My research has come up with a mounting system that is not generally compatible with the basic P-rod Dovetail system. The basic "fastfire" system is made more directly for the hand gun world with an cross section that is unique to that and other platforms. There might be an adapter out there, but, you will have to find it. considering another red dot that will work for you with a more adaptable base might be easier to find. Keep us posted.
UTG and Hawke make small adapters to go from dove tail to weaver/picatinny. UTGs are about 10 bucks, Hawkes are around 25. Hawke is better quality but both work fine.