FWIW that Pinnacle powder sold by Goes is made for them by American Pioneer Powder (APP). I have tried APP extensively in my percussion arms, specifically as it works fantastic with dry-lube patches ala the Dwight Shultz system. I used to use this method for the winter snowshoe/muzzleloading rifle biathlons, before I bought my 1st flintlock smoothbore.
At BEST, I found that APP was capable of reliable ignition (#11 magnum caps) and tight groups in temps down to 8-degrees (wasn't out in any colder weather
). APP does NOT build-up in the bore at all! I once posted photos on the MZL forums of a wiping patch after 1-shot and then after 30-shots and they look the same. Even with dry-lubed patches in ccccccold weather, I could shoot 30 or more shots with zero efforts loading (coned muzzles) as the unburnt powder doesn't cake or build-up or anything else bad, like leaving a heavy carbon or 'crud ring' ahead of the combustion area as does Triple-7 powder.
The barrel would also clean up in 5 patches or less using Butch's Black Powder cleaning solvent, which to me is the BEST cleaning solvent out there for BP arms, if you need to use something besides water. I now use water only in my flint smoothie, followed by a preservative oil (Ballistol).
At WORST, the APP powder is not designed for use in flintlocks and I believe you would need to use a duplex charge, by putting 10 grains or so of real BP down the barrel first before the APP rest of load. I had frequent failures to fire or slow firings until I switched to magnum caps in percussion arms.
Off-topic, but I know people that do the duplex loading, but that is because real BP is tough to buy here in Mass, while Pyrodex and all the other fake BP powders can be had at every sport shop, so some buddies of mine do the duplex loading just to keep them shooting. And yes ... we know all about groups buys, just remember there are tougher Fire regulations on the storage of BP than other powder types and these guys live in small apartments and don't have out-building where they can keep a cache of powder.At WORST , APP powder is highly INCONSISTENT! One bottle I had was fantastic! With the next, the same load sounded like a squib load and would not group and was was off the same point of aim as the other. This happended to my brother and another friend and they have switched back to Pyrodex for their side-locks in their hunting arms (Yes, I tried to switch them to real BP, but to no avail).
At WORST , APP powder is very underpowered, being 100-200 FPS off the velocity for the same loading using Pyrodex or real BP. APP is also highly hydroscopic (attacts water) so you really need to be careful and diligent when opening it for use. They even recommend you don't put any powder back into the main bottle, so as not to contaminate the rest.
My summary of experience ...
forget about APP powder ... and go buy some real black powder!