am looking for helpful suggestions for a good alternative to our current ABS material that is failing, probably caused by fatigue / mechanical ageing.

Our current part is failing in the field after three to six months of use. The failure is a fatigue failure very near the pivot pin of a trigger. The surface shows typical clamshell pattern failure and it is slightly polished where the break starts and white/grey where it the break ends.

We used a Polycarbonate - Acrylonitrile Butadiene Styrene blend on a prior version of the part and by going to the Acrylonitrile Butadiene Styrene (Entec-Resins, type 756) almost doubled the life using our stress test jig.

Shrink rate may not be totally critical so I am open to going away from the ABS solution.

What are my options?
Glass filled ABS
Nylon
PP

Many thanks for your help!