bullet weight ballistics calc.

ripper007 · Member Joined: Mar 05, 2006 Posts: 199 Location: Colorado

in the point blank program. on the ballistics calculator,

I changed the bullet weight from 150 to 1. the distance for range and elevation did not change ??
and the velocity stayed the same.
I did notice that the energy change in the program.

I am still learning how to get around in this program.
remember, I just started reloading my own bullets about a month now.
and yes, I have been doing alot of reading. I bought the 2 volume set of Hornady books. and have about 3 other books on reloading. I am learning slowly, but safely.

the info I had put in the program was for a 30-30
hornady 150 grain bullet.
IMR 3031 powder.
cci 200 lr primer.
not real sure about powder grain. think it was 35.5 ??

popgun

Hey and welcome to HuntingNut. I can not answer your question because of a lack of information. For the graph to work correctly this information must be entered. Bullet weight, BC, and muzzle velocity, temperature, scope height and target distance.

If you are looking for the BC of a factory round there is a feature in Misc. Functions where you enter bullet weight and muzzle velocity and 100 yard velocity. That information will usually be found on the ballistics page of the particular factorys website.

Point Blank can not give you the velocity figures in any gun from any particular powder/charge combination. That information is gained from firing over a cronograph.

The great thing about collecting your own information is that you cover all the variables and enter them into Point Blank and then can play with variables to see what happens to the bullet path. For example you enter the ballistics information from your day at the range for a particular load, say your 35.5 grains of 3031. You enter the average velocity, the bullet BC, temperature and the range elevation that you were shooting at. Once you have that info added you can see the difference in flight caused by temperature , velocity, and elevation changes by playing with the numbers and clicking the Re-compute button on the Ballistics Calculator page of Point Blank.

When entering factory information you are entering their velocity fired at their standard elivation & temperature. That 'standard' information probably varies between manufacturers because there is no industry standard for advertised velocity. They usually (not always) have a note somewhere on their site telling you what their standard is.

Stick with it because all of this flood of information you are reading about in the reloading manuals will click and come together.

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

Weight per say, as entered in PointBlank (or theoretically any other ballistics program) should only affect the energy calculations.

See "weight" or "mass"... is already figured in when the Ballistic Co-efficent is created. The value which quantifys how much the bullet slows down as it travels through air. Bullet Shape and mass dictate how high or low this value is. Once BC is known, entering in the projectiles mass is only used to calculate the energy at range.

It might seem strange at first but its working as intended Smile

-DallanC

ripper007 · Member Joined: Mar 05, 2006 Posts: 199 Location: Colorado

Thanks,

understood now.

by the way, great program.