Q: What are the specs of your liner?
A: I use Redman’s 22LR Liner.

SPECS: 4140 steel.

.223″ (5.6mm) groove diameter

1-16 twist (LR)

5/16″ (7.9mm) O.D.

Q: Why can’t I see any rifling when I look through the liner?

A: The liner ships coated with oil to prevent corrosion. Use a 22 cal bore snake, or a gun cleaning kit to swab the liner out with solvent, and take a peek at that beautiful rifling. The oil hides it well.

Q: Which end is the chamber/muzzle?
A: After cleaning the liner, carefully inspect both sides. One side will have a larger hole. This side is the chamber. You should be able to drop a dummy round/bullet into the chamber end, and the rim should sit on the end of the liner. The other end is the muzzle, and you should only be able to put just the tip of the bullet into that end.

Q: I ordered a threaded liner, why isn’t it threaded?
A: None of the liners I sell come with direct threads. When you select threaded, you are selecting the correct length for the printed threaded barrel.

Q: My printed barrel broke. Is there any way I can re-use the liner?

Yes, most of the time. If printed in PLA, you can bake the broken barrel at a low temp, and use a pair of pliers to pull the old liner out. You will need to thoroughly clean off the old jb weld, and any plastic still attached before re-using the liner. If barrel is printed in nylon, the same process can work, but nylons heat resistance may exceed your normal ovens temperature range. In this case a torch should soften up the nylon enough to cut it off the liner.

Q: How long do barrel liners last?
A: Liners are made from the same steel commercial 22 barrels are made from. You can expect many thousands of rounds of shooting out of a liner before it is likely to start showing chamber or rifling damage. More often than not, a liner is damaged during installation. If installed properly, it will outlast the printed plastic components.

Q: Why is there no extractor notch on the liner?

A: This is a step that must be preformed by the builder. Fortunately it’s very easy to do and only takes a few minutes. In many builds, you can notch the liner before you install it, and rotate that notch into place before the JB weld cures during installation. This is often hard to do due to the various design constraints. If you need to add the notch after installing into printed barrel, needle files will usually make quick work. When notched outside the barrel, a flat file on a bench works well. In either case, you want to make sure you avoid touching the inner diameter of the chamber on the liner. If this happens, the liner has been damaged, and must be cut shorter and be re-chambered ($10+Shipping).

Q: How do you attach the barrel liner to the printed barrel?
A: JB Weld is the most common way to glue the liner in. Many epoxies and plastic welders have been tried, and most fail rather quickly. The classic, slow curing formula of JB Weld seems to hold up the strongest. Steps to install:

0. Test fit. Makes sure the liner fits in the hole with no glue, make sure it’s the right length. If you need to, drill out the printed barrel with 5/16 long drill bit.

1. Clean thoroughly, wipe down with alcohol.

2. Lightly sand the exterior of the liner, scuff its outer surface to aid with adhesion

3: Wipe again with alcohol.

4. Apply JB weld to inside of printed barrel. If barrel is threaded, apply extra under where threads will be.

5. Using a dummy round to keep JB weld out of the chamber, press liner into barrel. Insert the chamber end of the liner into the muzzle end of the printed barrel, and with constant pressure, press the liner all the way through the printed barrel, until the liner is roughly in place.

6. Clean off excess JB Weld, remove dummy round, and clean inside of barrel liner to ensure no JB weld dries inside.

7. Use the bolt or breach face against the barrel with a clean dummy round inserted into the chamber to set the headspace. You want the bullet to sit snugly between the bolt/breach face, and liner with no wiggle room, while ensuring that the bolt/breach face can sit snug against the dummy round with no gap.

Q: Why doesn’t a .22 caliber bullet fit through the barrel without being fired?

A: A .22 caliber bullet is designed to fit snugly in the chamber of a firearm, not to slide freely through the barrel without being fired. The bullet’s diameter is slightly larger than the barrel’s bore to engage the rifling when fired, which imparts spin for accuracy and stability. Attempting to push a .22 bullet through the barrel without firing would be difficult due to this tight fit and could damage the bullet or barrel. This is normal and safe, as the liner is engineered to handle the bullet only when propelled by the force of the firing process.