# Thread: calulating energy ft/lbs ?????

1. ## calulating energy ft/lbs ?????

Hi

can anybody tell me or calculate for me the ft/lbs energy that the 2 loads below will produce ??????

load 1= 243(federal brass), 31 grains of n150, OAL 2.670 , sierra 100 spitzer bt(1560) , mean speed 2534 fps

load 2= 308(sako brass), 42 grains of n150, OAL 2.756, sierra 150 grain spitzer bt (2125) , mean speed 2405 fps

Many thanks

ATB
Dave

2. [QUOTE=223;371487]Hi

can anybody tell me or calculate for me the ft/lbs energy that the 2 loads below will produce ??????

load 1= 243(federal brass), 31 grains of n150, OAL 2.670 , sierra 100 spitzer bt(1560) , mean speed 2534 fps

load 2= 308(sako brass), 42 grains of n150, OAL 2.756, sierra 150 grain spitzer bt (2125) , mean speed 2405 fps

Many thanks

ATB
Dave[

http://www.beartoothbullets.com/resc...php/energy.htm

Mike

3. bloody hell that was quick ,thankyou

ATB

Dave

4. The way I always use...

Velocity x velocity x bullet weight divided by the magic number 450240 gives muzzle energy in ft/lbs

Not quite sure where the magic number comes from but I know part of it is that there are 7000 grains in a pound

5. The figure I use is: Divide by 450400 from my Lyman Manual. So, as given in a previous post, Bullet weight x Velocity x velocity, divide by 450400 = ft/lbs energy. Obviously downrange vel. & energy are important too.
 Your .243 = 1425.65 ft/lbs & .308 = 1926.29 ft/lbs

6. Don't mean to hijack the thread but I'm curious about how to get the recoil energy?.

7. Originally Posted by private fraser
Don't mean to hijack the thread but I'm curious about how to get the recoil energy?.
Not so quick this time, but:

Rough data:

http://www.chuckhawks.com/recoil_table.htm

ATB

Mike

8. Thanks Mike, well done.

From the second link it looks like the .600 nitro express is a real Desperate Dan gun

fraser

9. I think recoil is quite a subjective thing and also dependsa lot on stock design. I have not fired a .600 nitro, but have shot .577 nitroand .50 BMG neither of which were particularly unpleasant to fire. Conversely, ashooting companion had a .300 WM which was very anti social until he changedthe stock from wood to synthetic. A chap I know also had a deer legal .44 whichwas no fun to zero. Both of these calibres produce a fraction of the recoil ofthe big bores, but for some reason I didn’t get on with them.
Mike

10. One of the reasons I was asking is that when I took the dsc1 I used the basc rifle, a 6.5 x 55 Tikka T3. This was nice to shoot and easy to keep the sight picture when taking the shot.

For many reasons I later got a .308 which I really like but the recoil is such that I can't keep the sight picture. Long story long..I'm thinking of getting a .308 load which equates to a 6.5 in recoil.

Sorry .223, I'm hijacking the thread a bit but hopefully it's of interest.

fraser

#### Posting Permissions

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