Slingshots Forum banner

Comparing ammo drop at longer ranges

911 Views 16 Replies 11 Participants Last post by  karaolos
I will try to be as concise as possible - apologies for the long winded theoretical question...

Lets say we have a bandset that shoots 6mm steel at 250fps, and also shoots 8mm steel at 200fps. I think this is reasonable...

The faster traveling, lighter ball will loose less height at least at shorter ranges - but, because it's lighter and traveling faster, it looses more of its speed as it travels.

The question is, at how long a range is the drop of the heavier 8mm ball (that is initially traveling slower) equal to the drop of the lighter 6mm ball?

Alternatively, is there a simple trajectory-plotting software for spherical objects?

I'm trying to figure out if this distance has practical application in ammo choice - given a bandset of desirable draw weight.

Thank you!
1 - 1 of 17 Posts
Question: When shooting at a distance, how much does my ammo slow down?
Answer: We've actually done quite a few tests on this very subject.
When comparing ammo of the same diameter, the denser it is the less it slows down due to air resistance... Which means, i.e. that if you're standing next to a chrony and shoot a .44 lead ball (123 grains) at 220 fps.... then step back to 10 meters and shoot again, the ball will register about 218 fps... whereas a 7/16" steel ball (84 grains, .437 diameter) of about the same diameter as the .44, will start at about 240 fps and at 10 meters will register at about 230 fps.
So in 10 meters of travel a .44 lead ball drops in velocity about 2 fps, a steel ball of the same diameter drops about 9-12 fps (depending on air density, ie. elevation)... and a 7/16" marble (35 grains) drops about 20-30 fps (air density) per 10 meters.
At 20 meters the dropped fps values are almost exactly doubled.

What this tells us is that so long as you have a good "fps/power cushion" built into your setup.... like for example, it takes 200 fps to make sure of a clean kill on a rabbit using .44 lead... then if your starting fps is 220, you will still have enough "left in the tank" to be deadly out to 100 meters, so long as you can shoot accurately enough at that distance.
If you wanted to match the power output of the .44 lead with the 7/16" steel balls, your maximum range is about 20 meters.
The 7/16" marbles never would match even the steel balls and would have to start at close to 300 fps to even be minimally deadly at 10 meters. And at 20 meters it would be a fluke shot if they did any real damage on a rabbit or squirrel sized animal.
See less See more
  • Like
Reactions: 3
1 - 1 of 17 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.