Oh dear. Back to school!

[TenMetrePeter]

Cannot defy gravity even for a nanosecond. Thats why an angled flight becomes a parabola as soon as it leaves the barrel. Pellet will never be above the centre line of the barrel.

Furthermore you could hit the same target (ignoring air effects) by tilting the barrel above 45° by the same amount as the barrel was below 45°. Field gun vs howitzer.

Barrel 45° to horizontal will give maximum range. Same as javelin etc.

[Timmytree]

Cannot defy gravity even for a nanosecond. Thats why an angled flight becomes a parabola as soon as it leaves the barrel. Pellet will never be above the centre line of the barrel.

Furthermore you could hit the same target (ignoring air effects) by tilting the barrel above 45° by the same amount as the barrel was below 45°. Field gun vs howitzer.

Barrel 45° to horizontal will give maximum range. Same as javelin etc.

So my 11+ education wasn't wasted? No further education, no university but I'm right?

[TenMetrePeter]

Yes you're right. The diagram doesnt clearly show 2 zero points but there are 2 with a high scope.

With my 10m rifle the 10m target is before the highest point of the parabola so if I then shoot closer at 6 yards the pellet hits an inch low and has to be wound up 80 clicks.
With my pistol with low sightline the 6 yard and 10m targets correspond to the 2 zero points (by coincidence) and no adjustment is needed.

p.s. I did go to university and all you missed was 3 years of agony and 20 years of bad anxiety dreams. I wouldnt pay 40 grand for it now.

[Smudgerii]

An arc yes, due to sight position as stated. Does the pellet climb? No it does not. Does it immediately fall? No, not immediately as gravity has to ovecome the velocity if the projectile. The rate of fall is based on velocity, projectile weight and even your location on earth ( thats why the lauch space rickets in certain locations )

But hey go with what you like that way it’s easier to come on here and slag off a guy from another forum that you disagree with....

Ps. If you can’t defy gravity what are all those aeroplanes doing?

Pps. Two ‘zero points’ with every sighting set up high or low mounted, thats it if you have zeroed it... just physics

[wastrel]

well I`m lost, does the pellet rise (in it`s arc) or not? I thought it did!

[Timmytree]

well I`m lost, does the pellet rise (in it`s arc) or not? I thought it did!

No, fire a pellet with the barrel parallel to the ground and the pellet starts dropping the instant it leaves the barrel. It's only the scope pointing downwards that gives the illusion of a rising pellet. It's physically impossible for any projectile to rise above the line of the bore or barrel.

[TenMetrePeter]

An arc yes, due to sight position as stated. Does the pellet climb? No it does not. Does it immediately fall? No, not immediately as gravity has to ovecome the velocity if the projectile. The rate of fall is based on velocity, projectile weight and even your location on earth ( thats why the lauch space rickets in certain locations )

But hey go with what you like that way it’s easier to come on here and slag off a guy from another forum that you disagree with....

Ps. If you can’t defy gravity what are all those aeroplanes doing?

Pps. Two ‘zero points’ with every sighting set up high or low mounted, thats it if you have zeroed it... just physics

Smudgerii, just because it it going upwards does not mean it isnt accelerating downwards at the gravitational rate of 32 ft/sec/sec.
You need to understand the difference between velocity and acceleration. Believe me even though it is moving up it is accelerating down.
One advantage of studying applied maths at higher level.

Aeroplanes do not "defy" gravity as it is acting on them all the time They have a shaped wing where air moves faster above the wing than below and the difference in pressure balances out the force of gravity.
Even when spinning a diabolo does not have differential surfaces or pressures like a wing. It accelerates towards the ground at 32 ft/sec/sec even though it is travelling upwards for the first part of its travel.
The spin applies a stabilisation due to gyroscopic effect which can keep the pellet facing forwards but cannot reduce the rate of gravitational acceleration downwards.

Gravitational acceleration towards earth depends on altitude but not on velocity or weight (more correctly Mass because weight also changes with altitude) of the object. Heavier pellets drop more only because they take longer to get to the target and vertical velocity accelerates downwards for longer.

Hope this helps

ps Wastrel yes pellet does go up because the barrel points up but never above the centreline of the barrel, like Timmytree said.

[robertt]

Had the same heated discussion with an alledged ex army smallarms instructor who had obviously skipped a big paragraph in the tradjectory chapter.

An ex squaddy backed him up saying ' yes , I've watched tracers go up before they come down.'

They the would not accept the fact that a bullet drops when leaving the barrel and the rise and fall of the is an illusion created by the line of sight intersecting the tradjectory at 2 points.

There's a good article if you search Ballistics for Dummies but I couldn't attach link.

[eboswan]

Is this the one

http://www.rifleshootermag.com/shooting ... tics_0303/

[robertt]

Thats the one. Thanks