Page 1 of 2 12 LastLast
Results 1 to 10 of 13

Thread: .243 energy calculation

  1. #1

    .243 energy calculation

    A question for the more informed than I, please. I wish to calculate what my .243 CZ 550 is putting out as I have recently read an article by Bruce Potts of shooting times (2nd Jan2013 edition) which warns of the depleted speed and energy when barrels are shortened. My CZ has a barrel of 20.5 ins measured from the start of the chamber to the crown and an ASE Utra S5 muzzle mounted moderator. I have always been pleased with the results I get, which are almost always reasonably sized fallow bucks in the Essex area, and am not really considering changing rifles because of one article. However, a seed of doubt has been sown and as a result I have borrowed a chronograph from a pal to check out the speed and energy to reassure myself. Whilst it tells you how to operate the chrono it doesn't give the formula to calculate energy from muzzle speed. Any help and opinions would be appreciated.

    Regards,

    Gallmans

  2. #2

  3. #3
    Good link B500.

    Can also use -

    Mass ( in grains ) x Velocity Squared divided by 450240

    eg

    100 grain bullet at 3000fps would be 100x9,000,000/ 450240 = 1998.9 ft lbs
    Stalking, Courses, Gear - Moray Outfiiting Website here - Welcome
    BASC Approved Trainer & Assessor. Cairngorm National Park Authority Approved Supplier. Supported by Sauer Arms
    See you at the Stalking Fair, Scone & Moy 2017




  4. #4
    Many thanks. I have saved the link and the formula and will let you know how I get on.

    Regards,
    Gallmans

  5. #5
    in principle it is a best guess

    altitude, humidity and air temperature can impact muzzle velocity as significantly as barrel length and with a marginal bullet and barrel choice you could be very nervous by the time you do your calculations

    on the whole the deer don't know the difference and the FLO's don't carry Chronos for spot checks, and even if they did proving that the bullet you just fired is identical to the ones in the magazine for both MV and load would be a legal minefield!

    if you are concerned at all get a bigger rifle!

  6. #6
    Try one of these...no muzzle energy issues at all!

  7. #7
    Quote Originally Posted by Jager SA View Post
    Try one of these...no muzzle energy issues at all!
    Is that the new range of Lego?
    saw that in the Toys'R'Us brochure

  8. #8
    Quote Originally Posted by bewsher500 View Post
    Is that the new range of Lego? saw that in the Toys'R'Us brochure
    Meccano kit for Adults.

  9. #9
    Quote Originally Posted by Jager SA View Post
    Meccano kit for Adults.
    ah yes, I can see the plastic nuts and bolts

  10. #10
    Quote Originally Posted by gallmans View Post
    A question for the more informed than I, please. I wish to calculate what my .243 CZ 550 is putting out as I have recently read an article by Bruce Potts of shooting times (2nd Jan2013 edition) which warns of the depleted speed and energy when barrels are shortened. My CZ has a barrel of 20.5 ins measured from the start of the chamber to the crown and an ASE Utra S5 muzzle mounted moderator. I have always been pleased with the results I get, which are almost always reasonably sized fallow bucks in the Essex area, and am not really considering changing rifles because of one article. However, a seed of doubt has been sown and as a result I have borrowed a chronograph from a pal to check out the speed and energy to reassure myself. Whilst it tells you how to operate the chrono it doesn't give the formula to calculate energy from muzzle speed. Any help and opinions would be appreciated.

    Regards,

    Gallmans
    If you are achieving clean kills and chronographing shows that you are up to speed (MV & ME) you have nothing to worry about. If you are reloading you may benefit from using a slightly faster powder with the shorter barrel. e.g. my own Blaser r8 .243 struggles to reach the published MV data using H4831 but Vit N140 produces excellent MV & accuracy. atb Tim

Similar Threads

  1. Wish I had the Energy
    By Gazza in forum Deer Stalking General
    Replies: 1
    Last Post: 04-05-2013, 07:39
  2. Small bore, high energy
    By private fraser in forum Deer Stalking General
    Replies: 11
    Last Post: 17-08-2012, 12:30
  3. lead shot calculation - help pls.
    By sauer270 in forum Rifles & Calibres
    Replies: 0
    Last Post: 19-11-2011, 14:29
  4. Energy
    By PKL in forum Ammunition, Reloading & Ballistics
    Replies: 8
    Last Post: 11-11-2010, 23:48
  5. Dumping energy
    By caorach in forum Deer Stalking General
    Replies: 52
    Last Post: 04-03-2010, 13:44

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •