngreen Well-Known Member

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    That seems about what I thought the 270 WBY should do but I have yet to find anyone who actually gets the numbers it seems like they should be able to, most guys are within 50fps of what I shoot my WSM's at though I run 26-27in barrels on them. The couple guys I have talked to running the 165 have been right at or slightly slower with the Weatherby but I don't know if that was where they ended up with accuracy OR that was where they topped out.
     
  14. cummin_un_glued

    cummin_un_glued Well-Known Member

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    I have not found any 270 wby data showing a 165 @ 3200 and I highly doubt that 1" of barrel is going to gain anywhere near 100fps with a 165gr bullet