Originally Posted by bayoutrigger
Get a heavier recoil spring from Wolf.
Agreed. I had the same problem (amongst many other problems) with a used MK40 elite98 and solved the problem with a Wolff recoil spring assembly. Funny enough, the problem went away with the standard 20# set up, which with the Wolff felt much more assertive. Still, being the tinkerer I am, I stubbornly still went up to 22# and found that stout rounds were needed to make it 100% with this set-up.
On my PM9, both the original and recall replacement set-ups did not have any problems with returning to battery.