So I recently ordered some 200gr TC hard cast from Rim Rock Bullets: https://rimrockbullets.com/xcart/-40-10mm-200-gr-tc-the-outdoorsman-per-500.html
I had some specific load data from Accurate using #9 and this bullet. In the process of deciding which bullet, I came across this mystery. The shape of the TC looks identical to the shape of many FP bullets like these 220gr from SNS Casting:http://www.snscasting.com/40-s-w-220-grain-flat-point-red-coated-500ct/
Or these from Badman Bullets:https://www.badmanbullets.com/OnlineStore/products.php?cat=40+200+Grain+FP
Here is what I thought a FP would look like:http://www.acmebullet.com/bullets-reloading-brass/40-10MM-Lead-Hard-Cast-Bullets?product_id=510
But maybe that should be called a LRN-FP? Like this:https://ammo.com/bullet-type/lead-round-nose-flat-point
Thoughts? Is they interchangeable when it comes to load data? Why different terms if its the same profile?
Reduce 10% and work up.
These types of differences in bullets of the same weight is the key reason for that rule. There are lots of actual variables that go into this, like usable case volume and bearing surface. In general a WFN design will have more lead in the nose than a traditional TC profile. More lead in the nose means both more usable case volume when the bullet is seated (less pressure due to boyles law) and less bearing surface between the bullet and the bore.
But, there is a lot of variability in TC and WFN designs, and often the description is not terribly informed as to what the terms actually mean. Or at least meant at one time.
So, reduce 10% and work up. If you hit velocity or have pressure signs, you have reached max.