Stuck Live Round

[SMM123]

I have a factory Double Star AR 6.5 Grendel. For sighting in purposes, I was using Wolf ammunition which fed and fired fine (other than blowing primers out.)

When I switched to the Hornady (#8150) factory ammunition, the rounds were failing to fully seat and would stick in the chamber/barrel. It required mortaring to get the round loose, at which point the case came free from the bullet, which was left lodged in the barrel. This happened multiple times with various magazines from various manufacturers.

When I seated a single round by hand and let the bolt free, the round seated and fired normally, with complete ejection. This was the only way I could get any of the Hornady ammunition to fully come to battery and fire.

Upon inspection of the Hornady brass and unfired bullets, there were deep parallel gouges on both. The expended Wolf brass also had the parallel scratches, though not as deep (no bullets to inspect as they all fired.)

It appears that the feed ramps are gouging the bullet and brass to the point that it jambs in the chamber when fed from the magazine, whereas the hand-fed rounds did not exhibit any issues. Why the WOLF did not have similar problems, I have no idea.

At this point, do my feed ramps need to be reworked/polished? Or is there some other issue I need to be aware of?

[LRRPF52]

First, I would recommend stopping immediately if you see blown primers. That is a dangerous sign of over-pressure, and could lead to a catastrophic malfunction involving fragmentation of the upper receiver outwards. Something is seriously wrong.

If you then experienced failure to go into battery with the Hornady, that would be a good time to stop again and diagnose the system.

Detailed pics would be helpful, but it sounds like something is way out of whack here.

[bwaites]

Wolf blown primers are unusual, because that is a fairly mild load.

Time to take a "TIME OUT" and talk with Doublestar. They generally do a good job, and I've not heard similar issues.

Time for more questions!

[SMM123]

To maybe address the blown primers issue, I was shooting suppressed out of a 20" heavy barrel (bull under the hand guard and .750 from the gas block to the end.) Less than 10% of the Wolf rounds were blowing the primers.





In the next two photos, you can see a long scratch on the bullet, which was from when it was inserted the first time to take pictures of the bullet.

[SMM123]

The damage



In the following photo, you can see a second scratch above the more visible one. This was from the second insertion for the photos above.

[VASCAR2]

I have a 16" 6.5 Grendel J&T Distrubuting which is the component side of of Double Star. My cartridges would get all scratched along with the brass. I think the scratches on the bullets was coming from the sharp edges of the barrel extension where the bolt lugs lock into place. Through firing the bullets are not getting near as scratched as when new. The scratches on the brass appeared to be from the sharp lips of the mags and the bolt/carrier moving over the top cartridge during the firing cycle.

If your having feeding problems I'd suspect defective or improperly formed mag feed lips. C Products and ASC mags seem to have more issues than typical 5.56 mags. I found I needed to clean my ASC mags as there is a gummy preservative from the factory. Since cleaning the ASC mags have functioned 100 %. If your using a suppressor, this can affect dwell time and cycle timing.

It's your decision as to whether to send your rifle back to DS. I have talked to them a couple of times and they had good customer service.

[LRRPF52]

Shooting with a suppressor changes everything, especially your cyclic rate. It is best controlled with an adjustable gas block, otherwise you have a violent cycle of operations, often leading to FTFeed and FTExtract malfunctions.

This is what I do to barrel extensions to alleviate most of the edges on the barrel extension feed side:

[SMM123]

This is what I do to barrel extensions to alleviate most of the edges on the barrel extension feed side:

So, how is this accomplished?

[ricsmall]

Smm123

Most guys use a dremel with cratex polishing wheels, but having a $600ish barrel, I went the manual route. Find a small dowel or round rod and wrap sandpaper around it starting with 600 and working to 800,1000,1500,2000. These papers can be found at auto paint suppliers. If you can find a tapered rod it works better. A 5.56 case tapped on the bottom for a 1/4" bolt would probably work great. Just work slowly and take short, even strokes. I don't have pictures, but I never have scratched or gouged brass. Also, polish the inside edges of the feed lips on your mags. Those babies will gouge brass pretty deep. Disassemble mag and try to put a SLIGHT bevel on the inside edge of the feed lip. Again, work slowly. Hope this helps

Richard

[mongoosesnipe]

there should be no reason why wolf factory would feed and hornady not that said suppressors are filthy animals, awesome but dirty i would suspect your chamber was filthy by the time you started shooting the hornady also you need to check your firing pin protrusion for the blown primers

[SMM123]

there should be no reason why wolf factory would feed and hornady not that said suppressors are filthy animals, awesome but dirty i would suspect your chamber was filthy by the time you started shooting the hornady also you need to check your firing pin protrusion for the blown primers

It doubt it was a dirty chamber since I could manually feed rounds by hand, and they would drop in place and come to full battery without any issue. The problem only occurred when being fed from the magazines (it didn't matter which I used AA, Stoner, ASC, C-Products, it occurred with all of them), and then only with Hornady.

[noone]

In your first picture of the inside of the upper receiver/barrel extension, there is something at about 4 o'clock relative to the barrel extension. Is that dirt, a crack, manufacturing flaw, or just an unknown bit of junk in the receiver?

If it is a crack, I would wonder if it contributes to any of the phenomenon you describe.

[explorecaves]

In your first picture of the inside of the upper receiver/barrel extension, there is something at about 4 o'clock relative to the barrel extension. Is that dirt, a crack, manufacturing flaw, or just an unknown bit of junk in the receiver?

If it is a crack, I would wonder if it contributes to any of the phenomenon you describe.

not sure what you are talking about but it appears to either be a fiber or a shadow depending what I think you are referencing....

[SMM123]

In your first picture of the inside of the upper receiver/barrel extension, there is something at about 4 o'clock relative to the barrel extension. Is that dirt, a crack, manufacturing flaw, or just an unknown bit of junk in the receiver?

If it is a crack, I would wonder if it contributes to any of the phenomenon you describe.

Most of what can be seen in the chamber area is propellant and other residues, left from when the case separated from the bullet during mortaring. There are no cracks.

[sureshot]

The lines on the case are made from the sharp edges on the feed ramp/lug combination. you need to polish those parts and the lines will go away. They will go away with use but mark up your brass