CLEANING TIP — Be Careful with Brushes and Jags
We recently had a discussion with the barrel-makers at Bartlein Barrels. They confirmed that they have seen many, many more barrels harmed by crown damage caused by improper cleaning than by anything else. If you use a bronze brush, Bartlein recommends that you remove the brush after it passes through the muzzle. This is because the bristles take a set (pointing to the breech) during the out-stroke. In other words the bristles angle back as you push towards the muzzle from the breech. If you drag the brush backwards at the muzzle, you force these bristles to reverse direction abruptly right as they cross the delicate crown. In time, that can damage the crown. John Krieger of Krieger Barrels also advises his customers not to pull a bronze brush backwards across the crown.
Response to Skeptics
Whenever we’ve published similar advice, given by guys who are producing some of the most accurate barrels in the world, some readers get extremely angry. They say, “You’re crazy! I’ve was pullin’ triggers when you were still in diapers. I’ve got Hall of Fame points and I say there’s no way a phosphor bronze brush can ever do anything to steel. You’re full of it.” Well, these guys are entitled to their opinion. But here’s our response. Number one, we’re just telling you what the barrel-makers are telling US. Don’t kill the messenger. Number two, many of the guys who say bronze brushes can’t affect the crown are the same guys who feel they need to recrown their barrels every 400-500 rounds (Do we see a connection?). Third, if you don’t think a softer material can affect steel, look at the steel ferrules of a well-used fishing rod — there the steel is worn away by plastic. (With time, water will wear away granite.) Lastly, this Editor can tell you I’ve seen the damage myself, first-hand, using a magnifying glass on much-brushed benchrest barrels. Right at the muzzle, the top edge of the lands had sharp, jagged edges that looked like little shark’s teeth, or the edge of a serrated knife. By contrast, a new barrel will have a nice, smooth straight edge along the top of the lands at the muzzle.
Be Careful with Jags
Bartlein’s experts also told us to be careful about the jags you use. Dewey-style jags in particular can cause problems. These have a long shaft with multiple rings with diamond-pattern “teeth”. The teeth are designed to grip a patch. The problem is that the lower rings may be exposed below the patch fabric, so the teeth can grind directly on the rifling and/or crown. Bartlein says Dewey-style metal jags can damage a crown very quickly if any of the toothed rings are exposed, metal-on-metal. Tim North of Broughton barrels also advises against using the Dewey-style jags with toothed rings. Interestingly, Dewey uses the same type of diamond-shaped teeth on the bottom of its “Crocogator” primer pocket tool, so you know those knurled teeth can scrape.
My engineering sense (and my common sense) is telling me that hot gas and particle erosion (as the bullet exits) will be much, much harder on the crown than any brush could ever be. The observed “serrations” on the crown might very well be the natural result of shooting.
Still, this might be very good advice. All that remains is for someone to quantitatively demonstrate the effects of this brush-induced crown wear on accuracy.
(I’m not volunteering.)
I’ll stay out of the crown discussion (insufficient experience) but the editor makes a couple of misleading statements:
“…look at the steel ferrules of a well-used fishing rod — there the steel is worn away by plastic” is incorrect. Fishing line, like many nylon filaments, often contains titanium dioxide, which is an excellent abrasive. Nylon itself has an extremely low wear rate vs. steel – that’s why it’s used for bearings.
“With time, water will wear away granite” isn’t too accurate either, it’s the suspended particulates (sand) that does the erosion.
The reason that soft materials often wear away much harder ones is the principle of lapping. Abrasives, grit, etc. embeds in the softer material and abrades the harder. No grit = not much wear. Your nylon coated cleaning rod won’t damage your expensive barrel if the rod is clean, but if the rod is allowed to pick up crud it will abrade the steel.
Would this not be a good reason to use cheaper plastic jags vs the metal ones?
I’ve used Dewey rods and jags for years. Grind or sand off 2 of the Dewey toothed rings closest to the treads and/or use a slightly larger patch. Problem solved !!! Common sense can prevail.
I agree with shooter that grinds off the 2 areas closest to the threaded end. I place them when new in a drill with the tip-end in the drill so the surface of the jag is not damaged. It does not need to be too tight to allow you to spin the two areas on the jag over a the edge of a good file. This will remove the rough teeth and reduce the diameter of them as well. They can be smoothed even more with some fine sand-paper. I also use patches that cover all bumps on the jag as well. These are great jags if you prep them and use the best size patches.
Telling about all the “bad” jags, can anyone tell me what jags are good to use?
Paul,
There are a lot of good jags out there. I personally like the MidwayUSA nickel-plated spire-point jags. These won’t react with chemicals. They have a smooth, cylindrical “bearing surface”, and then the diameter of the jag is reduced in steps. I generally use one size under nominal bore diameter (e.g. a .22-cal jag in a .243 bore).
Here’s a link to a kit with multiple jags: http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=812503
Photo: http://www.midwayusa.com/midwayusa/staticpages/highres/812503.jpg