By Ryan Cleckner
If you don’t take the right precautions, you can experience galling when you are connecting two pieces of stainless steel, aluminum, or titanium (and some other metals). Galling is the wearing away of the surface of certain materials that can lead to parts being permanently stuck together (friction/cold-welded).
For example, attaching a titanium muzzle brake to a stainless steel barrel or that same barrel into a stainless steel receiver can result in a permanent fusion of the two pieces. The term galling is also used for something that’s annoying. As you can imagine, both definitions surely apply here.
When it comes to working with certain metals — stainless steel, aluminum, and titanium are the most common with firearms — you need to add a protective layer between the two surfaces you’re joining to prevent this kind of friction/cold-welding. If you read instructions that come with some of these parts (I rarely do), you might notice that manufacturers recommend using an “anti-seize” lubricant during installation. This isn’t just to make the parts easier to install, it’s a necessary step to prevent the permanently fusing the parts.
These metals have a naturally occurring layer of oxide which protects themfrom corrosion. This is one of the reasons why these materials are so widely used in firearms. However, under the friction of being rubbed against each other (like threads screwing into each other), the thin layer of protective oxide can be worn-away exposing the raw metal itself. When these unprotected/raw surfaces come into contact with each other, adhesion (sticking together) can result. This is bad! The adhesion can be so strong that you’ll break the parts when trying to disassemble them or you won’t get them apart at all.
To avoid this problem, you can either use different materials or you can add your own protective layer that doesn’t wear away like the naturally occurring oxide layer does. For example, I’m a fan of stainless steel barrels. I like the corrosion resistance and the longevity that the harder material allows. However, when it comes to receivers, I’m partial to normal carbon steel.
There are two reasons for this. First, I like how the softer carbon steel “wears-in” and gets smoother faster and easier than a similar stainless steel action. Second, by using different materials I don’t need to worry about the metals galling (and I also avoid the feeling of how galling it can be to have stuck parts).
If you want to use these metals in contact with each other, then you must use anti-seize lubricant. A normal lubricant is better than nothing but anti-seize lubricant has properties that allow it to last longer and protect better. You can find anti-seize grease at your local auto parts store – a small amount will last you a lifetime of home-gunsmithing. Liberally apply the anti-seize lubricant to the threads, attach the parts to the proper torque specification, and then wipe away any excess lubricant. It’s that simple.
Knowing about and preventing galling will save you costly trips to a gunsmith and it will allow you to maintain and upgrade your products later. To many, a barrel will last a lifetime. However, I believe that a barrel on a rifle is like a set of tires on a car – eventually they’ll need to be replaced. Use the correct metals or use anti-seize lubricant to prevent a galling experience!
Ryan Cleckner is the author of the Long Range Shooting Handbook.