I bought a bullet design program about a year ago and I have found it to be very accurate in calculating mathematical ballistic coefficients and I thought it might help people on this forum to make choices and decisions of what they may want to try.

My main area of interest is spitzers and most of these will be in that area but, not all. 

I will start with the Ideal/Lyman molds that I have and then go on to target molds that I own, as well as bullets out of molds that I have obtained from friends.

Frank

Very nice. What is the program name and where did you purchase? Thanks.

Mike,
All that I can tell you right now is, Lymans # 4, Cast Bullet Manual, lists the 257420 at a BC of .129 and the 319247 at a BC of.208. 

One thing that you have to remember about bullet shapes and BC's is that velocity can make a very big difference. i.e. flat nosed and round nose bullets generally have a higher BC at lower velocities <1200 fps and extremely sharpe points give higher BC's at over 22-2400 fps. 

If you can look on page 98 of the 46th Lyman reloading manual it shows the differances in BC's for different velocitys of the same cast bullets. I believe Sierra give simular info on their jacketed bullets.

I don't know what velocity that the BC's are calulated at in this program but, you can use it to see what happens with the change in bullet shape and make comparisons to other bullets. 

I have two other programs that calulate BC and this one compares well with them. But, only velocity differances over a given distance, as gaged by caliberated chronographs will give the actual BC and you have to factor in air dencity on any given day along with that. 

In the end it is just a tool to be used in designing bullets with the hope of reducing wind drift. BC never won a match all by itself

Frank

Frank- I've tested just about every conceivable spitzer design cast bullet, many times the BC's of the bullet design software do not come close to the actual BC's determined by actual ballistic testing. Most software programs assume that the bullet is stable for its entire travel to the target, this is NEVER the case (The Bullets Flight by FW Mann), therefore the BC's tend to be higher than actual test firing, this is especially true in the case of the 100 and 200 yard ranges fired by schuetzen rifles. For instance the software of your bullet design program is for longer ranges per BPCR shooting. What my ballistic system allows me to do is find the optimum stability velocity for each bullet/rifling twist combination.
Regards-
Barry

Chris- I've noticed the bump/slump also with smokeless powder loads and I suspect that some spitzer designs  may also allow the larger ogive radius noses to have a tendency to slump off center due to rotational acceleration while confined in their travel down the barrel. Remember that BC is only an indicator of a bullets efficiency (time to target) and not an indicator of its consistent accuracy at any given range. Currently I believe a 5r ogive to be about optimum for efficiency and structural strength.  Prior to 1978 spitzers were rarely, if ever, used in ASSRA matches, with all the testing I've done over the past 10 years I still believe a flat nose bullet has an edge in accuracy for calm condition shooting. An accurate, higher BC spitzer has the advantage with its reduced wind drift. The spitzer style bullets became popular after the first Coors Match in 1982 and 200 yard shooting, prior to then most SS matches were at 100 yards. 
Barry

More Ideal/Lymans

Even more

JLouis wrote on Apr 30^th, 2013 at 6:44pm:


So far my program has shown it's self to be very conservative. I talked to Barry and he had results for my borrowed 33 cal Ron Long bullet that was shot in the Modesto match by it's owner. The program predicted a BC of .395 and in actual firing at 200 yards the BC was .44. With another less areodynamic bullet my program predicted a BC of .282 and that bullets actual 200 yard BC was .32 and change. So, it maybe inaccurate but, in the direction at I preffer

Frank