You will need the #A10 adapter for the P15.https://donnyfl.com/products/p15-1-2-x-20-unf-adapter?_pos=1&_sid=9f13a1bbc&_ss=rI recommend the KOI .22 1/2x20 #S34. This will reduce pellet clipping while suppressing the P15.https://donnyfl.com/collections/ldc/products/1-22-x-7-inches-koi