B.C. Correct answer ?

4570Ranger · Member Joined: Dec 17, 2005 Posts: 26

Have a question:
In the B.C. calculation,0.700 is very high.
But, is this correct ?
Here it is:
For a 265gr,45 Colt,I used 1023 FPS at the muzzle.994 FPS for 100 yards.
The answer is 0.700.
I feel, this should be lower.
This is more for real world shooting.
Thanks.

Pumpkinslinger · Posted: Tue Sep 25, 2007 12:32 am Post subject: Re: B.C. Correct answer ?

When I played with the the PointBlank software I got the same results but my question is where did you get the velocity values? Are they actual measured values or theoretical? When I plug in the muzzle velocity of 1023 fps and use a Speer 260 grain JHP from the bullet data base I get a 100 yard velocity of 926 fps.

SwampFox · Posted: Tue Sep 25, 2007 8:15 am Post subject: Re: B.C. Correct answer ?

Guys,
The BC for the Hornady 250 gr .452 bullet is .146 The BC for the Sierra 240 gr .452 bullet is .15 The BC for the Speer 260 JHP is shown by Speer at .183 I think the .183 number is a bit high but you can use that number if you wish. Were I wanting to do an actual calculation I would use a .16 number.

The problem you have is you used an over optimistic velocity at 100 yards with 994 fps.
Ed

DallanC · Site Admin Joined: Jan 18, 2005 Posts: 3572 Location: Utah

Yup, the above responses are correct. .700 is incredibly high for a bullet of any form, expecially a pistol bullet. I'd suspect the 100 yard velocity value.

One should note, that out to 100 yards velocity values are critically important that they be accurate. The farther out the velocity is measured the more accurate the BC calculation will be.

-DallanC