Recent content by TiroFijo

JBM, could you please tell me this number to "translate" into my system: drop at 100 yds, with the barrel parallel to the ground (no elevation dialed in), with sight height = zero; or how much elevation you need for a 100 yds zero, stating the SH you use. TIA jimm, why do we spent time in stuff...

JBM, Gustavo, we're in a crossfire Sorry, JBM, we are latin! Drop at 100 yds is just the drop with the barrel parallel to the ground, with sight height = zero.

JBM, not Gustavo, but: the "drop" number in your example is not "real drop" (vertical distance between the bullet and its line of departure) in my nomenclature, but the "bullet path" ((height of the bullet's point of impact in relation to sight line), and it is related to it by the following...

JBM, Sorry about the numbers in my example, it should read meters instead of yards BTW, this "modified JBM" http://www.mega.nu:8080/traj.html that uses several G1 BC's like the Infinity has almost identical results.

JBM, I believe the basic formulas I posted are widely used, perhaps with a different twist or additional refinements. When Gustavo, our dutch friend Jeroen (the author of the article in the link I posted) and I were trying to find out more about canting, I wrote to Bill McDonald of Sierra, and...

The basic formulas we are using are: horizontal projection: X = drop*sin ß vertical projection: Y = drop*(1 - cos ß) ß = cant angle I think these formulas should be pretty accurate for the small angles we are discussing, normal cant in LR shooting should be 6º or less. The sight height...

FWIW, I have a couple of friends that shoot great groups with factory Federal Gold, 69 SMK @ 3000 fps, out of 1-10" 24" barrels, AR15 Olympic ultramtch uppers.

Trader, once you have identical BCs then it does not matter what your bullet is made of. Blaine, that is an interesting system (...and less work than what I do, matching the trajectory at a few points) but this is not as accurate as the other system, because you have only two points in the...

jbubb: In std. cond. the 190 SMK @ 3000 fps needs about 26.5 MOA elevation to get to 1000 yds from your 100 yds zero. BUT you have to add the about 3.6-4.0 MOA elevation needed to zero at 100 yds (depending on your scope height). So your scope needs about 30.5 MOA to get to 1000, and this is...

Blaine and JBM: I use the Sierra Infinity program. It is simply the one I have, and it agrees quite well with Sierra bullets. When I have to "fudge" to fit my data I play only with the BCs until I get the predicted come ups to agree with the field tested ones. I try to record accurately the...

Brad, send me an e-mail if you are interested and I'll try to contact you with HBC.

Brad, I was just quoting these results from a friend. I will send him a mail to your site so you two can compare notes.

I of course (and humbly) agree with JBM above posts. On the question of which drag curve fits best a certain bullet (IF you have the correct BC data to use other than the G1 function) I've asked about this to a gentleman (HBC) that frequents www.benchrest.com and has the appropriate equipment...

Thanks JBM, that makes sense. Do you perhaps remember the site where there is a duplicate of your trajectory program adapter to imput several BC at different velocity ranges? Now, does anybody thinks you are going to find a better "fit" than the G1 fuction for the 190 SMK (only 3.4% BC...

Brent, I really don't know about the algorythims. The G1 funtion is the one the Infinity uses, BUT the program can use the different BCs at different velocities, most programs cannot. There is somewhere in the web a version of the JBM ballistics program altered to use different BC at different...