About the only justification for using 4227 ( an exceptionally slow powder) in ordinary .38 loads is that you can't get any other powder.

It is a classic mismatch in a stubby low-pressure load. Nothing is going to make it burn efficiently.

Bullseye, Unique, Red Dot, HP38/Win 231, 7625, and a dozen others would be better powders to use in your .38.....

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Science plus Art