UPDATE: CONFIRMED ISSUE WITH DD BARREL...Oddmarks on the brass...UPDATE WITH NEW PICS

[84wh1]

I finally got around to shooting my MK18 I built using colt receivers, BCG (new never fired, still in blue bag when I got it) and DD 10.3 barrel. Anyways, first round loading failed to feed but otherwise it ran as it should. When I was collected my brass at the end of the day, I noticed that they all had the same marks. Any idea what it's from? When the first round failed to feed, the case got caught up on the feed ramps. Ran only Pmags and Winchester white box. The dummy rounds I tested when I got home left the same marks. I also noticed some inconsistant wear in the upper (which prob isn’t anything related) Anyways, see pics for reference.

 

[Gunnerlove]

They are getting scuffed on extraction. First rule of gun camp is barrel length matters.

 

[84wh1]

They are getting scuffed on extraction. First rule of gun camp is barrel length matters.

My factory DD mk18 (same barrel, gas system, buffer weight as my Colt mk18) doesn't do this.....

Also my dummy rounds were getting scratched in the same fashion (as seen in the pics) when I manually cycled the bolt. That should mean that barrel length has nothing to do with this.....

 

[r34skyline]

I finally got around to shooting my MK18 I built using colt receivers, BCG (new never fired, still in blue bag when I got it) and DD 10.3 barrel. Anyways, first round loading failed to feed but otherwise it ran as it should. When I was collected my brass at the end of the day, I noticed that they all had the same marks. Any idea what it's from? When the first round failed to feed, the case got caught up on the feed ramps. Ran only Pmags and Winchester white box. The dummy rounds I tested when I got home left the same marks. I also noticed some unusual wear in the upper. Anyways, see pics for reference.

View attachment 278377View attachment 278378

Are you referring to where the bcg rides in the receiver and the finish starting to come off? Lube the bcg well and carry on. As for the marked brass is your chamber clean?

 

[84wh1]

Are you referring to where the bcg rides in the receiver and the finish starting to come off? Lube the bcg well and carry on. As for the marked brass is your chamber clean?

Yes that's correct however I've never seen wear as inconsistent as this in the receiver. Instead of straight smooth wear, it's spotty and random. The BCG is very well lubed. Not my first kick at the can in the AR game. Lol

As for the chamber yeah it was clean. This was a new build.....

 

[r34skyline]

Yes that's correct however I've never seen wear as inconsistent as this in the receiver. Instead of straight smooth wear, it's spotty and random. The BCG is very well lubed. Not my first kick at the can in the AR game. Lol

As for the chamber yeah it was clean. This was a new build.....

Possible poor anodizing on the receiver leading to premature finish wearing off. Admittedly it has more rounds than this gun but mine is starting to show similar wear. If it runs ok i say keep running it. Is the cam pin slot wearing normally?

As for the brass marks if it's doing that while you are manually extracting i would check your feed ramps if the chamber is good. It's dragging at a specific spot. Hard to tell in the pic is the case deforming/denting or is it just the surface thats scratched up?

 

[84wh1]

I suspect the marks on the brass has to do with feeding as the first round ever loaded into the gun jammed up on the feed ramps and when I extracted it, the marks on the brass were identical to the marks left from the spent cases. Being that the barrel is DD 10.3 and receivers are Colt, I didnt suspect any problems. To the bare eye the ramps looks nice and smooth and clean. I mean, it ran fine and all however I just wasnt expecting anything of this nature. Im gonna have to spend more time to look things over and diagnose exactly whats causing this. Thanks for your response.

 

[r34skyline]

I suspect the marks on the brass has to do with feeding as the first round ever loaded into the gun jammed up on the feed ramps and when I extracted it, the marks on the brass were identical to the marks left from the spent cases. Being that the barrel is DD 10.3 and receivers are Colt, I didnt suspect any problems. To the bare eye the ramps looks nice and smooth and clean. I mean, it ran fine and all however I just wasnt expecting anything of this nature. Im gonna have to spend more time to look things over and diagnose exactly whats causing this. Thanks for your response.

No problem. Keep us posted. I am curious what caused this.

 

[cancer]

I would recommend taking a sharpie and drawing little lines on the cartridges. One at 3,6,9 and 12 O'Clock, be sure to label them. Then load the round into your mag with 12 facing up. Cycle the action and see exactly where the scratching is happening. That'll help narrow things down to start.

 

[84wh1]

UPDATE: Issues with DD barrel

So I finally had time to spend with this rifle to do a better inspection. I had loaded rounds into the chamber and manually extracted this. Doing this results in NO marks. When I load the rifle in the designed method using a magazine, the scratches occured. This indicated that it's definately happening during loading.

Anyways I took a good look at the chamber area and compared it with my factory complete DDMk18. The colt MK18 (using a DD 10.3 barrel) has a noticable difference in the way the chamber is chamfered when compared to the complete DD rifle. The colt has much more pronounced sharp lines at the chamber while the DD is obviously smoother. Anyways I've attached some pics. I've emailed wolverine and Daniel Defense earlier this week but still haven't heard back. I believe the brass is scratching hard on the chamber edge during loading as it's not chamfered the same as the DD rifle.

 

[84wh1]

well I sent the pics to wolverine and filled out a warranty claim. Time will tell.

 

[84wh1]

So my upper got sent to wolverine. Sure enough, the chamber on the factory DD 10.3 was sh!t. I guess someone at DD quality control was sleeping. Anyways the gun Smith at wolverine polished it up under warranty and is mailing it back to me.

I emailed my displeasure to Daniel defense. A factory 10.3 DD barrel should have not been sent out like mine was. I mean, this isn't NEA.

 

[srdiver]

I would have painted a round with Engineer Blue and see where the transfer is....

 

[PGW Steve]

It will be rubbing on the sharp edge at the chamber. The arc of contact on the case is too large to be anything else.

 

[84wh1]

It will be rubbing on the sharp edge at the chamber. The arc of contact on the case is too large to be anything else.

Thanks steve. Thats what I had figured and sure enough, Wolverine confirmed this and polished things up for me. Still not terribly pleased though that a DD barrel left the factory this way but its what it is. lol

 

[Sinasta]

Thanks steve. Thats what I had figured and sure enough, Wolverine confirmed this and polished things up for me. Still not terribly pleased though that a DD barrel left the factory this way but its what it is. lol

DD QC has been going down hill for awhile. They still make good guns but not at the prices they are asking. My older version MK18 had chips off the anodizing on the brass deflector from the factory. Not sure how much test firing you need to start chipping the brass deflector.