What caused this?

[DMTJAGER]

Friend who moved almost six hours drive north of me to WI called me than emailed me this pic and asked me what I thought might have caused it. He just received in today's mail a new complete barreled upper assembly he recently bought on line from a maker of same. I sent him back what I thought might be causing the problem but didn't have much of an explanation as to why.
He told me he attached the new upper to a new lower of a different manufacture, installed the new BCG and charging handle, cycled the BCG and instantly heard what he felt was something scraping on something. He popped the pins removed the BCG and charging handle and saw what he sent me in the below pictures.

He said he went to his buddies house who owns quite a few AR-15's and he allowed him to barrow and tried three different charging handles and different BCG's both nitrite and phosphate coated as well as two different lower assemblies and regardless every time he cycled the BCG is scraped the roof of the upper.

Details:
Brand new never used or fired complete barreled upper assembly he bought from an on line supplier. Mated to a new complete lower assembly he bought from a different online supplier.
Picture of issue in question:
20210528_122357.jpg


I told him my best guess was the area at the very top end of the charging handle is some how making contact with and scraping the roof of the upper when he cycles the BCG. He also told me he is 100% positive he can see aluminum flakes from material being scraped off when he cycles the bolt deposited in the chamber on the lugs. I asked him if he could see any shiny points on the brand new charging handle that would indicate wearing from contact he replied no.
Obviously I told him he can not fire the rifle and it needs to go back to the manufacturer to be fixed. He also told me the M4 feed ramps are out of alignment as well.

He just wanted to know if I had any idea what could cause this so he could include that in his emails and conversations with the maker of the upper assembly. I said I had no idea and would post his picture and ask for help here.

I went and took my AR-15's apart and based on my deductions and the design of the upper and how and where the BCG travels when it cycles I'm reasonably certain the charging handle is somehow coming into contact with the roof of the upper and scraping off material.
I have also included a picture he sent me of both the misaligned feed ramps that also has the flakes of material in it that have been scraped off.

Ideas anyone?

[okie]

It almost has to be a clearance issue.

[AndyLate]

I would suggest your friend simply tell the vendor "The charging handle is dragging in the upper receiver and the feed ramps are grossly misaligned". They can mention a different CH and BCG were used to troubleshoot to no avail but, really, less is more when you contact the manufacturer.

As far as what caused it? Piss poor QC.

Andy

[bamashooter]

I would suggest your friend simply tell the vendor "The charging handle is dragging in the upper receiver and the feed ramps are grossly misaligned". They can mention a different CH and BCG were used to troubleshoot to no avail but, really, less is more when you contact the manufacturer.

As far as what caused it? Piss poor QC.

Andy

Yep..

[DG23]

I have also included a picture he sent me of both the misaligned feed ramps that also has the flakes of material in it that have been scraped off.

Ideas anyone?

I looked at the picture and they look aligned to me. What am I not seeing that you are?

They don't look like they have been 'blended' to the upper at all but they appear centered.

Would / could be worse if some dremel monkey had honked the heck out of them. Once gone that material can't be put back...

[Spooky1]

I would suggest your friend simply tell the vendor "The charging handle is dragging in the upper receiver and the feed ramps are grossly misaligned". They can mention a different CH and BCG were used to troubleshoot to no avail but, really, less is more when you contact the manufacturer.

As far as what caused it? Piss poor QC.

Andy

What this gentleman said.

[ST911]

Every AR I have has some measure of that CH/receiver wear developed over time. How much time varies, as does the particular CH.

A similar amount of ramp difference isn't uncommon in parts-house guns, and even a few okay guns. Better alignment is ideal. It will feed and function fine.

If it's not to his liking, by all means return it. Where did it come from, and whose manufacture is it?

[The_War_Wagon]

As far as what caused it? Piss poor QC.

That's as far RIGHT on "The Chart" as it gets - Oly/DPMS territory!

[DMTJAGER]

Every AR I have has some measure of that CH/receiver wear developed over time. How much time varies, as does the particular CH.

A similar amount of ramp difference isn't uncommon in parts-house guns, and even a few okay guns. Better alignment is ideal. It will feed and function fine.

If it's not to his liking, by all means return it. Where did it come from, and whose manufacture is it?

Thank you ST911 for your input and for your time spent to share it with me. Strangely enough he didn't tell me who made the upper assembly and I didn't think to ask, and I know the lower is an Aero Precision, after the problem arose he mated his new AP lower to his friends upper and confirmed the Aero Precision lower functioned without issue.

I openly admit I possess minimal AR-15 knowledge and all I know about AR's I have either learned as a benefactor of those such as yourself that are far more knowledgeable than I as in this instance and MANY others like it, who generously share their knowledge with me, or I learned by reading the more highly regarded books I own on care, maintenance, and gunsmithing of the AR platform.
I included the picture of the feed ramps as I didn't know if that could have been an indication of a alignment issue that also contributed to the clearance issue with the charging handle or as has been stated a result of P/poor QC.

Having said that I own a bunch of Ar-15's who's upper assemblies I purchased from three different but well enough regarded retailers, and lowers I also purchased from three different but also well enough regarded retailers (or would it be more correctly stated by saying well regarded assemblers of AR-15's) all mate to each other well enough to satisfy me and have worked well with essentially no issues. I also have never that I can recall had a fit issue with any of my charging handles or BCGs also from three different supposed manufacturers of same.

Once my friend contacted me and I saw his photos as a point of reference and to see if this issue is as serious as my instincts were telling me, I went and disassembled all of my AR-15's and NONE of the roofs of any of them had signs of wear anywhere near as severe or as limited to as small or specific an area as that in the picture my friend sent me. Also based on knowledge I learned here on how to avoid instances of FTF, FTE, ect that you should keep the areas of you upper and lower (chamber, BCG etc) reasonably clean and free from built up carbon and crud. Accordingly after every range session I seperate my upper and lower and as I get all I want of enviro friendly cans of fast evaporating parts cleaner for free from work I make a point to remove the vast majority of all crud and built up carbon from all areas of my upper and lower and as such I have never suffered a FTF/FTE but then again I never have put more than 300 rounds through a single one of my AR-15's in a single range day and do not ever let the barrel get to hot to touch.

Now I can not honestly say I've never found any metal shavings in my upper or lower while cleaning or inspecting other than the very very few ones I have found that obviously came form the ammunition, but I never recall having found any that appeared to be shavings of aluminum like the ones my friend claims he is finding. The individual round count on all my ARs is a minimum of 500+ (newest) and my oldest one has best guess without finding my record book on rounds fired about 5k and there wear from charging handles on the uppers isn't a fraction of or anywhere near that bad in such a limited and specific area and all of my feed ramps look to be well aligned or at the very least, visibly better aligned than the ones in my friend's AR as pictured.

But as I said I'm an AR-15 novice but I do know enough about firearms and machinery and how moving parts should interact with one another to know this level of wear on a brand new firearm after less than 60-70 cyclings of a part meant to move and cycle many 1000s of times over its life cycle is at the vary least unacceptable and a indication of a problem that needs to be fixed before the the firearm can be used for it's intended purpose.

If this were my complete upper I would be incontact with the seller and sending it back no exceptions. But unfortunately my friends knowledge of firearms, even most basic knowledge is no more impressive than his ability to heed good firearm advice. He is however an exceptionally successful DIY deer, elk, turkey and waterfowl hunter.

Thanks to all for confirming what I suspected was the cause of the problem but lacked the knowledge and experience to confirm it and at the same time increasing my education of the AR-15 platform.

I will repeat to my friend what I already advised him to do. Return the complete barreled upper assembly to the retailer, preferably for a refund.
Thanks again to the great members of this website.

[DG23]

That's as far RIGHT on "The Chart" as it gets - Oly/DPMS territory!

DPMS did not suck until Freedom Group came along.