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2/22/2004 1:36:55 PM EDT
Hi,

I have a new Bushmaster rifle and I can see rust starting to form under the FSB. I always oil it really good, but still rust. Is there anything I can do about it? Will keeping it lubed stop it? Do any of you have this problem?

Thanks for any help.
2/22/2004 2:52:02 PM EDT
[#1]
Are you absolutely sure its rust? I had a similar thing happen on one of my ARs. It turned out to be a combination of CLP, carbon and some other baked on crap. Mine looked alot like corrosion, but it turned out it wasnt..
2/22/2004 3:03:33 PM EDT
[#2]
Every new bushmaster I have had will boil grease/oil out from under the front sight post... especially if you get the barrel good and hot doing some rapid fire.... it quits doing it after a while.  Are you sure it's rust?
2/22/2004 3:20:54 PM EDT
[#3]
I've seen the same stuff in the same location before on NIB AR-15 rifles, but it wasn't rust. It looks like rust, but it easily brushes off if you take something and scrub up in the cracks.
2/23/2004 6:08:19 AM EDT
[#4]
Thanks guys,

I'm not sure it's rust. The only way that I can really see it is to look at it with a flash lite. I'll try scrubing at it with somthing.

Thanks for the info so far.
2/23/2004 6:21:59 AM EDT
[#5]
Quoted:
Thanks guys,

I'm not sure it's rust. The only way that I can really see it is to look at it with a flash lite. I'll try scrubing at it with somthing.

Thanks for the info so far.
View Quote


I'm interested to see how it turns out Cliff, please keep us informed!
2/23/2004 6:48:53 AM EDT
[#6]
I have read here in the past that Bushmaster puts the front sight base on the barrel before they give it the manganese phosphate treatment. I assume this leaves bare metal under the base. So you may actually be seeing rust forming under there.

Bushmaster should correct this manufacturing oversight, in my opinion anyway.

Shabo
2/23/2004 10:17:39 AM EDT
[#7]
Quoted:
I have read here in the past that Bushmaster puts the front sight base on the barrel before they give it the manganese phosphate treatment. I assume this leaves bare metal under the base. So you may actually be seeing rust forming under there.
View Quote


I must confess to thinking the same thing before opening this thread.
2/23/2004 12:45:45 PM EDT
[#8]
Whatever this stuff is it comes off fairley easy with a tooth pic. I got most of what I could see but the rest is to far in the cracks between the FSB and barrel.  

If I find out that it's rust I'll let you guys know.  
2/23/2004 3:16:34 PM EDT
[#9]
Quoted:
I have read here in the past that Bushmaster puts the front sight base on the barrel before they give it the manganese phosphate treatment
View Quote


True. FALARAK is also correct that muck can ooze from mysterious places if you get the barrel hot enough.

I have 5 Bushmaster barrels that show no rust in that area. Even after several all day shooting sessions in the rain, all that's needed for maintenance is a little shot of CLP.

What kind of oil are you using? [url]http://www.thegunzone.com/rust.html[/url] There were some problems with the lube in some Otis cleaning kits a while back IIRC.
2/23/2004 3:53:20 PM EDT
[#10]
It isn't rust you're seeing; it is the parkerizing solution that's under the front sight base.  It can seep out of a new barrel, and sometimes it will dry and leave a bit of red-brown "crust" around the front sight base.  It isn't a problem and will clean up with a tooth brush and CLP if you want to get rid of it.

-Troy
2/23/2004 4:03:01 PM EDT
[#11]
All I use is BreakFree CLP and I have never shot a day in the rain. It looks like from what Troy said that it is not rust.

Thanks for all the help!  
2/23/2004 4:42:48 PM EDT
[#12]
Well i just cleaned and oiled another BM barrel Saturday. And as with the 6 or so other barrels i have had, the same stuff around the sight base. I do know that every New BM barrel ive had has had rust in the gas port on the front sight base. Its always been light surface rust, No big deal. Comes right off with a Q-tip and CLP. After Parkerizing you sometimes can get rust albeit just very light suface stuff. I still think the stuff where barrel meets FSB is still some sort of rust but i never had any problem with it, never gets worse and can useally get rid of it

G-Man
2/23/2004 10:20:24 PM EDT
[#13]


Ah!  Thanks for starting this thread.  I saw the same thing on mine but just CLP/toothbrushed it off.  Figured it was rust but couldn't figure how it happened to get there.


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