Printed Barrel Instructions: 

Step 1: Print barrel (Best orientation is vertical). Ensure you have your settings dialed in so your dimensional accuracy is good. If you have over extrusion you’ll have a very hard time seating your liner in the barrel and it’ll require additional post-processing. 

Step 2: Test barrel liner fitment. You should be able to easily insert and remove liner. 

Step 3: If you printed a multi piece barrel - designed for smaller printers - super glue or epoxy your pieces together. 

Step 4: Cut liner to length. You can cut with a hack saw or Dremel. You want to leave a little extra that you will file and sand flat and square with your barrel. Use your barrel as a guide but be careful not to damage the ends of the printed barrel. 
	
Step 5: Once your liner is the correct length, you’ll want to remove the liner and cut your chamber. You can use a chamber reamer for 22LR, OR a #1 or 5.7mm drill bit. I’ve found that if you’re using a drill bit, it’s best to put your liner in a drill press in the chuck. Then put the drill bit in a drill press vise below the liner. Spinning the liner will self-center the drill bit and get you a centered hole. However, a hand drill can be used if you're careful. Drill the chamber to a depth of .775”.

Step 6: Once you’ve drilled the chamber, de-burr and lightly chamfer the breech end. Test with a blank or empty case for fitment. If your cases are too tight, you can polish the chamber with some fine sand paper to get it smooth. 

Step 7: Do not complete this step until you’ve printed your upper receiver and are ready to test your final head spacing!!!
Sand the outside of your liner with an aggressive grit of sandpaper. Clean with alcohol or acetone to remove any oils or dirt from the exterior of the liner. Mix and Add epoxy. I recommend the classic JB Weld metal filled epoxy. It takes a day to cure but is very strong. Coat the exterior of your barrel lightly with epoxy and press into barrel. Press it past the end of the barrel so it sticks out the other end, then press it flush with both ends. Moving it back and forth once will make sure the epoxy can move into the layer lines of your print. Clean up excess epoxy with a damp paper towel around both ends of the barrel. 

Step 8: Head-space your barrel. Mount your printed barrel in the receiver and tighten down the v-block screws to ensure that the printed barrel is secure and at its farthest point into the receiver. If you've printed the takedown version, insert the barrel into the shroud and secure it using the M5 bolt in the bottom of the shroud. Insert a blank or empty casing in the barrel and install the bolt in the receiver. Using the bolt as a head-spacing tool, press the liner into the bolt until the bolt face is against the casing and there is no gap. It should be very close to the face of the printed barrel. Allow your printed barrel to cure for 24 hours before moving to the next step. 

Step 9: Gently file a groove on the edge of your barrel liner where the extractor groove is until it matches the profile of the existing groove. Less is more here, only file until the extractor can reliably pull out a round. No need to do more than that. If you file too far you’ll get swelled cases and OOB adventures. 

Step 10: The threads on the end of the barrel are 1/2x28. If you have a metal muzzle device, you can chase the plastic threads with that. If you’re using a printed thread protector, be careful and go slowly as you thread it onto the plastic barrel. Use lubricant if necessary. These plastic threads are not very durable. It is not recommended to use them for suppressors. They will likely fail. The Sneeki Breeki threads are more durable but only allow printed components or brooms to be attached.