I think you mean .40 to 9mm conversion...I have one but not for the Gen4 pistol...no issues in mine with 124GR ammunition...mostly Speer Gold Dot and Speer Lawman...I had tried some cheap Aguila in 115GR and had 2 in 100 FTRB that just a touch to the slide cured...but that was enough for me not to buy any more for my G23 wanna be G19...
****G17**G21 Gen4**G26 Gen4**G30S****
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