There are a lot of new owners of modern sporting rifles based on the AR-15 design out there.  

Some people I know have purchased these rifles sight unseen.  Normally you wouldn’t recommend someone do this.

But when you’re talking about AR-15s, there isn’t much risk in buying something that the military and police use (in modified form). If you are unfamiliar with the rifle, the first time you handle one it is a bit of a departure from standard rifle designs. This is a good thing. The rifle breaks down easily, making all of the internal parts accessible for cleaning.

The down side is the uniqueness of the parts themselves, most notably the bolt carrier assembly and bolt itself. If you’re like me, you already had gun cleaning tools prior to purchasing your AR-style rifle. Most of these are useless when attempting to clean your AR bolt carrier and bolt.

Fortunately, a couple of companies have stepped up to make cleaning your bolt carrier easier.

The first of these products is the Otis B.O.N.E. tool.

MSR-AR Cleaning SystemBONE Tool

Otis introduced this tool in 2012 as part of it’s “MSR-AR Cleaning System”. It was re-introduced in 2013 as the “Improved B.O.N.E. Tool”, and re-packaged for individual sale. Otis has an informative video up as well showing you how to use the tool.

The B.O.N.E. Tool can be purchased individually for between $20-25. This is a great value for a specialty tool that will help you get into those deep recesses in your AR rifle’s bolt.  The tool looks like it is made from plastic from the photos. But it is one solid block of tool steel. The finish appears to be some kind of parkerizing and gives it a plastic look.

There are special cutouts on the tool for scraping the carbon from the bolt itself, cleaning the bolt carrier, and the firing pin. In addition, Otis adds a threaded insert for attaching one of their memory flex cleaning cables, turning the tool into a cleaning rod handle.

The B.O.N.E. tool is manufactured to fairly tight tolerances, and Otis warns the buyer that it may fit better in some bolts than in others due to manufacturing differences.

I have only two minor gripes with the B.O.N.E. tool.

The first is that because the surfaces of the tool are so smooth, they sometimes have trouble engaging the carbon they are supposed to scrape. Depending on how dirty you allow your bolt to get, this point may be moot.

The other gripe is with the size of the tool itself. Since it is manufactured to fit exactly into the bolt carrier, there is no room available to put a patch on the end of the tool to clean out the carbon you just scraped off.

That brings me to the other tool I’m using.  The C.A.T. M-4:

The C.A.T. M-4 can be found at most of the same places as the B.O.N.E. tool. It costs slightly more.  The C.A.T. M-4 performs almost the exact same functions. But it has a couple of advantages in my mind over the B.O.N.E.

First, it’s a flat piece of steel. This makes the C.A.T. much smaller than the B.O.N.E. You could fit it in your AR’s stock or grip with no trouble. Also, since it’s flat, it’s not going to roll off of your bench.

Second, the C.A.T. tool will allow you to use cleaning patches when using the tool.  Once you scrape all of that crud off of your bolt carrier, you need to mop it up. With the B.O.N.E tool, there is no way to use a patch to clean out the gunk. With the C.A.T., it’s a piece of cake.

Both tools are useful. If you own either one, your bolt carrier is probably cleaner than 95% of those that don’t. If I could only own one, it would probably be the C.A.T. But I’m glad I own both.