7Rm vs. 7stw

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by linksmechanic, Jan 25, 2009.

  1. linksmechanic

    linksmechanic Well-Known Member

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    I was just looking at the hodgdon reloading site and was entering info for the stw to see if it would be worth reaming my rm to stw. They list a 175 grain bullet with retumbo at a maximum velocity of 2967. I'm currently shooting a max load in my 7rm with 68 grains of retumbo and shooting 180 bergers an am getting 2950 fps. What gives? It seems by there data you gain nothing. Am I missing something here. My load is a little hot but there is no pressure signs and is listed as max on there site.
     
  2. Derek M.

    Derek M. Well-Known Member

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    The probability of having to download the hotter 7s, (STW, RUM, etc.) for better accuracy is greater than 50%. The 7 Rem Mag is, IMO, the ideal case size and shape for 7mm, with the WSM coming in a very close 2nd. I like the Dakota as well.
     

  3. J E Custom

    J E Custom Well-Known Member

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    All of the reloading manuals are conservative. So you have to work up to the potential
    of each cartrige.

    With the same barrel length and max load for each round here is the difference.

    The 7mm RUM produces 24 percent more energy than the 7 Rem Mag and 12 percent
    more than the 7 STW.

    And because of case capacity the bigger 7mm RUM will propel a heaver bullet as fast as
    the lighter bullets in the 7 REM.

    Don't get me wrong I shot a 7 REM MAG for 1000 matches and it was very good ( I used a
    168gr SMK @ 3254 ft/sec ) but it was very hot and with the 7 mm RUM this would be a
    mild load in the same length barrel.

    The reloading manuals are just a starting point.

    J E CUSTOM
     
  4. Long Time Long Ranger

    Long Time Long Ranger Well-Known Member

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    The STW will shoot quite a bit faster than the rem mag. I have done quite a bit of work with the STW and the 7mm-300 wby and they are well beyond the reach of a 7mm rem mag. It depends on your barrel length. I wouldn't rechamber if your barrel is 24". I just never saw a purpose for the 7mm rem mag. You can virtually match it with a blown out 280 case, less powder, noise and recoil. If you want to improve on the blown out 280 then you have to go up to the STW or 7mm-300 wby. Now with the 7 WSM performing right in there with the 7mm rem mag I think it is a dying cartridge.
     
  5. baldhunter

    baldhunter Well-Known Member

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    I have both the 7mag and the 7mmSTW.The 7mmSTW will out shoot the 7mag,and should,but you have to use the right powder for it to really get it to jump way ahead of the 7mag.I get 3200fps with a 150gr. bullet using IMR-4350 in my 7mag.I get 3450fps with a 150gr. bullet using Winchester WXR powder with the 7mmSTW.The WXR is a double based powder much like Reloader-22.I could only get a velocity avantage of 75-100fps over the 7mag with the single based powders,H-1000 and IMR-7828.I never used the double based powders in the 7mag to see what it does with it.I like them both,but I think the 7mag case is more efficient.
     
    Last edited: Jan 25, 2009
  6. linksmechanic

    linksmechanic Well-Known Member

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    Thanks for all the info. I have a wsm and I get more velocity with the rm. I started getting pressure at about 2835 with the wsm and the rm I didn't get pressure till about 3000 which seems excessively high to me but what the hell. I like the wsm case but don't see to much of an advantage. There's a little less strectch but wih the norma brass I've got 15 firings before I had to tell my self to throw them away. As far as the Rm becoming a dying cartridge I would say not in my lifetime.
     
  7. trueblue

    trueblue Well-Known Member

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    I shoot a 7 STW and like it over a 7RM. It gives me as good if not better velocity than a 7RM without having to push it to hard.


    DerekM,
    Isn't the ballistics of the 7 Dakota and 7 STW about identical ? How can you like one and not the other ?
     
  8. Derek M.

    Derek M. Well-Known Member

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    Where did you read that I do not like the STW?

    I like the shorter powder column the Dakota offers. I like the STW just fine, just not as much.
     
  9. 3006savage

    3006savage Well-Known Member

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    The STW will not have much separation in a 24 inch barrel. That is what many of the reloading manuals are based on. The STW will really pull away with a 26" and especially a 28" tube because its larger case will maintain the pressure curve longer than the RM can. Also the manuals in general offer a greater variety of loads for the more popular cartridges and will tend to have a better shot at that optimum combination which maxes out the cases potential.
     
  10. trueblue

    trueblue Well-Known Member

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    DerekM,
    My apologies. I misinterperated your post.
    JIM