Hi all,
So I was changing the spring on my ics m4 to a m90 as it was shooting to hot with the new tight bore. I took the upper gear box apart. changed the spring and put it back together again (with great difficulty).
however when I went to test it to see if still fires okay, nothing happens no noise or anything.
Does anyone have any idea what's happened and how I can fix it?
Thanks in advance if you can help a noob out.