This generally results in my going back to the range with new loads at 0.1 gr increments but only maybe 4-5 loads. I do 5 round loads of these and shoot them at 300 still with the chrono. After that I toy with the distance to the lands a bit if I have room in the mag. On most rifles, this will get you under 0.5 moa with SD's that work well past 1,000 yds.
See attached photo for homemade spreadsheet. I took the information from this spreadsheet and loaded a new set of rounds at 28.0-28.4 for further checking. Note that this was done using a Chargemaster Lite, which seems to only be capable of delivering mid to high single digit SD's. If I check them by hand on a better scale I can generally cut the SD's of most loads by about 4-5 fps, but for most of my shooting the Chargemaster is fine.
PS: Do not use my numbers. This is from an oddball .224 Grendel AR
This place is American parts and people just down the road from me.
They make very good quality for a reasonable price.
You can also configure one a little to what you want.
You will have to replace the trigger. In any brand.
Another great company is, Bravo machine company. (I owned one of theirs for 10 yrs. or more)
This company is top notch for quality and price, you will never hear a bad word about them.
3 shots, is usually the group and 5 shots is how good you are.
In load development, if your confident in your abilities then in
3 shots you will see what the load looks like, if not sure of yourself
then 4 is much better. At 3 shots, if you pull one, then you only have
2 shots and that's isn't enough to see what a group is doing.
Load your different loads in no more than .3g of powder difference.
If you go .5 you might miss a node or not see if it was coming in or going away.
You don't have to get for crazy for distance either. The farther you go, the more
outside influences will throw the groups off.
Once you have it narrowed down, then go long and fine tune it.