98 custom platinum series act(fireing problem)

Try checking out the sear that holds the bolt in place, those can be worn down after long periods of play and they ware down alot faster with a r/t trigger installed. Also because you have a new bolt in there, there may be less surface area on the aftermarket for a shorter and lighter trigger pull but that combined with a worn down sear will cause it to do that. Just check and make sure the sear has a pretty good edge on it and not rounded or chipped in any areas. One other thing to check would be to make sure there is no debris imbetween the pin and the hole of the sear that fits around it, that can cause it to keep firing sometimes. Good luck, hoped this helped a bit.