Yes it means my ammunition is constant. What I am chasing is a standard deviation (SD) of under 10 feet per second (fps).
The reason is that the speed of the bullet over a long flight time, say 1.7 seconds, means it will land in different places on a target. The faster it gets to the target the less it drops due to gravity.
Factory ammunition is not precision made and the SD varies greatly as there is variations in the powder load. There are also other variations like projectile seating depth and depth of the primer. With my rounds they are all identical.
If I do a ballistic calculation knowing my rounds have a 10 fps SD, and send the bullet it will hit in a certain spot, if I did the same calculation but the bullet was a factory load and was faster or slower in fps then it would hit in a different spot. The wind also affects a slower bullet more too. I never know how factory ammunition will behave.
So, having hand made rounds like mine means I can be accurate and precise when making them and the behave in more predictable ways. This is critical when the distance ranges out past say 300-400m.
To reach 1000m my .243 rounds are in flight for 1.98 seconds...It's a long time in the air and I need to know the bullet is going to act predictably...That 1.98 is based on a muzzle velocity of 2913fps...I know that because it's my own round.
A factory round might be sometimes 50-100fps slower...This makes a massive difference to the calculation, but I don't know what the speed is so can't adjust.
Does this make sense? I hope so.
Jep that makes sense and is exactly what I thought. First I thought that I would feel a bit uncomfortable shooting my own made ammunition but now I think it is the absolute opposite. As you never know where that bullet is coming from, how much powder is in it and so on.
How long you need for one bullet. Or how long did the 200 take.
You definitely need music for this kind of work. :)