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Old April 29, 2013, 01:57 PM   #1
IDT
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New Un-Fired AR-15 with a loading/extracting issue - Diagnosis?

Ok - So after finishing my AR-15 build the other day - the weather has been too crappy for me to go test fire it. However, I did load up a few magazines and run manual tests on the loading and extraction.

It FELT like everything was fine. However, as I was picking up the rounds off the floor, I noticed that EVERYONE of them had a new scratch on the bullet and on the case.



It's difficult to see in the photo as I'm trying to photograph with an iphone but there is a "stretched horse shoe" scratch on each bullet - I've outlined it in the photo below:



As you can see above, the scratch extends from the case to near the tip of the bullet the turns back around for a bit. EVERY SINGLE round that I chambered and extracted now has this mark.

Is this indicative of a problem?

Also, I noticed that it appears that my extractor is digging into the lip of the brass a bit too much as seen in the photo below:



Again, difficult to see so I've circled it here:



Now, I haven't made a practice of manually cycling rounds through an AR-15 before so that first scratch may be fairly normal - especially for an un-fired AR-15...I don't know. But that extractor nick has me a little worried.

EVERY round cycled perfectly fine manually - but those scratches have me a bit concerned.

Anyone have any idea what's causing them?
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Old April 29, 2013, 02:11 PM   #2
plouffedaddy
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Likely the feed ramps. It's normal; nothing to fret.
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Old April 29, 2013, 02:13 PM   #3
IDT
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Thanks.

I've put a LOT of rounds down range in ARs and Ms...but I don't make it a practice of inspecting rounds that were manually chambered and pulled...so I guess I just never noticed it before.
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Old April 29, 2013, 02:14 PM   #4
Robk
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Not to make light of your issue, but are you using the right ammo? No mention if your AR is chambered in 5.56mm or .223. There is a difference. 5.56mm will stick in a .223 chamber and my be causing your issues. The 5.56 is just ever so slightly larger, by thousands of an inch, but it does not fit a .223 chamber well is tolerances are tight.

so, to sum up

5.56mm will not work properly in a .223.

.223 will work properly in a 5.56mm.

I'm sure if this is not the problem, others more educated on this subject will steer you right.
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Old April 29, 2013, 02:22 PM   #5
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This is a 5.56 chambered REECE 1:8 AR....and the round was actually a .223

I grabbed a couple tracers in 5.56 that I have and did the same test - same results.

I can drop the rounds into the chamber with the bolt locked back and they slide in perfectly - and tipping the weapon up they fall out without any extraction necessary.
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Old April 29, 2013, 04:17 PM   #6
dogrunner
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I doubt that's feed ramp scratches, more than likely it's magazine lips that're leaving the marks.......the extractor marks are a bit harsh tho......are you using stock springs with the insert or the beefed up stuff that's marketed as necessary when it ain't?


If the rifle was mine, and I have built a bunch, I'd run a mag or so thru it and then start looking at both the mags and the extractor issues.......last gun I built was a RR with a 1/8 mid length, Wylde chamber,.......likely the most accurate one I have ever owned!
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Old April 29, 2013, 04:25 PM   #7
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Just ran a mag through it.
Seems that it doesn't leave the lip marks on the case when it's extracted with blowback.... odd...

guess everything is ok.
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Old April 29, 2013, 09:26 PM   #8
Dr Big Bird PhD
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When i first got done building my AR i had extraction issues too. 100 rounds fixed it. Sometimes they just need to be broken in.
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Old May 1, 2013, 09:43 PM   #9
Captains1911
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Normal. And it's gas operated, not blowback. Be very careful hand cycling live rounds, it's an accident waiting to happen.
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Old May 1, 2013, 10:17 PM   #10
Justice06RR
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^ yes, I would not recommend hand cycling more than just a couple of rounds.

When you have the time, just take it to the range and shoot it. If it fires and ejects fine, then you are golden.
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Old May 3, 2013, 06:29 PM   #11
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"5.56mm will stick in a .223 chamber"
I've NEVER seen this happen.
The bullet scratches are most likely caused by the bullet hitting the barrel extension and not really cause for concern. The ding in the rim is probably related to the sharp edge of the new extractor.
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Old May 3, 2013, 09:54 PM   #12
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Well, I broke the AR in today and the problem is no longer there at all!

I happen to have, on hand, about 2k rounds of 5.56 tracers - and I happen to live on a rather wet farm in the middle of nowhere. So, with my suppressor attached, I decided to do a bit of shooting.

All-in-all, I think it was about 400 rounds I ended up firing, with 95% being tracers. The can sure makes things much more dirty - but the NiB-x bolt just wiped off. That thing is amazing.

Anyway - fully aware that shooting tracers through a suppressor completely negates your "reduced signature" it was fun none-the-less. And I'm now much more confident in the weapon.

No FTF; no FTE - just smooth and fun.

Edit - and before someone says that I am ruining my barrel or my can:

Quote:
First off, want to establish credibility:

I am a Federal Firearms Licenced Manufacturer with an Special Occupational Tax Stamp (basically I can make surpressors and machine guns) and have been around firearms 30 years now. I went to Naval Gunnery School and have worked for a major firearms manufacturer (KAC). I have also fired tracing rounds (in the hundreds of thousands) of many different types (i.e. infrared and foreign military).

Why did I bring up this statement of credibility? Because I'm about to completely dispell some "misunderstandings" posted here about your tracer rounds.

I like the first post: It is entirely true that tracer rounds do not begin the burn until after they leave the barrel, typically between 25 and 75 yards. Because of this fact the only residue you receive in you barrel is gunpower and primer. With that said you should pay more attention to the type of primer you load into the weapon than the type of ammunition. Also, alot of countries put sealants on the projectiles such as tar or petroliuem which is more damaging than anything that tracer round is going to emit inside that barrel.

You will not hurt your barrel by sending a tracer round though it at all. Well, anymore than a regular round. The projectile does "grind in" carbon from preceding rounds, but you should know that the carbon that is present is much less dense than the steel the barrel is made of and therefore the reprocussions of such actions are minimal. This goes for ANY round. A tracer round is no more damaging than any other normal round.

Tracer rounds are illegal in some states. Which states I will not begin to list for fear of omitting one or two and therefore misleading you. I will say, that in Florida the tracer ammunition is illegal to fire, not own. So, yes and no to the legislative standing of ownership of tracer ammunition.

Just as a Post Script, I want to add that the year/type of the tracer ammunition does have bearing on the preceding statements. Older tracer ammunition (before the Korean war, and throughout) does have a tendency to ignite inside the barrel, but still typically has little impact.

To sum it up: Fire away.

T.A.
Found that online today - found several other sources that back that up.
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Old May 4, 2013, 08:45 AM   #13
madcratebuilder
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Quote:
Originally Posted by Robk
Not to make light of your issue, but are you using the right ammo? No mention if your AR is chambered in 5.56mm or .223. There is a difference. 5.56mm will stick in a .223 chamber and my be causing your issues. The 5.56 is just ever so slightly larger, by thousands of an inch, but it does not fit a .223 chamber well is tolerances are tight.

so, to sum up

5.56mm will not work properly in a .223.

.223 will work properly in a 5.56mm.

I'm sure if this is not the problem, others more educated on this subject will steer you right.
No sir. Some (heavy bullet) 5.56 can have a longer OAL that when chambered in a .223 'may' contact the barrel leade, but it's highly unlikely. For all practical purposes a 55gr .223 and a .55gr 5.56 are identical.

"leade"

1. That portion of a firearm's barrel immediately in front of the chamber where the bullet travels prior to contacting the rifling.
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Old May 4, 2013, 08:34 PM   #14
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