Can someone explain "Mapping" ?

[G37]

Hey all,

I have a vague idea as to what mapping is... but would like a clear explanation.
As far as I understand, it is used when pushing a load... one moves in small increments (e.g. .2gr at a time) then looks for a variation that is inconsistent with the previous consistent increases in velocity.

But what variation occurs?

~Cheers

 

[martinbns]

Variations in velocity. The theory (I Think) is that the when the sweet spot load is found the velocity spreads will tighten noticably, theoretically giving better accuracy potential.

 

[roberti11]

Hey all,

I have a vague idea as to what mapping is... but would like a clear explanation.
As far as I understand, it is used when pushing a load... one moves in small increments (e.g. .2gr at a time) then looks for a variation that is inconsistent with the previous consistent increases in velocity.

But what variation occurs?

~Cheers

The most important thing you are looking for is to find the 'harmonic node' for your bbl, with the bullet, powder, case and primer you are using. When you fire, a shock wave travels thru the steel bbl, and sets up a standing wave as shown below. You want to find the fastest load with the least vertical spread. After I do that at 100 yards, I further tweak it at 300 yards by making small changes to the load, and COL. At 300 yards I am not concerned with horizontal spread, unless it is extreme, I am looking only at the vertical dispersion.