How many of you guys have used used the manufactures stated ballistic coefficiency numbers wether it be G1 to G8 as drag functions and found them to be spot on.
Life is tuff.....its even tuffer when your stupid
{John Wayne}
I use manufacturers published BC but don't know if I have ever found one "spot on". For the most part, variations in velocity, altitude, temperature, etc. have been somewhat more "predictive" of performance of a bullet at distance than "correctness" their listed BC. Sierra is one of the few that use variations in BC relative to velocity in their published data....here is an example.
https://www.sierrabullets.com/store/...HPBT-MatchKing
Last edited by wbm; 05-02-2016 at 12:12 PM.
For me, Ive found berger,s ballistic coeff along with there calculators to be more on target. If I could afford Bergers for all my calibers?.....Id go Berger.
Life is tuff.....its even tuffer when your stupid
{John Wayne}
Glad you refreshed my memoryOriginally Posted by wbm
I remember seeing this. I looked it up while using there 150gr smk,s on my HS. I dialed up .417 due to my pill going 2815 for that particular load.
Have you personally used there there ball. coeff #s judged by the speeds of your pill and found them to be at least close if not spot on?
Life is tuff.....its even tuffer when your stupid
{John Wayne}
Bryan Litz has a couple books out where he has tested a lot of other manufactures bullets using the same method that he does for all of Bergers Bullets and he provides G7 values as well as averaged G1 values. I have found his numbers to be as close to spot on as one can get. Published BC's especially those by Nosler are way over inflatted. Most of the time Sierra is pretty darn close if you average the velocity band BC's to what Mr. Litz is getting. Hornady has gotten a lot better with their newer line of bullets with dopler testing and also provides G7 values for those as well. Nosler only tests at short range and at very high velocities which produces the highest numbers possible for advertising purposes. I have found as a general rule to take about 10% off of what Nosler publishes for a corrected BC to plug into my shooting solution and that gets me pretty close.
Agreed stomp. hornady bc #s for me have not agreed with my out come.
Life is tuff.....its even tuffer when your stupid
{John Wayne}
A lot plays the BC. I've G7 to be the most accurate for BTHP Match type bullets. I start with the manufacturer BC, get my velocity from a chrono. Then true my DOPE with actual drop data and adjust my velocity in my calculator.
One of the factors will most likely have to change in order to true your drop data. the easiest to adjust is velocity as 99% of people don't have the equipment or mathematic ability to recalculate the BC. If you're using G1 then you need to calculate the trajectory at multiple distances as the G1 function changes as velocity falls off.
I have not read Litz's books, but this is my basic understanding from self tests since I shoot at multiple locations ranging from 400ft above sea level to 5,000ft above sea level. Once I have true my data making atmospheric adjustments is pretty simple and for the most part spot on within 1000yds.
i do the same thing as LW...G1 is always way off unless entering multiple velocities and then still needs to be adjusted...G7 is always very close and then once you adjust your velocities to match your actual drops your set and using the G7 BCs its much easier to true up.
Yes. Quite a bit actually. I live at 7000 feet so obviously the performance of a given bullet is going to be enhanced. Last week I loaded the 107gr Sierra in 6.5mm to 3000fps and shot it to be dead on at 100. Then I moved to 300, 400, and 500. After measuring the drop at longer distances I plugged the data into JBM. After including bullet weight, velocity, BC, elevation, temperature, humidity even, the predicted results came out pretty close to "real life" results. But "spot on"?...Don't know but close enough.Have you personally used there there ball. coeff #s judged by the speeds of your pill and found them to be at least close if not spot on?
500yds is not far enough to tell in my experience. You need to go to at least 800-900yds or better if you can.
I can't see that far.
that's pretty close to what ive done.
Ive done my own math and have come up with a formula that's worked for me for years providing I have correct amount of drop at any given distance.
Last edited by eddiesindian; 05-02-2016 at 11:15 PM.
Agreed. from what I've noticed is that if I'm running my pills 2500-2600 which is what I usually run when shooting 400-800 yard matches, the BC numbers come into play at 600 ish. When I use my other rigs to go out to 1K, the BC numbers really come into play from 8 out past 1k due to the increased speeds 2800-2850ish.
Ive had trouble agreeing with Hornady 68gr HPBT in .224 BC numbers. Its a secant ogive which for me is odd that they show the BC numbers in a G1 and not G7. Ive converted to G7 and ran the numbers but my actual drop doesn't match. I gave in and just adjusted my come ups old school. Its the only pill Ive had trouble with. Ive researched via the world wide net and found others to have the same issues and they,ve come up with there own BC numbers.
Life is tuff.....its even tuffer when your stupid
{John Wayne}
For me Hornady bullets were inconsistent anyways. I won a couple matches with the 105AMAX, but when they get squirrely it gets ugly quick lol.
Never found Hornady bullets inconsistent but never shot the 105 AMAX. I have shot the 6mm 105 BTHP and match bullets in 6.5mm and .30 and they all shot very good and the BCs were on. I won, top 5 and top 10 a lot of matches with Hornady bullets since 2004. I run all my data a head of time and bring it to the match and using JBM I have never been off more than .2 mils at 1000, which is about 7",and mostly on or maybe .1mil but that can also be small shifts in environmental conditions. I have shot them farther as well in matches. Out to 1350 yards and they did what they should have. With their new Doppler radar numbers the BCs will hold much more true in the future.
Try shooting Bergers or Sierras. I went from being in the top 5 regularly to the top 3. .2Mils makes a difference in the wind. That's missing by a tenth or catching the edge of the target on a close wind call!
I shot my first 600 yard f-class match with 6mm Hornady 105 Bthp recently. I used the published data for come ups, since I didn't practice before hand and my first sighter was a 10.
I do use them. If I could afford it, I would use Bergers for all my calibers.... Be as it may, its only 4 different calibers but it adds up.
Life is tuff.....its even tuffer when your stupid
{John Wayne}
Have shot both. No difference in placing.
I was talking elevation of .2 mils. .2 mils of wind is about 1mph and if you can dope the wind to 1 mph at 1000 yards with no flags then you are **** good. Not many can.
The Hornady's do drop the same to 600yds. But the Sierra's and Bergers stay tighter passed that. I've shot the AMAX's out to 1375yds with good data, but you need to start them off 100fps faster than the Bergers or Sierra's to keep up after that. As for the topic of accurate drops, they were good for me until velocity feel off. I loved the 178 BTHP's in my 308 before I switched to the 6mm. They run very conisistent.
Off the subject, but my method of doping wind with the 6mm is guessing a range of about 3mph. so I might estimate it at 3-6mph or 12-15mph etc. Then I look at my data for wind at that distance to determine my degree of error based on the target size. i.e. if the target fits inside my degree of error, I'll hold in the middle of that range. If the target is smaller than that degree of error, I'll do my best to shoot with the wind or when it falls off time permitting.
My current range is real funny though because out to about 300yds the flags mean nothing. Passed 300yds every flag might be doing something different.
I've found the 115DTACs to be my bullet of choice in the end. For me it's done better then the Berger Hybrid or the 107 Sierra even running 100FPS slower.
So on this particular range doping to 1 mph is **** near impossible since you're shooting between the different winds. In the last few matches I've done this pretty well. But there are plenty of days where I miss a lot of targets by a 1/10 or so.
I found the Hornady bullets stay just as tight in accuracy and elevation as the Bergers and Sierras in similar weights. If you are just talking about the 105 AMAX then it's lower BC will allow the higher BC 6mms to shoot flatter and better in the wind but if you try the 105 HPBT I am betting you won't see the same.
I use a similar method for wind. It works well and if a miss then a quick follow up will take care of it. Doping wind at longer ranges is always best guess but it's best to make it an educated guess. Only place you can be 100% sure of the wind is your location and it's not as important there.
have the same issues with wind velocity and direction at the local military range I on occasion use. High banking berms to the left and right that are not located in same spots all the way out to 1K are problematic. And because of the flat dirt terrain, the mirage is terrible. Guys that are sporting high end glass even bark about the mirage.
Last edited by eddiesindian; 05-04-2016 at 10:19 AM.
Life is tuff.....its even tuffer when your stupid
{John Wayne}
Depends on the bullet design and shape. G1 was made for a much less aerodynamic projectile whereas G7 is for the more modern BTHP designs.
The only issue with G7 is that few manufacturers use it. Those that actually have G7 data of course dont have every projectile.
Edit: my load dope using G1 vs G7 for 223 to 1K yards was almost negligible anyway. Point, load dope that you verify will always be better than a mathematical model
Bill
Sent from my SCH-I545 using Tapatalk
Last edited by Bill C; 05-09-2016 at 04:12 PM.
A lot of this will also depend on what ballistics app/solver you use. Some seem to be more accurate than others. They're all EXTREMELY dependent on the info you put in, so if you don't put in good info, you won't get good data out. Your gun setup, your environmentals, your distances, all of these things.
Another very important one is making sure you scope is tracking like it should. Some will get more or less than .1 mil, or .25moa with each click. Doing a tall target test is the best way to find this out. Some apps will have a place you can adjust for this, because it's not something you can actually change in the scope, you just need to be able to account for it.
I personally use Shooter, and it works great. I shoot regularly out to 1100 yards using it. I've recently downloaded Trasol and want to play with that and see how it does, but I haven't messed with it much yet.
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