Thanks for the advice.
The pistol is an ATI FX 4"
I decided to just go with the new fp. I took it the range and ran 200rds with no problems caused by the fp (dirty mags and one limp wristing). After another 200rds later this week I think I'll strap 'er on again. I may still play with the old fp to figure why the stoppages would continue even after the trimming.