Long barrel question...

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by JARHEAD1371, Jan 10, 2009.

  1. JARHEAD1371

    JARHEAD1371 Well-Known Member

    Oct 9, 2008
    I am looking at building a long range deer rifle in 7WSM with a 28"-30" barrel. I was wondering if there is any type of calculations that I can use to estimate the bullet speed as compared to reloading data. A few years ago a buddy told me that every inch of barrel length over 24" adds about 50 fps. He was talking about the 7RUM pushing 140 gr bullet. I am wanting to compare the 168 gr and 180 gr VLD bullets for my setup. Any info is greatly appreciated.gun)
  2. KQguy

    KQguy Well-Known Member

    Dec 7, 2007
    I am having a 7mmWSM built right now,and my smith(Kevin Rayhill)told me a 26'' barrel is ideal,much longer than that,and it is a waste,he said you can actually start to lose performance if you go too long.I would contact him and talk to him about it,he probably knows as much about the 7mmWSM as anyone out there,he has built alot of them.Contact stockadegunstocks if you want to get a hold of him.

  3. geargrinder

    geargrinder Well-Known Member

    Nov 6, 2006
    I'm having my 7mmWSM made 28". If all else fails I can always push in my 7mmRUM reamer and still have enough barrel to get decent velocities.
  4. Rustystud

    Rustystud Well-Known Member

    Dec 25, 2007
    Most of the 1000 yard shooters shooting the 7mm or 300WSN that I know are shooting 30-32 inch barrels. Most of the hunting barrels I do are 26-28 inches.
    Last edited: Jan 11, 2009
  5. LouBoyd

    LouBoyd Well-Known Member

    Oct 15, 2007
    The computer program "Quickload" is excellent for predicting muzzle velocity vs barrel length for vaious loads. It's available in the US from NECO moly plating bullets,firelapping,ballistic software and chronographs. The velocity per inch of barrel lengh can vary a lot with such things as case capacity, powder, and bullet, and barrel characteristics. . Quickload takes those into acount. It provides many other parameters about time pressure and distance of a bullet in the bore. Unfortunatly it doesn't predict accuracy, since it does not predict the effects of bullet stability.