OK, the Fanciful Title is to DRAMATIZE. This thread may need all the help it can get.
Don't we all do some "extrapolating", when deciding on a load? I certainly do.
I may not, usually do not have data for the Exact components I hope to use. I may use data for a hornady bullet for a Speer bullet of the same weight, or perhaps it's a Speer bullet for a Sierra bullet load.
Then, there is the powder charge to decide on for the starting load. What are the charge weights for that bullet weight in all the manuals or data you have, or enough of them. OOOOh but not Barnes, because they different. No give to pure copper, and more friction?
If this charge is given for 145 grain bullets, then should be safe for 140s?? OR the other direction, OK for 150s??
What about Sierra, and Speer again. Sierras, with BT and a blunt ogive. Speer with a Flat base, and a sharper ogive.
Rem. primers in the Data, but I use CCI. Mag. primers, or Regular? Data different but component data is also different to some degree. Should you use the same OALs as in the Data, with your different rifle chamber.
Who needs to handload? Just use FLs.
I hope you can see what I mean. But what are the rules for you? How far do you go, in extrapolating. Do you have Do's and Don't's?
Things you don't extrapolate on? How SAFE is extrapolating a little versus following the data to the letter?
What are your ideas and opinions on the whole idea of extrapolating?
Smitty of the North