ok here is your dilemma you are playing with a gun that was widly used and no one makes parts for...the good news is the remaining parts for your gun are dirt cheap because the store who have them think they are stuck with them. so i am going to go out on a limb and say you are probably still using the stock metal bolt. i have a point i promise! what you need to do to remedy your problem is what i did. because you are not going to find detents any better than the ones you are using because they were never made well in the first place. so here is what i did i went out and bought a Bob Long venturi bolt it is made of delrin and has smaller groves but it isn't sharp at the end so it won't cut your detents like the stock bolt. this fixed my problem and also reduced the number of breaks i had drastically!
here is the link to the bolt on ebay it is $5.99 with free shipping.
as for detents i use these
funny thing is the detents cost more than the bolt.
if you have any other questions about your gun let me know. i spent far to long online, finding ways to make it shoot better, to only benefit myself.