[marksman1941]

After pushuing the pin in and out about 20 times one night (I kept forgetting to pull the trigger as I pushed the mainspring back in, and it kept pulling the pin out) it got much better. Now I really have no trouble getting it to slide back in.

 

[marksman1941]

When mine was still super tough to push back in, the best thing I found was to take a solid steel screwdriver and set it crossways on the back of the pin. then you can grab on either side of it, set your thumbs on the top of the receiver (near the hole for the pin) and squeeze em together. It works really well, and as long as you don't slide the screwdriver it won't even scratch the mainspring.