Another piece of bad information you got was that Ramshot owns Winchester. Winchester licensed the distribution of its powder brand to Hodgdon because it wanted out of that business. Ramshot is distributed by Western powders and has nothing to do with Winchester. So Hodgdon's site will have the best data for current production Winchester powders. Unfortunately, WAP isn't one of them. Who sells what isn't relevant to getting you load data, but the errors do make it sound like your information source is pretty confused. That would be OK if you weren't playing with gunpowder and putting yourself in danger of blowing up your gun and yourself by confusing the two powders.
What I can tell you is that WAP and Silhouette are both in the QuickLOAD database, and in that software it does appear they are extremely similar and that Silhouette load data will work for both powders. However, these loads are just about exactly half as much charge weight as you would use of 296.
For future reference, though, don't trust burn rate charts to identify similar powders. It worked out in this case, but often it does not. First, they are not very precise. I have found a burn rate chart that shows Bullseye is the fastest powder, another that says it is 3rd fastest, another that says it's 8th fastest, and yet another that says it's 15th fastest. And even if these were correct, burn rate is not enough information to pick a powder with. First, they make the comparison under just one standard set of conditions. In real guns burn rates often change places because the different characteristic burn curves behave differently under different pressures. For example, IMR 4895 is slower than IMR 4064 at low load pressures, but faster than IMR 4064 at higher load pressures. So you can see why you need to know what the powder will do in your actual cartridge. For another thing, different powders have different energy densities (Joules per gram) so that even if their burn rates behaved identically under all conditions, you would still need different charge weights of them to run at the same pressures.
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Last edited by Unclenick; June 19, 2012 at 10:08 PM.
Reason: typo fix