[Greenhorn Dave]

OK Math Wizards: here's one for you.

I like using the BTB External Ballistics Calculator in the Ballisticians Corner of this website.

It probably doesn't make a heck of a lot of difference for the short distances I shoot, but does anyone have a list of the Ballistic Coefficients for Beartooth Bullets? I am shooting 265 grain 44WFN and am entering a BC of 0.20 for that bullet.

What about the Drag Function? I just use the default G1, whatever that means.

If the BC and the DF are constant for each BTB, perhaps one of you Math Wizards can make a list for BTB to post on the site.

Thanks,
Dave

 

[Greenhorn Dave]

I've hit the wall.

Thank you, Jack. I just wanted to know and I do appreciate your reply. I failed nearly every math course I ever took in school, but I can use a framing square and calculate the volume for storage tanks and other stuff I need to get done.

I have been doing pretty well and having a lot of fun with a lot of the numbers and measurements in this shooting and handloading game. However, I believe I have now reached my limit. I have hit the wall.

I have thought about some of those things, including the changing BC when things are scaled up. I guess that falls under the laws of physics.!? I know from building boats that scaled-up displacement hulls will go faster than shorter ones of the same dimensions (don't ever expect to outrun an aircraft carrier with your racing canoe.) I bet a different law of physics applies to scaling up bullets, but there could be some parallel there. I will read the columns you suggest, then go happily back to the reloading bench and keep doing what I am doing. This is a great hobby!!

Sincerely, Dave

 

[Greenhorn Dave]

KciH -

Amazing!! I had no idea. I did check the Oehler link you put in your post. $1000 PLUS a laptop is a lot of $$$$, but I guess it is cheaper than renting a mathematician every time you go shooting.

I am not that extreme. My favorite gun is a short barrel 44 with open sights and I shot a full power 5 inch 30-shot group at 50 yards last month and I was so happy I think my smile stretched back to my ears. I know it impressed the guys next to me chipping away the target posts (like I did in the beginning) with their .22s @ 15 yards. Ah, the satisfaction of sticking with something until you get pretty good at it.

That said, I am way far from being good enough to need one of those Oehlers. As to safe pressures, I am still naive enough to believe the powder manufacturers max load recommendations.

I think I've pretty well decided that rather than buy more equipment, I'll just buy more powder and bullets and try to go shooting more often.

Dave

 

[Greenhorn Dave]

Since it is generally agreed that the 265 grain WFN Beartooth Bullet would be about .20, and the Sierra info states a range between .195 and .230 for the velocities at which I send those bullets downrange, I went to Beartooth's online External Ballistics program and ran 3 sets of numbers.

For all three sets I used the 265 grain weight, 1200 fps, left the G1 set where it is, used my open sight height of .85, set the temperatures etc at moderate, and entered a 60 yard zero which provides the best rise-and-fall average for the less-than-100 yards range I shoot in.

The only change in the three calculations was using .195 BC for one and .230 BC for the other and .5 BC for the third.

At 100 yards, which is near the end of the world for my skills, the .195 had dropped only .1 -- that's one-tenth of an inch -- lower than the .230 BC model. I can live with inaccuracies like that.

To push the envelope, I did a third try with the BC set at .5 and discovered only a .5 inch (half-inch) spread between the .195 and the .5 BC drop. I can still live with that. Mole hills for a guy who would be delighted if I could shoot a 6 inch group with open sights at 100 yards.

That said, when I get better I should pay attention to the BC. At an XKD (eXtreme Keith Distance) of 600 yards, the .195 would be thirty inches lower than the .230. The difference between the .195 and the .5 was 60 inches. So, if you are dealing in cannon-miles of distance you had better know what the BC is.

And now that I know all that, I can sleep better at night -- until the next question that puts me on the internet at wierd hours -- and I'll just go back to pouring the powder and pulling the trigger as I like to do.

Dave