Nick,
I was also experiencing real 'dirty' performance with 5.2gr of HP38, but when I reduced the load to 4.0gr it ran way cleaner.
I feared it might be worse, but got a pleasant surprise.
I currently have 8lbs. of HP38, about 1300 185gr RNFP bullets, and 2000 good cases.
For now, I am going to find the spring this load runs OK on,
and go,go,go.