.50 cal ballistics chart? I want to learn more!

[thatoneguy]

Im new to BP rifles. got my .50 call built. but was wondering if anyone had a ballistics chart for a .50 cal patch and ball .490 diameter .177 grain out of a rifle with 1:66 twist with a 36" barrel.
im thinking of using pyrodex RS and wanted to know the muzzle velocity and energy loss the further it goes out. now i know its not a 30-06, but im sure almost the same concepts apply. any help would be appreciated! :idunno:
if someone could link a chart or something i would love that! all i find is for 1:24 or other twist barrels.

 

[coloradoclyde]

:shocked2: How much powder are you shooting?

 

[Semisane]

This should give you some idea.

 

[Khufu]

balistics for round balls Try this, should answer all youe questions

 

[Khufu]

though my .490 lead balls weigh about 181.5 gr, I assume he means ball weight. (I hope)

 

[coloradoclyde]

This should give you some idea.

Notice how little increasing the powder charge affects bullet drop at 100 yards....

 

[coloradoclyde]

OH! he meant ball weight

 

[thatoneguy]

thanks everyone! I'm excited to start seeing how all this comes together for me! got more material to go over. but a quick question about the chart what does the minus have to do in relation to the plus on the drop sections?

 

[Khufu]

ball is above line of sights

 

[thatoneguy]

ohh! that makes sense haha thanks!

 

[Walks with fire]

My 1/70 twist GM .50 does a little over 2000 fps with 100 grain of Goex 3f. It's 1.2 high at 50 and on at 100 yards.

 

[Khufu]

in orfer to be on at 100 yds and 1.2 high at 50 yds a .490 ball would need to travel 2650 fps ... I want some of that powder!

 

[coloradoclyde]

Barrel length and sight height makes the difference something that is not always factored in.

 

[Khufu]

I set sight height to 1" and MV is MV no matter how long the barrel the other 2 factors I guessed, temp I set to 70 deg colder makes the ball slow faster, and altitude which I set at sea level, and the higher the less it slows, but those are not enough to move trajectory enough to change assumed MV more than +/- 50 fps

 

[Khufu]

setting altitude to 3000' (elevation shows Mt Davis, Pa. at 3218 feet and low areas at 918 feet)
setting temp to 50 deg. still need 2550 fps to be zeroed at 100 yards and be 1.2" high at 50 yards.

 

[coloradoclyde]

Every ballistic program has limitations within the algorithm.
How the barrel lays in the stock can affect accuracy down range but the biggest factor is still the guy behind the trigger.

You are comparing your computer data to another persons real data.

 

[coloradoclyde]

Another often overlooked factor is how different people achieve their sight picture and how that sight picture changes with distance.

That's why scopes are so popular. Most people cant maintain a sight picture.

 

[Khufu]

the balistics calculator aligh well with my chronographed shots, and there is a weather station a half mile from the range where I get temp, barametric pressure and wind velocity and direction. elevation at the range is just over a mile. I zero at 75 yards and computer says drop at 100 yards should be 2.6" and I measured it at 2 5/8 inches to center of group a difference of .025". it is spot on. (my .490 mold is worn out and casts after ball mill .494 and weighs about 181.5, and I accunted for that) my measured MV was average 1948 fps (5 shot string average)with 100 gr ffg goex from a 32" barrel (Range temp 86 deg). percussion ignition (CCI #11).

 

[Walks with fire]

I must be flinching. LOL

 

[Loyalist Dave]

Ballistics charts give you a nice ball park idea of what your round ball is doing, but until you actually chronograph your load, you may be surprised. Big difference between a 32" barrel caplock, and a 42" barrel flinter for example. Then you have the patch seal, the granulation of the powder, the size of the touch hole vs. the pressure loss.

Then you have Khufu who is shooting and chronographing at a mile up so thinner air, in low humidity by being in Albuquerque..., take his rifle to the Shenandoah Valley on a very hot day with 100% humidity, and his results will skew....though probably not too much.

LD