Hey outdoorfan, the figure is from Lee, but is very close to true.
I am interested in your 190 grain load and we have talked a little bit before about your load. I don't doubt your BC figures and I think it is awesome that you proved that Rossis will stabilize that heavy of a bullet when cast with a soft alloy. But, one thing to keep in mind is that you are running a soft alloy and therefore your bullet slumps upon firing. This changes the ogive and BC because more of your nose sets back. Your front driving band is surely growing and the ogive is getting shorter.
Your nose is approximately .3 inches long sticking out of the case. You are seeing a lower BC with softer alloy because your approximately .1 inch driving band and .2 inch ogive are changing under acceleration to .2 inch driving band and .1 inch ogive. Basically WFN bullets with soft alloy turn into "ogival wadcutters" when shot at high pressure with slower powders. I will upload some pics of recovered bullets of harder and softer alloys where we will be able to see just how far back a bullet nose slumps at 35k psi. I have some nice examples of the ranch dog 135-rf and the Lee 158-rf.
If you were to run hardball alloy I bet you would have 75-100 fps more at 200 yards. From memory I remember you saying you are about 1800 fps at the muzzle and 1160 fps at 200 yards. On my calculator this calculates at .18 BC. But with hardball the lube grooves won't completely disappear, and that means with hardball your bullet will be longer when it leaves the muzzle. You may see loss of stability if you are borderline stable now because a longer bullet at the same weight needs a faster twist.
My water dropped 4%Sb alloy probably comes up to 18-20 BHN from 410 degrees. Therefore the bullet after being fired, and especially the ogive of the bullet, looks relatively unchanged compared to when I had used a softer alloy.
Attachment 215930Attachment 215931
These green 158s are BHN 9 range scrap fired at about 20k psi. Notice how much ogive is lost already. The traditional lube 158 is wheel weight alloy over 14.5 grains of 2400. Notice that it slumped more than the range scrap at 38 +p pressures. The green 135s are 2/2/96 alloy shot out of a 6" revolver. Not even my hot load of 2400. Just 9 grains of power pistol at 28-33k psi. Imagine how dramatically different they would look with 17.7 grains of 2400 and 10 more inches of barrel to accelerate and slump in. The traditional lube 135 was water dropped wheel weights and it slumped a little less than the 2/2/96 even though it was shot with the full power 2400 load. The more they slump, the worse the BC. Harder bullets out of the same mold will always have a better BC. I will have to dig around and find the harder bullets later tonight.