First time out w Combat Armory upper

slsc98 · Dec 2, 2021

Question.

Is it normal - or completely unheard of - to find some fine metal shavings inside the upper receiver after the first couple boxes of ammo, through a brand new complete upper mated onto a brand new complete lower?

So, this is the first time I’ve bought a complete upper assembly (Combat Armory) and slapped it onto a complete lower (PSA) and, after a first or initial 40 rounds, found some fine metal shavings (look to be both aluminum or steel AND a couple brass) inside the upper receiver?

After returning home from range, I used mineral spirits and compressed air to flush what’s in the pics out of the disassembled rifle after 2 boxes of factory Federal 55gr soft point (zeroing at 50yds - 5 shots to zero red dot and 5 more to zero opens - and then play with some steel at 200 (30 shots) …

slsc98 · Dec 2, 2021

I’ll add, the rifle functioned flawlessly with those SHK mags from Global Ordnance (those mags run slick as snot through everything we own) and I’m happy with accuracy from 50-yards with open sights …

I’d already zeroed the 4moa dot sight which was turned off in order to zero the open sights which are some non-spectacular Tippmans and, thanks to GrayStone Eye Clinic in Hickory that 3/4” paster WAS THE TARGET at 50-yard, from seated at bench using elbows …

Dang it. All pics should be rotated 1/4 clockWISE … !

teratos · Dec 2, 2021

slsc98 said:
Dang it. All pics should be rotated 1/4 clockWISE … !

If you have an iphone, the fix is to edit the pic and change the size ever so slightly. They then display correctly.

slsc98 · Dec 2, 2021

Ahhhhhhh …. dang, Thank you!

Now about those metal shavings?

ETA: tried it on my iPad no love, will try and mess w it on my iPhone after I crawl out from under hon’s rear axle …

Arcamm · Dec 2, 2021

Just curious if you cleaned and lubed it before firing?

teratos · Dec 2, 2021

Check the rear of your carrier for burrs. The buffer shouldn't be that chewed up. I'd bet thats where the metal is coming from. If that isn't it, close the lower on the upper slowly. The rear of the carrier should push the buffer back a little. The buffer should not contact the buffer retaining pin during the firing cycle. If it doesn't push the buffer back off the pin a little, the lower is out of spec.

slsc98 · Dec 2, 2021

Arcamm said:
Just curious if you cleaned and lubed it before firing?

Excellent question and yes, insides and outs, thoroughly. :thumbsup:

teratos said:
Check the rear of your carrier for burrs. The buffer shouldn't be that chewed up. I'd bet thats where the metal is coming from. If that isn't it, close the lower on the upper slowly. The rear of the carrier should push the buffer back a little. The buffer should not contact the buffer retaining pin during the firing cycle. If it doesn't push the buffer back off the pin a little, the lower is out of spec.

Thank YOU! :thumbsup:

Imagunna do these checks just as soon as get done working on wife’s car…

Ponder_MD · Dec 2, 2021

teratos said:
Check the rear of your carrier for burrs. The buffer shouldn't be that chewed up. I'd bet thats where the metal is coming from. If that isn't it, close the lower on the upper slowly. The rear of the carrier should push the buffer back a little. The buffer should not contact the buffer retaining pin during the firing cycle. If it doesn't push the buffer back off the pin a little, the lower is out of spec.

Teratos- How common are problems like this with home builds?

I'm looking to purchase an HBAR upper kit soon and mill my 80% lower this winter.

GuitarmanNick · Dec 2, 2021

That is a lot of shavings, not normal, and you should be able to see what is wearing based upon your pictures.

Did you clean it well before firing? Is it possible a clump of shavings left over from manufacturing was in the upper and overlooked?

Look for sharp edges near the feed ramps and the bolt face which may be tearing up the brass.

Are any of the shavings sticking to the receiver? Hard to tell from the pictures. Thinking possible contamination during the anodizing process and shooting it has freed them due to wear.

Hope you get it figured out.

teratos · Dec 2, 2021

Ponder_MD said:
Teratos- How common are problems like this with home builds?

I'm looking to purchase an HBAR upper kit soon and mill my 80% lower this winter.

I've seen the burr on the carrier once. These are not common issues. Get decent lowers (I like Cerro Forge, they have the keyhole forge mark). The only problem I have had with home builds is the safety sometimes being too close to let the trigger pull sufficiently, and won't engage as a safety. A file fixes that. I'm sure folks have other issues, but if you start with good stuff, you'll get a good rifle. Most “issues” will be human error.

Arcamm · Dec 2, 2021

slsc98 said:
Excellent question and yes, insides and outs, thoroughly.

Then I'm with teratos, I'll bet you have a burr somewhere that's still machining your rifle.

slsc98 · Dec 2, 2021

GuitarmanNick said:
That is a lot of shavings, not normal, and you should be able to see what is wearing based upon your pictures.

Did you clean it well before firing? Is it possible a clump of shavings left over from manufacturing was in the upper and overlooked?

Look for sharp edges near the feed ramps and the bolt face which may be tearing up the brass.

Are any of the shavings sticking to the receiver? Hard to tell from the pictures. Thinking possible contamination during the anodizing process and shooting it has freed them due to wear.

Hope you get it figured out.

Hey, Nick!

Yes, I cleaned the upper REALLY WELL - as in used a pan with mineral spirits, a natural bristle brush and compressed air to flush the dang thing out with a vengeance - as it compared very “dry and rough” compared to the DelTon’s.

I’m going to take your advice and go through it, the bolt carrier group, EVERYthing with a pair of OptiLoupe visors on once I:

a) get the wife’s 66 GTO figured out (was thinking the rear axle was low on gear oil but checked that and now I’m thinking the clutch needs adjustment which is outta my bailiwick :-( AND THEN

b) figure out why I’m not getting any cocking in the Glock 23 I dropped a Lone Wolf trigger upgrade kit into last night (from 1-3am :sad20:

) (Looks like the connector is sitting out away from the trigger assembly chassis a good bit; I’ve got a message left into them now …

I have to admit, while I did inspect the bolt face closely I did NOT examine around the feed ramps …

GuitarmanNick · Dec 2, 2021

Forgot to mention to check the extractor for burrs, too. It needs to have a sharp angle, just not digging into the brass as it functions.

Any burrs should be lightly dressed with a fine file or stone.

slsc98 · Dec 2, 2021

GuitarmanNick said:
Forgot to mention to check the extractor for burrs, too. It needs to have a sharp angle, just not digging into the brass as it functions.

Any burrs should be lightly dressed with a fine file or stone.

Thank YOU, Roger Wilco!

SkiPatrolDude · Dec 2, 2021

Looks like some interesting cam pin wear on the inside of the upper. Some wear/peening in that area is not uncommon, especially if the buffer is too light causing premature unlocking, but I have not seen it in that specific area on any rifle before.

Inspect your cam pin on the BCG. Any indication of rubbing?

Also, what buffer weight are you running?

slsc98 · Dec 2, 2021

teratos said:
Check the rear of your carrier for burrs. The buffer shouldn't be that chewed up. I'd bet thats where the metal is coming from.

Check. Rear of carrier looks okay (but, I’ve yet to go through the entire action area with magnified vision and I’m gonna wait til I have no interruptions and do that with purpose)

teratos said:
… If that isn't it, close the lower on the upper slowly. The rear of the carrier should push the buffer back a little. The buffer should not contact the buffer retaining pin during the firing cycle. If it doesn't push the buffer back off the pin a little, the lower is out of spec.

Whew. The rear of the carrier is definitely moving the buffer back a little. (Did I say, “whew!” ? )

I really appreciate your and the others’ replies. While I was replying to GuitarmanNick the UPS driver arrived with another DelTon upper (the one in question is a Combat Arms) and I haven’t had any issues with those thus far, like the one I am looking for the cause of now …

teratos · Dec 2, 2021

That's the extent of my knowledge!

slsc98 · Dec 2, 2021

SkiPatrolDude said:
Looks like some interesting cam pin wear on the inside of the upper. Some wear/peening in that area is not uncommon, especially if the buffer is too light causing premature unlocking, but I have not seen it in that specific area on any rifle before.

Inspect your cam pin on the BCG. Any indication of rubbing?

Also, what buffer weight are you running?

Hi, SkiPatrolDude - and Thank You. I am going to inspect the cam pin extremely closely when I get home and go through the entire upper with magnifications and “finger tips”.

I am clueless as the the weight buffer PSA sent the lower with, I, ASSuming milspec weight?

Maki · Dec 2, 2021

My Yugo Mauser has that problem. The feed ramp has a sharp edge on it and shaves off the brass. Since it mostly sits in the safe, I've never bothered to file it down smooth as it only gets maybe 10 rounds a year through it.

slsc98 said:
b) figure out why I’m not getting any cocking in the Glock 23 I dropped a Lone Wolf trigger upgrade kit into last night (from 1-3am ) (Looks like the connector is sitting out away from the trigger assembly chassis a good bit; I’ve got a message left into them now …

I bought a Pyramid trigger from Glockstore and had the same problem when I built my Poly80 G17. Tested the slide with a stock G22 to make sure it wasn't a slide issue, and ended up trashing the trigger for OEM (About $180 gone because it was outside of return window due to COVID parts delays). Overall it seems that aftermarket triggers may have tighter tolerances than stock which may cause issues with the trigger connector lowering enough to release the striker. Of course, that was with a Poly80 build and not an OEM Glock...If you've got the OEM Trigger, I'd toss that in to see if it works like that or not.

slsc98 · Dec 2, 2021

teratos said:
That's the extent of my knowledge!

Yours extends farther than mine so, now that we have that settled, I’m pulling my “knowledge pants” back up now … :lol2:

First time out w Combat Armory upper

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