If you didn’t resolve this problem, I may have your solution. My 2746-20 18g Milwaukee nailer jammed and after clearing the jam, the “hammer/driver” would not retract. I found an online manual at Milwaukee’s website. It described how to “dry fire” the nailer.
1. Remove battery. (Already did that.)
2. Remove all nails. (Already did that.)
3. Re-install battery.
4. Turn on.
5. Open magazine, but don’t install any nails.
6. Press nailer against scrap wood and dry fire.
On completing the instructions my nailer would not fire. Then I realized the “nose” was not retracting in step 6. I had to push down hard to make that happen. Then the nailer dry-fired and the hammer/driver reset.
So make sure the doo-dad that is on the end of the nailer is fully depressed when you try to dry-fire. It was much harder to make it do that than when the nailer was functioning properly.
good luck!