Over the weekend, I barreled up a spare new Colt M4 1x9 on a Colt M4 flattop.

I've had the barrel for well over a year in storage with a bunch of other barrels.  Nothing wrong with it when it was put away.  I did a quick inspection of my box of barrels and none of the other ones were affected.

Didn't bother to look it over prior to assembly, as I never would have thought anything was wrong.  When I was ready to check the final assembly with a GI field guage, I noticed rust around the area where the barrel and barrel extension meet on the chamber end.

Sprayed it with WD-40, bore cleaner, used a GI chamber brush, and scraped it with a dental tool.  Cleaned up most of it, but the rust is still evident.

Personally, I do not think it will affect performance, as long as I keep it lubed while in storage.  It's just one of those things that bother me.  Any suggestion on how to clean up the rest?  Anyone know of an improvised tool that will help?  

 

I am having a hard time figureing out what you are talking about

Is it the rear of the barrel inside the barrel extension?

I had a rusty OLYarms I bought from someone here (not to name names : )  ) Terrible bore-  I had just gotten a sample of FP-10 the new CLP replacement and I just soaked the bore for a day and then brushed it for about 3 hours and finally the bore seemed to have been restored and was shiny [b]I ruined 2 cleaning rods and 3 bore brushes doing this[/b]

Then I soaked the bore with CLP for a week and brushed it for like 20 minutes with Flitz metal polish and soaked for a week and brushed with flitz bore polish and it looked almost new.


Getting rid of rust is hard but FP-10 and FLITZ will help you get there.

The rust is not in the bore, chamber, or outside.

It is behind the locking lug recess area, around where the barrel mates with the barrel extension.  You can only see it if you were looking from the chamber end.

I probably have to take the barrel off and soke the end for a few days.  Then scrub with a brass brush.  Dang, this was one of those perfect one shot barrel jobs too.

Any other suggestions will be appreciated.

Wherever it is a chamber brush some elbow grease and some FP-10 should get rid of it.

You may need to buy a new chamber brush let it soak for a week and then attack it.  that way the rust will be loosened and the chamber brush will not be to used to reach the spot.

It doesn't sound very bad I wouldn't be too worried if I were you (I'm sure that barrel is perfectly serviceable).  

The one I was talking about was so bad that the first brush I pulled through it resulted in about 1/2 a cubic Centimeter of iron oxide (rust particles) comming out of the bore THAT SCARED ME. I wasn't about to send it back though- a person that sells that kind of a barrel is not probably going to refund the money anyway.

It sounds to me that when the barrel was finished (parkerized or blued?), they did not leave it in the boil out tank long enough to stop the process. If you are seeing rust around the joint, you can be assured the threads and stuff you can't see between the barrel and extension are rusting too.

If you don't stop it, it will ruin your barrel.

Here's the best way to stop it.

Remove the barrel from the receiver.

Submerse the breech end of the barrel, at least 3" past the extension, in boiling water for 15 minutes. This will nutralize the parkerizing or the blueing salts in the threads.

Immediately submerse the breech in WD 40 until cool. I know we don't like using WD 40 on firearms, but the WD stands for Water Displacing, and its the best for the job.

Clean and reassemble. You should not have any more problems.

Good Luck,
Lee
[url]www.thearmsroom.com[/url]

I did what Hadaway recommended.  Looking better now.

Boiled for twenty minutes, then dumped chamber end into a cup filled with enough WD-40 to get past the chamber.

I had to bribe my two kids to not rat me out to mom for using one of the pots for this endeavor. [}:D]

Ah, the kids....wife was off for a weekend a while back and I had to bribe mine.....daddy, what are you cooking? I was happily baking my mags after a good cleaning in prep for spraying. Gotta laugh!