Bullet design?

[shooter93]

I was wondering what program 45 2.1 uses for designing the bullets I see here. Thanks.

[Buckshot]

..............You could send him a PM. I sure don'tknow.

................Buckshot

[45 2.1]

I don't use a program. I do draw the boolits useing AutoCad, but all it does is draw the boolit, if you know how. What I do involves useing what i've learned from the school of hard knocks and endless experimentation. No program out there will think for you. If you do find a program that does more than draw what you tell it to, tell everybody about it. Tom Meyers is tweeking a boolit design program of his own. Maybe he could tell everyone some of the parameters he uses on this.

[Tom Myers]

I do admire 45-2.1 for his ability to render quality bullet drawings from Auto Cad. When I first started to evaluate bullet designs, I tried to use a basic version of an Auto Cad software and became so frustrated that I wrote software that would both draw and sketch from a database of bullet dimensions and style parameters. The software is still under development as more features are being added and refined.

Inserted are images of the Data Entry Page, a dimension sketch and a parameter printout of the software module.

Once the data for a particular bullet is entered into the database, the bullet record can then be selected to instantly either view or print various sizes and styles of bullet images and dimensions sketches.

A more detailed summary of what the software capabilities are can be viewed at the following link.

http://www.uslink.net/~tom1/draw/draw.htm

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




http://www.uslink.net/~tom1/draw/ScrSnapMain.gif

http://www.uslink.net/~tom1/draw/ScrSnapVariety.gif

http://www.uslink.net/~tom1/draw/Sketch_Module.gif

http://www.uslink.net/~tom1/draw/report.gif

[45 2.1]

Good synopsis and a nice looking program. I imagine several people would like to have that. It should satisfy most people.

I for one would like to know the alloy density in grams/cc for all the different alloys you listed.

Do you use a optical scanner or comparitor to derive existing boolit dimensions or what?

[Ranch Dog]

I'm looking forward to Tom's product being available. I've started to use his Precision Ballistics and Records (http://www.tmtpages.com/index.htm#BPCB) software and it's great to have a cast boolit guy design such programs. The Target Analysis page has helped me split a few hairs in load development giving me a great shooting load that I might have missed. The software is available as modules so you only need to purchase what works for you.... I've ended up buying it all! I've been using Shooting Lab, which is kind of a high end software program but it doesn't have some of the load development features that the TMT product has. This thread is about cast boolit design so I won't wander any further but do want to follow up with another thread about the program once my hunters are gone. The hunters are from out of State and didn't want to travel with firearms so they are using my rifles with loads developed with the software this week! A 35 Rem load and a 450 Marlin load.

[Tom Myers]

45 2.1

Here is an easy method to calculate the Specific Gravity of a bullet alloy in Grams per Cubic Centimeter.

This is the Algorithm to use:

S.G. = 55770 / ( %Lead x 49.16 + %Tin x 76.01 + %Ant. x 83.24 )

The Specific Gravities of the 3 common bullet alloy metals are:
Pure Lead = 11.345
Tin = 7.337
Antimony = 6.7

Multiply the percentage of each metal in the alloy by the following values:
Lead multiplier = 49.16 ( 7.337 x 6.7 )
Tin multiplier = 76.01 ( 11.345 x 6.7 )
Antimony multiplier = 83.24 ( 11.345 x 7.337 )

Now, divide the sum of those multiples into 55770 (7.337 x 6.7 x 11.345 x 100 )

Like so:

Nominal Wheel weight alloy proportions are:
95% lead
4.5% Antimony
0.5% tin

So,
Lead = 95% x 49.16 = 4670.02
Tin = 0.5% x 76.01 = 38.01
Antimony = 4.5% x 83.24 = 374.58
Sum of these = 5082.61
Dividing 55770 by sum 5082.61 = 10.9727 = the Specific Gravity of wheel weights

Or a 1 and 20 Tin + lead alloy:
1 / 21 = 0.0476 x 100 = 4.76% Tin and 95.24% Lead

Lead = 95.24% x 49.16 = 4682.00
Tin = 4.76% x 76.01 = 361.81
Antimony = 0.0% x 76.01 = 0.000
Sum of these = 5043.81
Divide 55770 by 5043.71 = 11.0571 = the S.G. of a 1:20 Alloy

For those who do not care to do the math, here is a listing of some alloy Specific Gravities in Grams per Cubic Centimeter

Tin/Lead Alloys
1/41 = 11.1958
1/40 = 11.1922
1/31 = 11.1485
1/30 = 11.1421
1/25 = 11.1024
1/21 = 11.0574
1/20 = 11.0434
1/16 = 10.9704
1/10 = 10.7574

Lyman #2 = 10.683
Linotype = 10.383
Monotype = 9.670
Wheel weights = 11.0100 to 10.973 just average them out to 11.000

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

[45 2.1]

Thanks!:mrgreen:

[Ranch Dog]

Likewise, thanks Tom

[shooter93]

Thanks....and what I did mean was Draw...not design...a slip of the keys

[Tom Myers]

I had made a couple of math errors on the Specific Gravity Post but they are fixed now.

Thanks 45 2.1, for pointing them out to me.

I was proofing the post when the snow plow guy came and was so excited about busting out of here after being drifted in that I forgot to finish the proof reading of the post.

Tom Myers
Precision Ballistics and Records (http://www.uslink.net/%7Etom1/)

[truckjohn]

45 2.1

How do you use Autocad to calculate the CG and Center of Pressure for your boolit designs?

I can do AutoCad myself -- just a little slow..... it is the part about "Will it actually fly right in real life" that has me stumped.

Thanks

John