allaroundhunter
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Not for the bullet that you are looking at...
Long range shooting formula, ballisitc coeficient etc
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Not for the bullet that you are looking at...
MtnCreek
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MCgunner
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Uh, BC affects time to distance. Time affects drop via Newtonian physics, D=1/2gT^2. Therefore yes, BC certainly DOES affect drop via affecting velocity which gives you time to distance from which Newton's laws rule.
Went shooting today, borrowed a friends savage axis .308 and his ballistic calculator I can do hold over and the "kentucky windage" with the mil dot scope but I still have no idea how to use the turrents on the scope. We only had about 30mins and didnt know the exact range, it was around 700 maybe a little more or less. I guess I'll figure out how to use the turrents when I pick up a scope for my ar. I see what you guys meant when you said I would just have to try shooting at thoes ranges. I hit 3 out of 5 targets with 3 shots each. targets were at 200 yards (exact measured) 300 375 500 and then 700 After the first target it wasn't exact (we paced it off)
Could someone tell me how the mil dot reticle works with MOA turrent knobs??
Could someone tell me how the mil dot reticle works with MOA turrent knobs??
45_auto
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Go here, do the classrooms, then do the demo. They have one for MOA turrets and one for MIL turrets. Good explanation, demo, and practice in how to use them.
http://www.shooterready.com/lrsdemo.html
Then buy it and practice until the calculations become second nature. It'll cost you less than a box of bullets.
At that point you'll be ready to go out into the real world and find out that there's a lot more to it then knowing how to turn the scope knobs (by the way, they're called "turrets", not "turrents").
http://www.shooterready.com/lrsdemo.html
Then buy it and practice until the calculations become second nature. It'll cost you less than a box of bullets.
At that point you'll be ready to go out into the real world and find out that there's a lot more to it then knowing how to turn the scope knobs (by the way, they're called "turrets", not "turrents").
BullfrogKen
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allaroundhunter
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It really isn't that difficult. It is a good thing to get a handle on before you try pushing the limits of that 9x39mm round...
Kernel
Member
No. I see what your saying but it’s not quit right. Notice BC does not appear in that equation you wrote? All bullets have a unique BC, but they all drop at the same rate. By your logic they should each have a unique drop rate too, and we know that’s not true. Newton’s laws and all.
BC let's you determine velocity. That's it. With velocity over a known distance you can solve for time. It takes the OP’s semi-mythical bullet 0.647 sec to travel 200 yds (X axis).
With that known time you can determine drop AT THAT DISTANCE (the “AT THAT DISTANCE” is the key concept here). At 0.647 sec the bullet has dropped 38.5 inches (Y axis LOS). I don't need to know BC to know when a bullet has dropped 38.5 inches. Every bullet ever made takes 0.647 of a second to drop 38.5 inches.
(For simplicity I’m talking LOS as per my earlier assumptions with the scope 2-inches over the bore. Two inches is standard for semi-mythical suppressed Russian machine-pistols).
No, it let's you calculate the time of flight based on initial velocity, drag coefficient and altitude density. It allows the calculation of acceleration on bullet caused by drag.
Another factor that complicates things is that the BC of some bullets change as it's velocity changes
Kernel
Member
MistWolf,
Your right. I talked about “speed” (velocity) because it’s something everyone understands. For example, muzzle velocity is something every shooter knows something about.
I didn’t want to bring up the concept of “acceleration” in the earlier discuss because it complicates things which leads to eyes glassing over. Nobody’s ever turned to a ballistic table looking for their favorite load’s acceleration at 100, 200, and 300 yards.
And your right about BC as well, except it’s not “some bullets”. It’s every bullet. BC can be a hard number to pin down since in the real world it’s always changing. Some bullet mfgrs will even list three BCs for each bullet. One for subsonic, one for transonic, and one for supersonic. Even then they’re just approximations. And those three numbers won’t even be close to each other.
Most ballistic equations will give good enough results, with in a faction of a inch, if you use the transonic or supersonic BC. For subsonic loads use a subsonic BC. It gets real interesting when you try to model the fight path of shot gun slugs and air rifle pellets. Though I don’t think anyone’s ever calculated the come-ups for a air gun pellet at 1000 yds, and then were able to verify it with real shots on target.
Your right. I talked about “speed” (velocity) because it’s something everyone understands. For example, muzzle velocity is something every shooter knows something about.
I didn’t want to bring up the concept of “acceleration” in the earlier discuss because it complicates things which leads to eyes glassing over. Nobody’s ever turned to a ballistic table looking for their favorite load’s acceleration at 100, 200, and 300 yards.
And your right about BC as well, except it’s not “some bullets”. It’s every bullet. BC can be a hard number to pin down since in the real world it’s always changing. Some bullet mfgrs will even list three BCs for each bullet. One for subsonic, one for transonic, and one for supersonic. Even then they’re just approximations. And those three numbers won’t even be close to each other.
Most ballistic equations will give good enough results, with in a faction of a inch, if you use the transonic or supersonic BC. For subsonic loads use a subsonic BC. It gets real interesting when you try to model the fight path of shot gun slugs and air rifle pellets. Though I don’t think anyone’s ever calculated the come-ups for a air gun pellet at 1000 yds, and then were able to verify it with real shots on target.
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