OK, Where to start. Well, Nick compares Silhouette to AA#5. As near as I recall in my readings, I think most of those articles indicate that Winchester transferred their rights to WAP (Winchester Action Pistol) which has returned to production as Ramshot Silhouette. One indicator that makes me inclined to like those stories is that the old Win WAP load data and the early Ramshot Silhouette load data are not just similiar, they are identical.
The Win WAP seems to be credited as the powder used to develop the 40 S&W and the Win 9x23. One of the earlier articles I have seen indicates that the Win folk advised against using the powder for revolver cartridges since it was designed to burn hot and release large gas volumes, sorta like AutoComp, which I think Win has replaced WAP with. That translates to potential gas etching/cutting near the cylinder gap. But it should be appropriate for high pressure pistol cartridges.
The above reasoning was what lead me to start experimenting with Silhouette. One candidate goal was close to Bestknife's opening post above. I wanted to obtain a generic load for carbine types in 9mm. Accuracy was not the goal, reliable cycling was. I will leave out the chapter on what I go through to determining the safe load test ranges, but I will say that once I believe I have a safe (non-plus P) test range, the added factor of test guns that are +P capable gives me an extra safety margin, since I try to avoid +P loading for any caliber. I was also curious about the use of hollow base bullets by some manufacturers and why that might be useful. In that respect, I ended up with two primary bullets for test. Montana Gold 124 gr. FMJ flat base and Winchester 115 gr. hollow base. Laid side by side, they have matching profiles.
Test carbines were Uzi, M-11 carbine, and yes folks, a High Point 9mm carbine. Long story short, my generic carbine loads are 5.5 gr silhouette under a 115 gr. Win hollow base, and 5.5 gr silhouette under a 124 gr. Montana Gold FMJ. Also since Power pistol has been mentioned, that is also a generic carbine load as 6.3 gr. Power Pistol under the 115 gr. Win Hollow Base FMJ and 6.3 gr. Power Pistol under the Montana Gold 124 gr. FMJ.
You read that right, same powder charges used for different weight bullets, and ALL have the same OAL of 1.145 .
As a side note, these loads are what I would call about mid range for most loading charts, function very well in the carbines I tested (which are basically blow-back types), and have also functioned well in a Rock Island 1911 style 9mm, A glock 19, and a few I do not recall the types. I have not yet tested these for velocity.
Here is one I have tested recently in 45 ACP.
185 gr. MGJHP with 8.3 gr. Silhouette avg vel = 1043, extreme spread (10 rounds) 71, Std Dev. 25.
Same bullet, 8.3 gr. True Blue, avg vel 988, ex spread 65, std dev. 20.
Same bullet, 8.3 gr. Power Pistol, avg vel 1070, ex spread 64, std dev. 21.
Test gun was Colt Combat Elite 45 acp and all test loads were OAL of 1.190.
I am currently testing Silhouette in 380 auto but initial chrony trials with it are giving disappointing std dev. numbers and I have no operating theory as to why that is. Function is great though.