BC and also Trajectory "Advanced"

Vince

Gidday Dallan, I would like to put my cast 30.30 loads into PB but cannot because it requires a BC for the bullet. From your vast experience and knowledge (grovel grovel) is there a method of determining a BC for a cast bullet or is there a way or circumventing (thats my big word for the week) PB requiring a BC?

Trajectory: I have no problems bringing up a trajectory for a load. Now, I assume that the Advanced window is to put other trajectories on the grid for comparison? How do I go about using this feature? I have tried everything I can think of to no avail. The Help file doesn't give me enough info to work it out.

Cheers, Vince

1895ss

Vince, you need the bullet weight, muzzle velocity and the velocity at 100 yrds and Point Blank can calculate it for you. You'll find it in the miscellaneous functions. Hope it helps.

Vince

Thanks for that mate. Now I wonder if my mate will let me put his chrono out at 100m for me to shoot over with my Model 94? Hm, could be a problem here.

Cheers, Vince

1895ss

Better to use his then your own......... Very Happy

Jack · Member Joined: Oct 19, 2005 Posts: 98

I think there was a chart in the back of one of the issues of 'Lyman's Cast Bullet Handbook' that listed the BC of the bullets from their molds.
Listed them by mold number, IIRC.

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

Opps. Sorry I missed this until now...

Vince wrote:

Gidday Dallan, I would like to put my cast 30.30 loads into PB but cannot because it requires a BC for the bullet. From your vast experience and knowledge (grovel grovel) is there a method of determining a BC for a cast bullet or is there a way or circumventing (thats my big word for the week) PB requiring a BC?

1895ss is right, you need muzzle and 100 yard velocities and and PointBlank can compute the true BC. Most MFG values are off a bit from real world values so its useful to test factory BCs sometimes.

Quote::

Trajectory: I have no problems bringing up a trajectory for a load. Now, I assume that the Advanced window is to put other trajectories on the grid for comparison? How do I go about using this feature? I have tried everything I can think of to no avail. The Help file doesn't give me enough info to work it out.

Cheers, Vince

Advanced Trajectory is for comparing different trajectories... I personally HATE how it works and I am taking that into account with the next version.

The way it works is you compute a normal trajectory then you entered the Advanced Menu. The last load you computed is now in the #1 slot. You need to "copy" it into other slots, then go back, compute something else, enter advanced and copy that over... repeat until you get all the loads you want in there and you can compare.

It sucks... sorry, I dont know what I was thinking at the time (well I do... it was because of how I stored the data that made it a pain to access).

V2.0 will store loads independantly and in the comparison view (note the name change) you can access "pull down" boxes to select and compare any load with any other load without even touching the ballistics menu.

-DallanC

Vince

Gidday Dallan,
Thanks for the guidance mate. Don't loose any sleep over taking a little time to answer.....I know you are a busy man and do this out of the goodness of your heart.......I am assuming you don't get any recompense from the work you do.

Going to try and get a 100yd velocity, if not then the performance on the target will tell the story.

Cheers, Vince