Di bolt carrier discoloration

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Re: Di bolt carrier discoloration

Postby Mossyrocks » Wed Mar 15, 2017 10:08 am

It doesn't bother me, the picture I posted is out of my adjustable suppressed piston rifle with 3000ish rounds through it. It is clean in that pic and very dark.
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Re: Di bolt carrier discoloration

Postby rcrandall » Wed Mar 15, 2017 5:01 pm

There seems to be a slight flavor of piston vs DI in this thread. There is a difference and most people are here because they like the piston operating system but everyone needs to keep in mind the DI system works fine, specifically those that are made with quality parts by quality people. I've been running DI guns since 1987 and have been an armorer for them for years as well as a rifle instructor. They work if you half ass take care of them. I prefer LWRC's piston, it's reliable and clean and fun to shoot. But I would use a properly made DI gun in a second if I couldn't use a piston. So in other words, let's not argue about what's better, they both work.
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Re: Di bolt carrier discoloration

Postby NMGuy » Sat Mar 18, 2017 4:15 pm

My piston rifles run very clean. I can take them out and put 500 rounds downrange and they're cleaner than 60 rounds through my DI rifle. Once I put my can on the piston rifle it does get very dirty though. Still not as dirty as a DI but it's pretty close, the hard to reach areas stay clean still but the external surface of the BCG and upper get covered in crud. Even my trigger group and buffer tube get some crud. Mags also get very dirty as well when using the can. Running suppressed on a DI is much dirtier than normal as well.

That's the only downside to using a suppressor. Everything shoots dirtier. Rimfires especially.

All my rifles I shoot suppressed have discoloration on the BCG. I'm assuming this is because of the way NiB surface is. It's not flat, microscopically it's supposed to be like a bunch of tiny triangles and I'm assuming the gaps in between collect microscopic bits of the black carbon so that's what discoloration. A little bit of polish that's safe on Nickle will clean it right up if you so desire.
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Re: Di bolt carrier discoloration

Postby Merlin32 » Thu Mar 23, 2017 4:04 am

Sounds like you're making the argument to purchase an lwrc piston variant :)
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Re: Di bolt carrier discoloration

Postby NMGuy » Sun Jun 11, 2017 2:45 am

Part of the discoloration is the way the NiB surface is. It's not "flat" more of microscopic ridges which is why it feels slick. The gaps between the ridges can collect dirt, oil, etc. doesn't effect function.

If one wants to clean their BCG back to a shiny new finish (which will be ruined when you shoot it again), get some sort of polish.

Brasso works okay. It will get a lot of the discoloration out, but Mothers Mag and Aluminum polish is the best I've seen. It will polish it back to the very shiny finish you get from the factory. Just be sure to get whatever polish you use, especially the mothers, off of the Bolt carrier. Mothers is not good for anodized finishes or paint (any finishes used on AR type receivers). Just rinse well with hot water and wipe it all down a couple times with clean cloths and gun cleaner before reassembly.

I occasionally do this to my NiB BCG's. About once a year I clean my firearms all really well. They may not get cleaned again for another year though! I'll upload a picture of what it looks like after polishing a BCG that has had over 9,000+ through it, 3,000+ of them suppressed. It was almost completely black/dark grey in color.
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Re: Di bolt carrier discoloration

Postby van halen » Sun Jun 11, 2017 3:43 am

Mossyrocks wrote:
van halen wrote:Agreed, never done anything beyond a wipe off after many thousands of rounds. Carriers still look shiny and new.

You don't notice it in DI rifles with black BCG's.

Did no one else's piston BCG's turn a dark grey? They're still smooth and shiny, just darkened up a lot thousands of suppressed rounds later.

I've never run a can on mine......
I'll just sit here quietly and play with my new rail panels...........
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Re: Di bolt carrier discoloration

Postby jadams951 » Thu Sep 07, 2017 9:11 pm

None of my chrome Young Manufacturing M16 BCG get discolored like that! :smartA: :smartA: :smartA:

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