B.c.

[Blammer]

Anybody know what the BC of the Lee 358-158-RF is?

it drops at 162gr for me.

Wanting to try to figure drop with it at 200 yds.

[Tom Myers]

Blammer,
Lee lists the Ballistic Coefficient for the 358-158-RF at 0.160
I am working at my computer today so I thought I would takea break and run my datbase info on this bullet through my new software that I am working on.

I do shoot this bullet in my Dan Wesson and it shoots pretty darn good.
This is what the Cast Bullet BC Calculator estimates the BC at.

http://www.tmtpages.com/LinkSkyImages/lee_358-158-rf/ClipBoard-4.gif

I use 12 grains of IMR4227 in the 357 mag case and it runs right at 1000fps and the ballistic path is very close to the calculation paths that the software calculates

http://www.tmtpages.com/LinkSkyImages/lee_358-158-rf/ClipBoard-2.gif

http://www.tmtpages.com/LinkSkyImages/lee_358-158-rf/ClipBoard-3.gif
Hope this helps,
Tom Myers
Precision Ballistics and Records (http://www.uslink.net/~tom1/)

[Blammer]

wow! that rocks!

My velocity I chorno is 1260 fps.

with the BC Point Blank shows 54 inches of drop at 200 yds.

Hmm, guess I'll need a rangefinder! and Turrets! thanks.

so when is your program gonna be available? :)

I love this boolit out of my 357 mag with 9 gr bluedot, that gets me the 1260 fps and it's accurate to boot at 25 yds! Really drops at 100yds, and I decided I'll probably go with my 180 gr at 1720 fps.. instead... :D

[Blammer]

got any BC info on that? 180gr FP? similar to the lee in nose profile just heavier...

[Tom Myers]

Blammer,
If the nose profile is very similar to the 150 grain bullet, you can estimate the BC by just increasing the BC in direct proportion to the increase in weight and then knock off about 7% to account for the increased drag caused by the extra length

Divide 150-gr. into 180-gr. to get 1.2
Next multiply the BC of 0.1794 times 1.2 to arrive at an increased BC of 0.2153
Now 0.07 times 0.2153 = 0.0151
Then 0.2153 - 0.151 = an estimated BC of 0.2002

Remember that is more than likely just a very rough estimation but it should put you in the ballpark.

You can refine the BC by comparing your sight come-ups from one range to another to your ballistics calculations and then adjust the BC that is entered until the predicted path matches the actual path. Then you can use that adjusted, tested BC to calculate accurate trajectory paths for different muzzle velocities.

The Program that I was using is to be the New Precision Ballistics and Records Version 3.1. In addition to being more user friendly, it will have some more features such as bullet and headstamp graphic options, head and tail wind trajectory adjustments and trajectory graphics. Right now the big hurdle is to make the Borland Database Engine that the software uses compatible with Windows Vista. When that problem is solved, it shouldn't be too much longer until the software is ready for distribution.

Tom Myers
Precision Ballistics and Records (http://www.uslink.net/~tom1/)

[Blammer]

thanks!