M*CARBO Brotherhood

New Sub2k - rusty bolt head

New here. Just got a brand new 40 cal Sub2k a couple weeks ago. Haven’t shot it yet due to all ranges being closed right now. Decided to clean it and noticed that the bolt had quite a bit of surface rust on it even though it seems like all parts had oil on them. Cleaned it a couple of times with Ballistol but still can’t get all of the rust out of tight spots and I’m sure the bolt has rust inside of it.

Trying to figure out if this is normal for a new Sub2K? Never had rust on a new firearm before. It’s not bad now after a couple of cleanings, but still…


Welcome to the Brotherhood, Alex.

First off, I’d take pictures in case you have to “discuss” things with where you bought it. It’s always nice to have photo evidence. :slight_smile:

Rust isn’t normal, especially on a new well-oiled gun. When you say the bolt, do you mean the bolt head (the part with the firing pin and extractor) or the bolt (the heavy weight hooked behing the bolt head)? Is that the only place there’s rust?

Fine steel wool will take surface rust off without damaging anything. If the bolt head has rust on it, I’d disassemble it and make sure the firing pin and the channel it rides in are clean. Be careful, the firing pin spring is stout. You can give the firing pin a very light coat of oil to help prevent rust, but DON’T put oil in the channel - that can cause light strikes due to hydraulics. Clean off any other rust you see and lube it up again. I’d look at the receiver itself too (the tube everything rides in).


Thanks. I meant the bolt head. The bolt (the weight) is rust free.
Yeah I should’ve taken a few pics, but I was too excited when I just got it and wanted to get it ready for some range time :slight_smile:
It’s not that big of a deal to me as long as it operates correctly which I’m hoping to find out in the next couple weeks. I might run the bolt head through the ultrasonic cleaner to get stuff loosened up inside there. Is it possible to disassemble the bolt head, seems like the pins are set in there?
My front sight is also not exactly level so still have to address that.


@lifeupnorth welcome to the forum alex


Absolutely. Both pins - the rearward one holds the firing pin and spring, and the forward one holds the extractor and spring - can be driven out with a punch. The firing pin spring is strong so don’t let it fly the friendly skies.:smiley: