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Posted: 4/10/2006 11:06:27 AM EDT
[Last Edit: 4/10/2006 11:07:48 AM EDT by skerbo]
Whenever I eject an unfired round from the chamber, for whatever reason, I see that the bullet is gouged and scratched enough to where you can feel the scratch with your fingers. I assume this gouge is being put there by the feed ramps when the round is chambered. I assume that this could greatly affect the accuracy of the weapon, especially when using soft point ammo seeing as how the lead will take a deeper gouge. So anyways, is there anyway I can fix this, by polishing the feed ramps or something similar? I am even open to the possibility that it's not what I think it is, so if anyone has any suggestions or knows the cause and knows how to fix it, I would be greatful to hear it.

Thanks for any info.

ETA: This is a new rifle (2006 SEBR), my first AR, and has less than 1000 rounds through it.
Link Posted: 4/10/2006 11:10:29 AM EDT
Just shoot it, don't worry about the scratches as their probably getting on the bullet during the "ejection" cycle.

Mike
Link Posted: 4/10/2006 11:17:38 AM EDT

Originally Posted By mr_wilson:
Just shoot it, don't worry about the scratches as their probably getting on the bullet during the "ejection" cycle.

Mike



I had considered that. I will do some experimenting to see what actually causes it, the chambering or ejecting.
Link Posted: 4/10/2006 11:17:54 AM EDT
it may be from the mag too
Link Posted: 4/10/2006 11:19:13 AM EDT

Originally Posted By skerbo:
.. I assume this gouge is being put there by the feed ramps when the round is chambered.
... I assume that this could greatly affect the accuracy of the weapon,



Too many asumptions, not enough hard data (and I VERY much doubt the scratches were put in by the feed ramps).

Are you having feeding or extraction issues with your AR?

Do you have any accuracy issues?
Link Posted: 4/10/2006 11:23:12 AM EDT
if they are short and wide scratches or long and skinny scratches then i vote magazine issue. I've noticed a couple times that the mag lips (when new) can mar the casings a bit.
Link Posted: 4/10/2006 11:24:25 AM EDT
[Last Edit: 4/10/2006 11:26:12 AM EDT by skerbo]
There are consistency issues. I am not too proud to rule out operator error, but the scratches do kind of make me wonder. Either way I'm trying to rule out one variable at a time.

ETA: When I get home I'll cycle a few rounds while eagle eyeing the chamber to see if I can find the cause.
Link Posted: 4/10/2006 11:36:26 AM EDT

Originally Posted By Forest:

Originally Posted By skerbo:
.. I assume this gouge is being put there by the feed ramps when the round is chambered.
... I assume that this could greatly affect the accuracy of the weapon,



Too many asumptions, not enough hard data (and I VERY much doubt the scratches were put in by the feed ramps).

Are you having feeding or extraction issues with your AR?

Do you have any accuracy issues?



+1... It could possibly be an out of spec magazine or sharp lugs gouging the bullet...
Link Posted: 4/10/2006 12:50:55 PM EDT
Hey whaddaya know? I posted the same question a little while ago. The general consensus was that I shouldn't worry about it, so I didn't.

www.jobrelatedstuff.com/forums/topic.html?b=3&f=66&t=268384
Link Posted: 4/10/2006 4:27:21 PM EDT
I've also noticed this. The ramps on my 2005 SEBR are very sharp.

It would be a very interesting experiment for someone with the tools/knowhow/materials to build some sort of feedramp polisher. Maybe a couple 1" diameter wire brushes on a special tool you could power with a drill.
Link Posted: 4/10/2006 4:58:54 PM EDT
Things usually smooth out with use. Shoot it to death.
Link Posted: 4/11/2006 2:40:10 AM EDT
Much ado about NUTHING here, your rifle ain't no toy, quit playing around with it and simply shoot the rifle.

You'll find these scratches your worrying your head over don't mean shit and have no effect on accuracy.

Cycling live rounds proves nothing, besides it ain't safe, real problems surface while shooting the rifle.

Mike
Link Posted: 4/11/2006 8:07:01 AM EDT

Originally Posted By mr_wilson:
Much ado about NUTHING here, your rifle ain't no toy, quit playing around with it and simply shoot the rifle.

You'll find these scratches your worrying your head over don't mean shit and have no effect on accuracy.

Cycling live rounds proves nothing, besides it ain't safe, real problems surface while shooting the rifle.

Mike



It is a tool, AND a toy. Although I take good care of my firearms, I don't cry over wear or scratches on the finish. I didn't really expect to get lectured over, I am just a new AR owner and was wondering if this was a problem or not. None of my other rifles or handguns have the same problem, so I thought it might be common to the AR-15.

Anyways, I think Rabon is probably right and with more shooting the problem will fix itself, and I consider myself educated on the issue.

Thanks
Link Posted: 4/11/2006 8:19:00 AM EDT

Originally Posted By mr_wilson:
Much ado about NUTHING here, your rifle ain't no toy, quit playing around with it and simply shoot the rifle.

You'll find these scratches your worrying your head over don't mean shit and have no effect on accuracy.

Cycling live rounds proves nothing, besides it ain't safe, real problems surface while shooting the rifle.

Mike



+1
Link Posted: 4/11/2006 9:03:55 AM EDT

Originally Posted By skerbo:
Whenever I eject an unfired round from the chamber, for whatever reason, I see that the bullet is gouged and scratched enough to where you can feel the scratch with your fingers. I assume this gouge is being put there by the feed ramps when the round is chambered. I assume that this could greatly affect the accuracy of the weapon, especially when using soft point ammo seeing as how the lead will take a deeper gouge. So anyways, is there anyway I can fix this, by polishing the feed ramps or something similar? I am even open to the possibility that it's not what I think it is, so if anyone has any suggestions or knows the cause and knows how to fix it, I would be greatful to hear it.

Thanks for any info.

ETA: This is a new rifle (2006 SEBR), my first AR, and has less than 1000 rounds through it.



I just ran into this same situation with a new Bushmaster barrel assembly that I put on one of my ARs.
The locking lugs near the feed ramps were very sharp and had small burrs on them. I took an emery board and a dremel stone and smoothed them out then sprayed the entire area down with carb cleaner to flush out any abrasive residue. It took a while to do it but it worked. I also deburred the locking lugs on my bolt(the leading edge that makes contact when the bolt rotates into a locked positiion). I sprayed it with BreakFree and then took it out and fired 1000 rds through it to break it in. It functions flawlessly and no more scratches. Very accurate too.

I do not understand why manufacturers don't bead blast this area smooth and deburr it in the manufacturing process.....it might take all of 15 seconds to do.
Link Posted: 4/11/2006 10:07:26 AM EDT
[Last Edit: 4/11/2006 10:09:02 AM EDT by A_Free_Man]
Once again, Armalites's Tech notes is your friend:

www.armalite.com/library/techNotes/tnote17.htm

"TECHNICAL NOTE 17: MARRING OF CARTRIDGE CASES
GENERAL: Cartridges fired in AR-10 and M16 family firearms bear characteristic scratches and marks which shooters sometimes think indicate defects.
FACTS:


"The following scratches and marks are typical with ArmaLite patent firearms, from a variety of manufacturers, and do not indicate defects:

"1. Light scratches along the length of the cartridge body. Caused by contact with magazine feed lips or another cartridge during feeding.

"2. Two dents and related scratches on neck. Caused by neck striking 2 locking lugs during extraction. The Ejector forces the case to the side, causing the contact.

"3. Random circumferential scuffing of body. Caused by case brushing past chamber mouth during feeding.

"4. Dent on case body or mouth. Caused by case contacting upper receiver during ejection.

"5. Circular mark on edge of base, with shiny brass or shaved brass in evidence. Caused by case being pressed into ejector hole, with some burnishing or cutting as the bolt rotates.

"6. Scratches or slight rim deformation opposite #S. Caused by extractor snapping over rim, and the energy applied during extraction.

"7. Light protrusion of primer metal around the firing pin strike (cratering). Caused by clearance between the firing pin and firing pin hole; varies depending on primer hardness and cartridge pressure.

"Other marks, including heavy machine marks pressed into the brass, or repeated case failures or primer punctures, can indicate a flaw in the rifle or use of reloaded ammunition. Contact ArmaLite if you experience problems."

Send your note of thanks for such a fine library of AR info to Mark Westrom at Armalite.
Link Posted: 4/11/2006 11:10:07 AM EDT

Originally Posted By A_Free_Man:
"The following scratches and marks are typical with ArmaLite patent firearms, from a variety of manufacturers, and do not indicate defects:

"2. Two dents and related scratches on neck. Caused by neck striking 2 locking lugs during extraction. The Ejector forces the case to the side, causing the contact.



Though I'm talking about the bullet itself and this article is talking about the shell casing, this particular item could pertain to the bullet if it was still in the casing. It could be caused by extraction, not chambering.
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