270/7mm Rem Mag Build

Discussion in 'General Discussion' started by cummin_un_glued, Jul 15, 2014.

  1. cummin_un_glued

    cummin_un_glued Well-Known Member

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    I built a 7x300 last year and its an amazing rifle but its a little too much to pack up in the mountains being that its 51" long and weighs close to 17 lbs.

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    I wanted to use the black/grey/white McMillian stock from the 7x300 and replace it with a tan/grey/black McMillian, which means I have to use another weatherby vanguard rifle to start with. So I ordered another one to those which I got today. I already have one in .257 weatherby and am very happy with it.

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    I like the wind bucking capability of the .674bc 180gr bergers that I been shooting and I wanted something in the 160ish grain class of bullets in order to be able to take elk at 800y if needed. In order to get the energy I want I need a muzzle velocity of around 3100fps. A 7mm 168gr berger hunting hybrid has a .604bc which is good but realistically getting that bullet up to the 3200 range it would take i'd be back to my 7x300. So then I looked at the 165gr .277 Matrix bullet. It has a .650bc. Now a standard 270 Win is only going to push that bullet around 2900fps. This makes a 270 Weatherby mag come to mind but the factory accumark twist rate is only 1-10 which isn't enough.

    Dan Lilja builds .277 barrels in 1-8 twist so I contacted him and ordered up one of his #5 fluted match grade barrels. It will be here in 10-12 weeks. Being that i'm not going with the factory accumark means that I don have to use the weatherby brass. I will be using 7mm rem mag brass and simply necking it down using redding S type bushing dies just like I do for my 7x300

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    I already spoke with the gun smith that built my 7x300 and he just happens to already have this reamer and a .277 throating reamer so that he can throat it long enough for me to seat the rounds at 3.500" mag length of the vanguard internal box. All I have to do is make up a dummy round and send with the barrel and barreled action and he will ream it to match. I ordered 400 of the matrix bullets but they have not arrived yet so just for fun I necked down a piece of once fired brass and seated a 150gr NBT .277 bullet into it at the 3.530" length just for a visual reference.

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    Yall know how long a custom build takes so progress will be slow. How ever I do plan to hunt with the 7mm rem mag that I just ordered this fall in WY since this rifle wont be done yet. I will update this thread as parts arrive and progress is made.

    Let me know what yall think.

    Dustin
     
  2. Dick Tinsley

    Dick Tinsley Well-Known Member

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    I like it!!! Got me to thinking now!!:):D
     

  3. bigngreen

    bigngreen Well-Known Member

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    I'm kinda stoked to see how it performs, I've built a number of 270 WSM's but I've always wanted to see the 165's from a belted mag case since those are just plug an play when it comes to feeding from the mag. The 165 Matrix is probably one of my favorite bullets to put on elk, really looking forward to seeing how this build performs for ya!!!
     
  4. cummin_un_glued

    cummin_un_glued Well-Known Member

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    Thank you sir, i'm looking forward to it as well just wish it didn't take 6 months to get one built lol
     
  5. elkaholic

    elkaholic Well-Known Member

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    Great job Dustin! That should be a really good performer. I have an 8 twist Lilja on my 6.5 Sherman and it has been a good shooter. Be sure to keep us posted when you get it up and shooting........Rich
     
  6. calhunter805

    calhunter805 Well-Known Member

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    Tag in I'm really interested in this build.
     
  7. Dick Tinsley

    Dick Tinsley Well-Known Member

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    Now I'm really thinking about this build. Wonder how fast it would push a 140-150grn? I'm really thinking about this now!! It's all your fault Dustin!! Lol
     
  8. cummin_un_glued

    cummin_un_glued Well-Known Member

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    Well guys we all know how long these builds take but I thought I would keep everyone up to date as to where I am at to this point.

    I have the vanguard rifle in hand now and tonight I put a 20 moa base on it and tomorrow i'm going to swap the vortex 6-24 HS off of my 257 onto it along with the stock off of it so that I can start working up a load for it as it is now.

    I have been emailing Lilja about the barrel and it looks like i'll be having him make me one with a custom contour to try to get the weight where I want it. As soon as I make my mind up that will get ordered.

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  9. calhunter805

    calhunter805 Well-Known Member

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    If you don't mind me asking what smith are you using?
     
  10. cummin_un_glued

    cummin_un_glued Well-Known Member

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    No problem at all, I am using Kevin Weaver of Weaver Rifles in CO
     
  11. cummin_un_glued

    cummin_un_glued Well-Known Member

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    Just another update while i'm waiting on the barrel to arrive. Thinking about selling my 257 weatherby so I stole the stock off of it and I got my 20 moa rail in.

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  12. fmajor

    fmajor Well-Known Member

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    Their shop is about 30mins from my house!

    Does he have the reamer that was used in your 7mm/300Win build?
     
  13. cummin_un_glued

    cummin_un_glued Well-Known Member

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    Yes sir he does and he also has throat only reamers so he can dial the chamber to the bullets your shooting
     
  14. fmajor

    fmajor Well-Known Member

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    That's great news!

    I'm a ways out from starting my build, but it's good to know the sources so I can plan accordingly.

    I hope your new build does what you're looking for it to do!