AR-15 Maintenance: Roll Pins

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AR-15s are pretty much pinned together. While a staple for many AR-15s, roll pins are not hard to work with, but a misstep could be catastrophic enough to permanently damage your AR-15. Here’s how to perform the essential construction operations associated with roll pins—the professional way.

Start the (oiled) roll pin using a starter punch. Drive it as far as you can with this tool. Switch to a nibbed-end punch and drive it on home. Protrusion should be equal on both sides, which means it ends up just a little below the surface. Finish with a dab of touch up paint. (Normally I’d have covered the area with masking tape to help ensure against accidental marring, but I left it off for better photo clarity.

AR-15 parts assemblies—ranging from the gas tube to magazine catch, bolt stop, bolt components, forward assist, sight parts, and more—are secured using roll pins. I’m not trying to talk anyone into banging on their guns, but there certainly may be times when a part replacement is in order, and something really simple, like replacing a bolt catch with something from the aftermarket, requires little more than a small collection of tools and a little insight into the process. Alternately, you might be ready to tackle a full-on build project, and that requiring a little larger tool collection.

two roll pin punches

Pin Punches. You really need a set of these. They are roll pin punches, one to start and one to finish. The starter punch has as its sole function and favor getting the oversized pin started into the hole. It’s sized to fit the outside of a pin; pin goes inside the punch. After the pin starts and is fully on its way, then switch punches to the one with the little nib on its end and send it on home. The nib fits into the hollow in a roll-pin and helps “grip” the pin so it can be seated to flush, plus, without unnecessary marring. Seating roll pins is a difficult and scratch-and-ding producing job without such a punch pair. Tip: drive the pin as far as you can using the starter punch, without contacting the part itself with the punch end.

A roll pin is a hollow pin with a split down its body. It’s oversized to the hole it fits into by about the gap width of the split. It squeezes down as it enters the hole and this tension keeps it in place. They are beveled on their ends but that’s not nearly enough to get one started gracefully, and that is the trick— gracefully or not—getting one started. Of course, there are specialty tools, and those are roll pin punches. Get some. For a basic build, you’ll need #s 1, 2, 3, and 4.

The ends of roll pins are often craggy or out-of-round, or both. These are not precision-made parts. Smooth and polish the ends of every roll pin you install. This doesn’t take much effort or time and is a worthwhile step. The easiest way is to lightly chuck one into a drill and spin it against some emery cloth or a stone. I do both ends because removal is easier when both ends are polished.

Steel pins going into aluminum holes make life way harder on the holes than the pins. I can also tell you that a drop of oil helps and will never diminish the hold of a roll pin. That also reduces any corrosive “sticktion” potentials between the aluminum and steel, making the pin come out easier too.

It doesn’t take undue effort to drive a roll pin, but true hits count. They can bend. Most roll pins are a little shorter than the full span of the hole. So, with the pin ends at equal depths, should leave each end a tad below flush with the part surface. A roll pin should never protrude above the surface to ensure no snagging potential.

Using a slave punch to line up the holes

Lining up. Get in the habit of using a capture or “slave” punch, which is simply another, correctly-sized punch, to line up associated holes prior to roll pin installation. Use the roll pin progress to drive the capture punch out. Really helps.

Ready for Work

You’ll notice that there are punches of varying lengths used in the work shown. The shorter ones are a little easier to operate but the longer ones are necessary for some installations, simply because they give clearance beyond rifle parts you don’t want to accidentally mis-hit with a hammer, or have the larger diameter handle portion in contact with a rifle receiver.

I often chuck up a small punch and polish the outside using emery cloth. They’re not all perfect, and at times, these little imperfections are annoying if not damaging. This is especially true when using one as a capture punch, such that it has to extend fully through the hole set. Likewise, with use, they often get a tad deformed around their edges, and that’s easy enough to true up with a stone.

Choose and use the right punch. A punch that’s too small for the pin will tend to deform and also expand the pin end. One that’s too large may also deform it, and won’t ultimately enter the pin’s hole to seat the pin-end correctly. Use a brass-headed tap-hammer for punching punches. It’s plenty enough power, and a slip won’t cause undue marring.

roll pin with the end deburred

Pre-Pinning. Get some emery or a hard Arkansas stone to run roll pin ends over before assembly. The ends are usually rough and irregular. It’s easy and makes for easier work. Assembly is greatly assisted but it’s also disassembly that improves when the ends are deburred. Just chuck the pin, lightly, in a drill and run on an angle for a few seconds.

I can’t tell you much about running a punch that you won’t learn on your own, but make sure the end is centered and stable and the punch is in-line with the pin. A “follow-through” sort of strike is usually better than mimicking a woodpecker. Whack! works better than tippy-tap-tippy-tap.

Oh, and tape! Use masking tape all over the working area. It is not a sign of weakness. Tape the fool out of everything around the installation and it’s less likely to need touch up afterward. However, touch-up finishes any pinning job and gives it a “factory fresh” appearance. I use a flat-black paint marker from Birchwood Casey. It works wonders.

Last Words

Aluminum alloy cracks, or dang sho can if it’s subjected to sharp impacts. Don’t allow gaps between the impact area and the workbench. Back up the receiver, especially on the trigger guard, and also rear sight windage knob (the screw is easily bent). A piece of wood is all that’s needed.

Can you reuse a roll pin? Sure. As long as it’s not been unduly damaged from removal. That means the ends are still tapered and the pin is still straight. This may not happen with some of the larger pins on the gun, but something like an ejector pin can be reused without worries.

Do you have a tip for maintaining your AR-15? Share it in the comment section.

The preceding is a specially-adapted excerpt from the book The Competitive AR-15: Builders Guide by Glen Zediker and Zediker Publishing. For more information visit and to purchase go to

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The mission of Cheaper Than Dirt!’s blog, “The Shooter’s Log,” is to provide information-not opinions-to our customers and the shooting community. We want you, our readers, to be able to make informed decisions. The information provided here does not represent the views of Cheaper Than Dirt!

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