I had a redline n7 drop in in this gun. Performed great and the alignment is perfect. It is a bit too long for my taste so I removed the hpa engine out of it. Selling the complete body without the hpa engine. All you need to do is put in your hpa unit and you are good to go. If you want to convert it back to an AEG you just need to put in the parts. The gearbox is still there. No inner barrel/attachment included. $185 shipped