streaks inside barrel [Archive] - Glock Talk


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01-14-2013, 04:55
Just noticed some grey streaks inside the barrel of my new Glock 19 Gen 4. They are at the muzzle end and look like they go a few cm into the barrel. Can't see if they extend all the way to the chamber end. They also come out of the barrel past the crown onto the angled bit. See attached photo.

I've only fired 90 rounds of FMJ and I've tried cleaning it with brush and solvent but the grey streaks are still there.

Is this normal? Should I be worried?


01-14-2013, 05:07
Normal just scrub it out! Use chore boy wrapped around your cleaning brush

01-14-2013, 06:02
Some of it is stubborn carbon fouling, but it's mostly just discoloration of the finish.

Get a phosphor bronze bore brush and cleaning rod, and turn the rod clockwise as you slowly move the brush through the bore, of course while the bore and brush are soaked in good bore solvent. After a few good passes, use the nylon brush and rod that came with your pistol and scrub the bore, then pass solvent-soaked patches through the bore and repeat. You'll see a lot of black stuff on the patches, that's mostly phosphor bronze residue that rubbed off of the brush bristles onto the surface of the bore.

I personally use a Dewey "No Harm" phosphor bronze bore brush with a Dewey brass bore rod. The brush and rod have absolutely no steel in them, the brush has a brass fitting and center wire with phosphor bronze bristles.

Don't try to fit a phosphor bronze brush into the cleaning rod that came with the pistol, they use different threading and you'll end up ruining the cleaning rod.

01-14-2013, 09:12
completely normal there my friend, nothing to worry about.

Bill Lumberg
01-14-2013, 11:30
Its fouling. I thought it was normal and unavoidable. Over time the streaks will keep extending as your round count builds It's not normally harmful but it's easy to remove. JB polish followed by JB paste will remove that quicly, leaving a mirror clean bore, all the way to the chamber, in about 3 minutes. Or you can use a lot of elbow grease.

01-14-2013, 14:43
Maybe need to clean it better? I've got 300+ rounds through mine and it's still got the mirror finish. Can't imagine it fouling up much after only 90 rounds.

SJ 40
01-14-2013, 14:53
I would suggest reading this posters methods,they will get your Glock or any gun clean.
While I use JB I have found Flitz or Semi Chrome milder and clean as well or better then than JB bore cleaner. SJ 40

01-14-2013, 14:59
I just hose it down with Ballistol, wait 5 minutes, and pass a Hoppes bore snake through my Glocks. Comes out squeaky clean every time.

01-14-2013, 16:34
Thanks for the tips!

Might get some of that JB stuff and try cleaning it again. Will using a brass brush instead of the nylon one damage the barrel?

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01-14-2013, 16:59
I just hose it down with Ballistol, wait 5 minutes, and pass a Hoppes bore snake through my Glocks. Comes out squeaky clean every time.

Bore snake really made my life easier. Pick you one up, use it correctly and all will be good and easy.

01-14-2013, 17:59
I have never used the cheap nylon brush that comes with the pistol. Buy a dozen brass bore brushes and you will be good to go for a while. No wonder you have fouling.

Bill Lumberg
01-15-2013, 07:35
Nylon is all you need unless you're using solvents that degrade the nylon. Bore snakes dust, but don't clean. That said, properly used brass won't necessarily hurt anything. I was raised on Hoppes #9, and still love it. But with modern chemicals and a regular nylon brush, it only takes a minute to clean the barrel.