A few years back I made the mistake of clicking into this forum, and ofcourse browsed through the collection pic thread.  My bank account was doomed to suffer great losses.

I've learned a bit about the hk clone market since originally purchasing the Belator Arms BA89k. I seemed to have gotten lucky with mine, and it runs great with factory HK magazines, and has FTE's with the aftermarket mag it came with. Recently I was toying with some subsonic 9mm loads in 147gr and 124gr, I took my 9mm AR and my BA89k, both of which are SBR's, to the range to check velocity and function. Shooting the 9mm AR suppressed with subsonic is awesome, the report heard is like a loud stapler followed by the whack as the bullet hits the plywood target stand. Switching to the BA89k with the same loads obviously unable to fasten the suppressor left my ears ringing and my mind wondering why I didn't think I would want one with a threaded barrel.

The search for "how am I going to get a threaded barrel" started last year with an email to gun smiths who was said to be able to weld on an extension and thread it without removing the barrel. When I inquired I was told that he would not work on a non HK clone. Okay, I guess. So then I emailed some other smiths who didn't seem to care about being a clone to check costs of swapping barrels, most of which came close to 50% of the cost of the gun just for labor. I started to dig into what it would take to do it myself, and luckily there are a ton of great guys out there that have full clone builds from flats online to reference. "Well if they can do that I can surely swap a barrel myself".  I am a total DIY'er so I see guys bending flats into receivers, welding, pressing barrels, pins, etc and now not only could I swap my own barrel I could build my own clone!!

After talking with a friend about making some tooling and a barrel press rod on his mill/lathe, I sat down and ordered the barrel and pin, and also ordered aluminum to make a receiver clamp for pressing out the barrel pin. I wanted to do everything possible to make sure I don't screw up my SBR'd receiver.

So here is the current state of progress.

I bought a 20 ton press from HF.


Verified that it is indeed working.



Received the RCM barrel and pin.


Checked progress and fitment of the clamp my friend is machining.
Looking good!!!!

I've also specified I want two dowels turned for pressing the barrel pin out. One for the initial push on the pin that will only just be tapered down to fit the pin, and one to finish pressing the pin out.

Very nice!  
Please keep us posted on your progress.

Pressing the pin out was really easy with this jig.




Barrel pressing rod and brass end insured the barrel isn't damaged.

The barrel took a bit of force to move, once it moved a little I used needle files to clean up the edge where the pin was drilled on the barrel inside the trunnion.

Looking awesome!

Barrel pressed in. Bolt gap at .020.

Test fit parts. Still have to do some welding on the front sights.

Then drill and pin!!

Anyone running a suppressed mp5k?  Does the locking peice need to be switched to 120*?

According to HKParts.net, it's the 80*.

http://www.hkparts.net/shop/pc/MP5K-Bolt-Carrier-Bolt-Groups-c144.htm