Abmormal wear on CMMG Banshee .45acp upper

[Member 34319]

Im not trying to argue dude. I can see what you are saying. I'm just attempting to state it is normal wear. Zoom in on my picture and you will see mine is completely rounded off. Probably after the first couple of thousand rounds too. From that point on I imagine no additional erosion occurred. Your gun will wear in. Your ejection port will likely look like mine in time.

This is normal on all AR15s with plunger style extraction.

All in all, none of this affects function either, so it's basically cosmetics. Normal cosmetics wear be that.

 

[JuglansRegia]

Are you shooting steel cased ammo?

 

[ZA_Survivalist]

You could always just put a piece of something like the black rubber flex tape or a small piece of a Talon grip tape over it and change the tape out every few thousand rounds or as needed?

Exactly what I was thinking. It'd solve the problem asap.

 

[oregunbob541]

Are you shooting steel cased ammo?

Nope... all brass

 

[Alexx1401]

Nope... all brass

In that case it will never be able to do real damage. From what others are showing it's the way it is. If it's something you can't live with now would be the time to ask CMMG to just replace the gun, then sell it new, or put it up for sale as is. For me as long as it worked 100% is all that would matter to me but then NONE of my guns stay anything close to pretty. If they will not take the gun back, maybe they would replace the part on the upper? Then try to sell it. Bummer I know but sounds like this is just the way these things work. I have a couple PCC's AR's but mine use a different kind of ejector so do not seem to beat that part up.
1st pic is a Foxtrot Mike upper, you can see they put a beefy piece there to protect from the brass. Second is an Upper I have no idea who made. Came from 5D who makes jigs and don't think they mentioned who they buy them from but you can see the heavy cut out for the brass to miss. Hope you can work out something that will make you happy with the gun as they are some damn nice PCC's they make.

 

[Member 34319]

Watch were the case hits first. Imagine a shorter fatter case instead.

 

[Member 34319]

In that case it will never be able to do real damage. From what others are showing it's the way it is. If it's something you can't live with now would be the time to ask CMMG to just replace the gun, then sell it new, or put it up for sale as is. For me as long as it worked 100% is all that would matter to me but then NONE of my guns stay anything close to pretty. If they will not take the gun back, maybe they would replace the part on the upper? Then try to sell it. Bummer I know but sounds like this is just the way these things work. I have a couple PCC's AR's but mine use a different kind of ejector so do not seem to beat that part up.
1st pic is a Foxtrot Mike upper, you can see they put a beefy piece there to protect from the brass. Second is an Upper I have no idea who made. Came from 5D who makes jigs and don't think they mentioned who they buy them from but you can see the heavy cut out for the brass to miss. Hope you can work out something that will make you happy with the gun as they are some damn nice PCC's they make.

View attachment 708914 View attachment 708915

Most blowbacks have a fixed ejector. The case hits that, and for the most part goes straight out the port without touching anything.

 

[Ops]

maybe use a heavier buffer. you using hot handloads?

 

[Alexx1401]

Most blowbacks have a fixed ejector. The case hits that, and for the most part goes straight out the port without touching anything.

Yes both of mine have the fixed one that is bolted into the lower. Have a hand full of 80% lowers and all of them use that same ejector. I did have one break which came as a shock. One day gun would not work at all. Got it home and ejector was gone. I thought it had fallen out at first as the part the bolts in was gone. Put a new one in and all was fine. Later I found the top half of it and the bottom half in the range bag. So damn thing had broken. Hopefully just a 1 off since it's never happened again.

 

[oregunbob541]

I'll take it out and shoot it some more and see if it gets worse. CMMG did say they'd replace the upper as this much wear with a low round count isn't typical.

 

[oregunbob541]

maybe use a heavier buffer. you using hot handloads?

Factory 230 grain fmj ammo...remington, winchester white box and magtech... some S&B jhp too

 

[Iceman04503]

My banshee 45 does that. I have about 800-1000 rounds suppressed thru it. Yes, its dirty, I need to clean it.

I have a banshee 9mm with roughly the same amount thru it and it does not have those marks.

 

[JuglansRegia]

If it has a standard AR-15 type ejector, you can clip a turn or two off that plunger type ejector spring. It will either make it better or make it worse. Otherwise, all I can say is that these kind of problems are normal with firearms that haven't gone through a lot of R&D, field testing, revisions ect. We are kind of spoiled with AR-15's because they have been around for so long most of the kinks have been worked out. Once you get into the two types of AR10 platforms then you start having problems again.

 

[terdog]

My CMMG 10mm has zero wear at about 1K rnds.

I have had similar "wear" on my DW Valkyrie 9mm. DW said that its normal and would stabilize. I didn't like their response as none of my other 1911's had that wear.
It did stabilize.

I'm no gunsmith. But take them up on the replacement offer. Or change out the buffer spring or the weight?

My Brigade BM-9 ( both Fostech & std) had an update. They added a buffer spring spacer, which I believe increased the buffer spring tension.

Got these from Amazon. 4 for $19. They are a foam type material. They may help you.

 

[bfoosh006]

Normalish... but as mentioned you can alter your ejection pattern. And clearly dependent on your buffer weight , recoil spring and cartridge used... as mentioned by various posters.

FWIW.. my 9MM Colt pattern PCC uses a .308 Tubbs recoil spring, and a 7.5oz buffer... in other words you can tune your pistol to better suit your needs.

Most AR firearms use parts that allow function under a variety of conditions and ammo. So there will be "combo's of parts that allow positive function "compromises"... luckily we can adapt those parts to fit our needs.

The fuzzy side of velcro trick will help. Cut pieces to fit.

I do it to all my AR's, no biggy for aesthetics to me... much more about chasing brass all over the place.

What weight is your buffer ? And heavier buffer weight will "slow" the vigorous ejection.... as will a heavier recoil spring. Your results will be different compared to mine , because mine is straight blowback... yours is delayed blowback.

Cutting a coil from your ejector spring would possibly help as well. Be sure to have a spare ejector spring on hand in case the results aren't what you want. DO this last, if needed.

I would also check, ( first ) the claw on your extractor... if it has sharp ends, it is most likely gripping the fired cases rim longer / vigorously... and not allowing "easy" roll out, release of the fired case.

From the interwebz...


So.... If this pistol was mine. And not knowing your mechanic abilities ( no offense at all , it is the internet )

DO THIS FIRST....I'd check the ends of the claw on the extractor. Smooth JUST the pointy ends, if needed allowing a smooth release / roll off. A sharp ended claw might be gripping the case until contact with the case deflector.

Consider a stronger recoil spring... maybe a Tubbs 5.56 Flatwire recoil spring.

Consider a heavier buffer weight.
Both these will "slow" the cyclic speed.

And as a last resort, clip a coil from the ejector. AGAIN last resort... since the ejection , while not what you want, is still happening properly.. as in getting out of the receiver.

Edit... just stumbled across this... CMMG MKG Bolt Maintenance Kit - Ejector Spring, Extractor, etc. - .45ACP

 

[terdog]

bfoosh006 ,

All sage advise with 1 exception.
Doin some of those mods may invalidate the warranty.
I would suggest letting the factory foot the bill and spend the time tryin to get it right before takin a shot at makin it better.

But, thats just my way of thinkin.

 

[bfoosh006]

bfoosh006 ,

All sage advise with 1 exception.
Doin some of those mods may invalidate the warranty.
I would suggest letting the factory foot the bill and spend the time tryin to get it right before takin a shot at makin it better.

But, thats just my way of thinkin.

In full agreement...

I just like tinkering. And would rather fix it myself, more of a learning how to DIY

 

[Bencisn]

I bought a CMMG 10mm not too long ago, has about 1200 rounds through it. It's all chewed up. I sent a bunch of pics to CMMG and they said keep an eye on it. I'm eventually going to have it replaced under warranty, the amount of wear and damage from basic range time is out of control. Always standard, brass load (180 grain), always well maintained and lubed after each session.

These photos are just after 200 rounds.

 

[oregunbob541]

Dang that's way worse than my .45. They replaced my upper under warranty with what they called their new "hardened" upper receiver. I'm not sure what the difference is with the metallurgy, but they said it should be more resistant to this type of wear. I havent had a chance to shoot it yet since I got it back. What I did for a little bit of preventative maintenance was take a bit of rubber Talon grip material and put it on the brass deflector and in the little armpit by the ejection port. Hopefully that helps protect it a little bit.

 

[Bencisn]

Dang that's way worse than my .45. They replaced my upper under warranty with what they called their new "hardened" upper receiver. I'm not sure what the difference is with the metallurgy, but they said it should be more resistant to this type of wear. I havent had a chance to shoot it yet since I got it back. What I did for a little bit of preventative maintenance was take a bit of rubber Talon grip material and put it on the brass deflector and in the little armpit by the ejection port. Hopefully that helps protect it a little bit.

Good to know they're willing to support their products. How does it work with a replacement under warranty? Do you have to send it in first, then wait for the replacement to land at FFL, and then wait forever for background check?