what velocity your getting ???

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by HunterGreen, Feb 17, 2014.

  1. HunterGreen

    HunterGreen Well-Known Member

    Messages:
    251
    Joined:
    Jan 14, 2014
    Does anyone honesty have and chronograph a 7mm mag in a 30" barrel ???

    Is so what speeds are you getting ??
     
  2. Max Heat

    Max Heat Well-Known Member

    Messages:
    385
    Joined:
    Feb 26, 2012
    What bullet weight are you talking about?

    I only have #s for a 26" barrel though.
     

  3. HunterGreen

    HunterGreen Well-Known Member

    Messages:
    251
    Joined:
    Jan 14, 2014
    140 ballistic tip
    162 amax
    168 bvld
    180 bvld
     
  4. J E Custom

    J E Custom Well-Known Member

    Messages:
    7,312
    Joined:
    Jul 29, 2004
    I used to shoot a 7 mag in competition that had a 29.4" barrel. I used 168gr SMKs and loaded 66.5
    grains of H 4831 for 3200 ft/sec. I bumped it a little and got 3254 but in hot weather it would blow the primers (To Hot) so I would be VERY careful when you get in this neighborhood.

    Also I used DWM cases because regular brass would not hold up for 2 or more shots.

    I do not recommend using loads this hot and would suggest that you start low and work up until you see pressure signs and back off 1 grain. Velocity will be different in different barrels so you will just have to live with what you get.

    If you are not sure about the chroney results, do a bullet drop test from 100 to 600 yards and this will verify velocity.

    J E CUSTOM
     
  5. HunterGreen

    HunterGreen Well-Known Member

    Messages:
    251
    Joined:
    Jan 14, 2014
    Wow thats smokin,

    I have 1 month to make up my mind on barrel taper and contour.

    It will @30 , I measured the stock barrel on Remy and its 1.230 at breach. Would like to have that for 7-8 inches than taper to .900
     
  6. AZShooter

    AZShooter Well-Known Member

    Messages:
    2,075
    Joined:
    Dec 12, 2005
    I had one. Got up to 3085 fps with 180 Berger VLD and RL-25 with bullet firmly into rifling. Accuracy was best at 3055 fps

    Later the 1 in 7 twist 3 groove caused the VLDs to diverge from POI and much to my dismay at round count 236 while shooting at a coues wt!!! ( Lesson learned about too much twist with a 3 groove)I had to borrow another rifle to finish off the wounded animal. You can imagine how happy I was at that moment. Good old Murphy's law.....

    Switched to target VLDs which lasted another 75 rounds then THEY became damaged. Moly coated them and within 50 rounds THEY were damaged too! Finally moved to moly coated 150 E-tips, 140 and 160 accubonds and used them for a while till I got bored with the ho hum wind drift numbers and rebored/rerifled it to a 338 RCM. It was retired with 875 rounds through it and it still shot very accurately.

    moly coated 140 accubonds were very accurate velocity 3422 using RL-17
    moly coated 150 E-tips also accurate velocity 3350 using RL-17
    Also tried some moly coated 160 accubonds velocity 3320 using RL-25

    Ross
     
  7. HunterGreen

    HunterGreen Well-Known Member

    Messages:
    251
    Joined:
    Jan 14, 2014
    Interesting lessons,

    I will stick with 1-9 twist
     
  8. J E Custom

    J E Custom Well-Known Member

    Messages:
    7,312
    Joined:
    Jul 29, 2004
    A 1 in 9 is my preference also.
    My target rifle was a 1 in 9 1/4" and shot 1/2 moa @ 1000 yards with me at the helm (The rifle would shoot better than I could prone with no rest/Bags.

    It is now doing duty as a 7mmSTW (We re chambered it to clean up the throat) and it still shoots very well with 3000 + rounds down the tube.

    J E CUSTOM