A gun showing preference for a particular powder is not at all uncommon. Many times it is tied to particular bullets and load levels, but sometimes it's across the board. Unfortunately, the only way to find out if your gun has such a preference is to try different powders. I've had good luck with Universal, but I can't say I've seen any accuracy difference between it and Unique in mid-range to +P level loads for the 1911; nor in the .44 Special. I've not compared them in any of the various thirty-six caliber handguns I have.
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