What MM is describing is called "mortaring" it open. Works great with an A1 or A2 style stock, but I've disabled cheap a cheap retractable doing that.
Another option is to place a block a wood against the charging handle and hammer it open.
What make is the gun?
If it's a parts gun, who's barrel and bolt carrier group are we working with?
It says Anderson Manufacturing , Made in Kentucky AM-15 Multi cal .
