How wide is your load or node window?

[in2deep]

In general when you find a sweetspot for your load how wide is the powder charge window in 1/10 ths of a grain till the point of aim changes?

 

[camac]

This is a bit of a "how long is a piece of string question". Dependant on cartridge and which "node" you are hitting. Also at what range you are testing. Some nodes will stretch over 3 * 0.5 gr imcrements (or more) at 100yds and cover over 150fps variation and these are often looked for but not always found.. An accuracy node at 100 yards that may cover 150fps certainly won't give the same results at 1000 due to variance in velocity. It may still be accurate at 1000 but you have to control the powder (and velocity) variation. The further out you go the smaller the "window" for vertical spread.

If you want an answer a little more specific then perhaps a few more details such as cartridge, powder, primer, projectile etc.

 

[bheadboy]

i personally have found 2.5% powder reduction to 5% depending on the case and how much i am willing to give up

on the upside depends on the load that shoots, if max, then "0"+ , if under max + 2.5% but not above max.

Bob

 

[in2deep]

I guess it was a generic question but likely too vague so basically pertaining to loading 6 BR cases with about 30 grains of Varget and 105 bullets. Just curious after studying the ladder test regimes it seems that there can be a considerable powder charge range that gives consistent accuracy/point of aim results and that finding an area with a wide range seems to offer some lattitude or a buffer as opposed to loading on a small specific node that can be difficult to maintain.

 

[camac]

The big advantage to finding a "wide range" is in changing temperature conditions. Even though your shell to shell variation might be low, there can be a significant shift in weather conditions. Hence a wide "node" can be very handy and can save taking the loading gear to the range all the time. Two examples of my nodes at 6BR range are 300m 80 gr likes 30.7 -32.0 gr varget and 3040 to 3120 fps. The 105 gr (300-600m) likes 29.3-30.5 Varget and 2850-2930 fps. But at 600m you will start to see sinificant vertical spread if velocity ES or powder charge varies from shell to shell so I still ensure powder is measured to the 0.1gr and load in the middle of this velocity range - powder charge can vary slightly with batch. I would recommend you think of it as "velocity" range rather than powder charge though.