Pitting on the bolt?

[BikerBCM]

I just shot my new BCM yesterday. I shot around 130 rounds, mostly Remington with a little Tula mixed in. Today when cleaning I noticed what looked to be pitting on the rear of the bolt.

Not on the bolt face but to the rear of the gas rings where it is narrow. I apologize as I do not know the exact term for that part. Also the raised ring between the bolt lugs and the gas rings appears to be pitted as well.

The BCG is a BCM auto and has only fired 130 rounds.

This doesn't seem normal as my issued early M16A1 is still smooth.

I did try search but the search fucntion kept giving me errors. I will try posting a pic if I can figure it out.

BikerBCM

[mikejg]

Use the orange search button. It should work. Without a picture, it's probably carbon build up from firing it.

[evolixsurf]

http://www.gngtools.com/

[BikerBCM]

See the pictures..They arent the greatest. I ran a sharp knife across the sruface and cant seem to scrape off any carbon. It also seems as thought I can feel the pits in the metal with the tip of my knife.

[evolixsurf]

hmm, on that second picture it looks like it is actually pitting. I would say this, contact BCM now about it, and shoot a bunch more rounds through it. It might smooth out. If it doesnt, I would send it back. Ill look at my BCM BCG tonight to compare.

[Magsz]

Did you have any function issues?

Is the bolt unlocking easily and not binding in the carrier when you pull on the charging handle?

I would personally shoot the crap out of it as i have a few bolts that look like that on the tail area and they all function just fine and havent corroded into heaps of metallic dust...yet. :)

[BikerBCM]

I had no function issues. Bear in mind I have only fired 130 rounds through her. Total.

It unlocks easily as when it was new.

BikerBCM

[markm]

Minor pitting behind the gas rings is not a problem. Any pitting near the lugs is what causes bolt failure.

[ArmySGTPM]

I have a brand new BCM BCG that has the very same look. I was wondering about this very thing today. Shot only 100 rounds through it to get my new rile sighted in...no function issues, but just looks like the metal is not smooth an is definitely not carbon build up, my first thoughts were pitting of some sort. But seeing yours reassure me a little...do all BCM bolts look like this?

[Heavy Metal]

Proabally an artifact of the Shot-Peening process.

[Col_Crocs]

Proabally an artifact of the Shot-Peening process.
This too crossed my mind. Quite common from my experience... A bit more prominent on BCMs than on DD's Ive seen and handled. I could tell right off the bat it wasnt pitting from rust though so it's never been of any concern to me.

[Belmont31R]

only fired 130 rounds.





Shoot more.....

[MarkG]

Is the bolt finished with manganese phosphate or black oxide? If it is pitting, more than just the finish wearing off, I'd be politely asking for a replacement.

[Miale]

those surfaces should be ground so it appears to be pitting - it will not effect function, it is purely cosmetic.

[MarkG]

those surfaces should be ground so it appears to be pitting - it will not effect function, it is purely cosmetic.

Seriously?

If the rings seal one side of the "terminus" what seals the other side if not proper clearance between the bolt and carrier? You don't think pitting may have an effect on proper operation of the weapon and lead to premature wear of the parts?

[Miale]

Seriously?

If the rings seal one side of the "terminus" what seals the other side if not proper clearance between the bolt and carrier? You don't think pitting may have an effect on proper operation of the weapon and lead to premature wear of the parts?

think about it,
the rings are the only seal in the system, the piting is below the surface, those two surfaces just ensure that the bolt is centered in the carrier, there will be no adverse effects on operation

[MarkG]

think about it,
the rings are the only seal in the system, the piting is below the surface, those two surfaces just ensure that the bolt is centered in the carrier, there will be no adverse effects on operation

I have though about it and you are two kinds of wrong. How can there only be one seal in a system that is "open" on two sides? The terminus of the gas system is sealed on one side by the bolt rings and on the other by the tail of the bolt and carrier. Pitting is unacceptable and it is a physical manifestation of poor quality. While the pitting may not have an immediate affect on operation, the long term reliability can certainly be called into question.

[BikerBCM]

Given the conflicting opinions on my issue I just emailed Bravo Company USA to see what they have to say. I would have prefered to talk with a person but they prefer email.

I will check back in with what they had to say as soon as I get a reply.

I see that their BCG's and bolt are all out of stock so if they want to replace it I dont know when that will happen...

Thanks for all the replies. Especially the replies that gave something useful instead of just saying use the search function.

BikerBCM

[Blankwaffe]

I believe that Grant commented sometime back that the rough pitted looking surface was an artifact of the phosphate process....or something like that.

Ive seen/had a few bolts from a couple different manufacturers that looked to be pitted all over and not just the bolt tail and bearing band(which highlight the rough texture as the high spots wear bright leaving the parkerizing in the pits).They were functional but when I sent a picture to the manufacturers they wanted them back for replacement.

That said and a interesting note,I also have a parkerized Remington 870 tactical that had the rough looking surface finish that continued to develop rusty spots all over even under a heavy film of CLP.Took it to a gunsmith friend and he said it was due to the phosphate salts not being rinsed off thoroughly.He disassembled the 870 and gave the parts a bath in Dawn dishwashing liquid and hot water,scrubbed with a nylon brush,rinsed with steaming hot water and then hosed it down with CLP.No issues since.

[Heavy Metal]

I think your 870 was a bead-blasted bluing.

Phosphate does not generate salts but is an acid.

[Blankwaffe]

I think your 870 was a bead-blasted bluing.

Phosphate does not generate salts but is an acid.

Nope....OD green parkerized.
Similar to:

http://www.remingtonle.com/shotguns/870synthetic.htm

http://www.remington.com/products/firearms/shotguns/model-870/model-870-express-tactical.aspx

Those are similar,but not the same.Mine is a earlier model(not a P) I picked up in 2006 that came with a standard synthetic stock(not the SpecOps),no receiver rail/sight(came with bead front only)or ported/Rem choke tube(mine is fixed imp cyl.).I believe some folks in the shotgun world refer to my 870 as a pre-P model from what I read.But it is parkerized.
I ran it through the Wilson Combat catalog for ghost ring and other goodness that was apparently not available from Remington at the time.

Im probably talkin out of the wrong side of my mouth as far as description,but how it was explained to me,again by the gunsmith....the acids in the bath are neutralized after the process and create salts.If the parts are not throughly washed to remove the salts they will act as reagents and hydrolyze=never ending corrosion as I experienced until properly washed.Im not a chemist, so others may be more exact in the detail.
But from what I understand this was an issue with some 870's that were parkerized a few years back when I bought mine.

[Dirtyboy333]

I have a BCM BCG that has about 100rds on it and it looks exactly the same. I think its normal and mine looked like that before i put any rounds on it.

Unless i'm not seeing what i'm supposed to in your pics then i wouldnt worry about it. My bolt "tail" looked like some1 used a scraper on it when it arrived in the mail. What i mean is the finish on the tail is gone compared to the rest of the bolt (is that what you were trying to show in your 1st pic?). I'm not worried about any of it but let me know if i should be.;)

ETA: The "chromish" look on the bolt tail is what i mean. Is that what pitting is? I think i'm probably missing what your pics are showing.