I come across some interesting projects in my shop. In this case it is a Daewoo K2 rifle that needs its barrel removed so it can be cut and crowned.
The K2 family of rifles are 5.56mm semi-automatic rifles that are manufactured in South Korea by Daewoo (now known at S&T Motiv). While at first glance it is obvious the K2 shares many features with the AR-15/M16 M4 type rifle, it differs in its use of a long stroke piston to cycle the action.
If you aren’t familiar with Daewoo rifles, you are missing out. Back in the early 90s, one of my first semi-automatic rifles was a K1 (I shouldn’t have sold it), the carbine version of the K2 shown in this post. In many ways, that was a rifle years ahead of its time.
Since Daewoo rifles aren’t particularly common and very little information is written about them, I wrote this post to share how the barrels are removed if you ever find yourself needing to remove one like I did (and there was basically nothing to refer to).
Before we begin, let’s take a look at the disclaimer:
The contents of Rifleshooter.com are produced for informational purposes only and should be performed by competent gunsmiths only. Rifleshooter.com and its authors, do not assume any responsibility, directly or indirectly for the safety of the readers attempting to follow any instructions or perform any of the tasks shown, or the use or misuse of any information contained herein, on this website.
Unlike the AR-15/M16 barrel that is retained by a barrel nut, the K2 barrel is retained in the upper receiver by a partially threaded blind pin (above). The pin is threaded M5-0.8 for about half of its length.
Before I began to try to remove the pin, I used a M5-0.8 bottom tap to cut threads in the pin for the entire length of the pin. This will prevent the screw that I use for removing the pin from binding and stripping out the existing threads.
Once the threads were cut, I machined the small aluminum spacer shown in the image above. This spacer has a recess to receive the pin as it backs out. I simply place a M5 screw inside the spacer and begin to turn it clockwise. This begins to move the pin out.
The pin doesn’t come out all of the way. In the image above you can see approximately how far it needs to go to remove the barrel. With the pin out, the barrel can be removed; however, it is still press fit to the upper receiver.
While there are a number of ways to pull things apart, many will damage the parts. I found using a AR-15/M16 barrel extension wrench was the best answer. I inserted it into the rear of the upper receiver and began to tap the barrel out.
With the barrel out, you can get a good look at the barrel extension on the K2 rifle. note the relatively shallow hole that the blind pin sits in.
Another look at the disassembled upper receiver. To put it back together, barrel installation is fairly straightforward. Simply push the barrel back into the upper receiver and drive the blind pin back into place.
In case you were wondering, this is what the upper looked like after I cut the barrel down to 16.5″ in length and threaded it 1/2″-28.
The Daewoo K2 is a neat little rifle. If you get a chance to work on one, don’t pass it up! If you need work done to your K1 or K2 rifle, check out 782guns.com!