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007Kevin
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Posted: 3/21/2012 5:37:25 PM
When I go to clear my rifle at the end of a rifle 3gun stage I have had to pull back on the charging handle while giving a butt stroke against a hard object. Does not seem to have problem any other time.

JP15 factory upper - 223 wylde chamber
Factory xm193 ammo - checked with JP case gauge and within spec
Chamber gauges found chamber to be in spec - closes fairly easy on 556 go gauge, does not close on 556 no go.
Use D&H mags with magpul followers and pmags

I have changed my cleaning procedure and cleaned my chamber with a chamber brush and using power drill - use Shooter's Choice solvent and mobile 1 oil
I saw moderate improvement with this but still had the problem last weekend at a match.
(my other rifles I have never cleaned the chamber with a chamber brush including my LaRue Stealth which has a 223 wylde chamber and never had this problem)

TIA
SharpCharge
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Posted: 3/21/2012 7:12:30 PM
Could it be your extractor?
007Kevin
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Posted: 3/21/2012 11:55:39 PM
Wouldn't the round just get left in the chamber when pulling back on the CH and butt striking the rifle on the ground at the same time?

Rifle has maybe 500 rds through it
SharpCharge
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Posted: 3/22/2012 12:34:20 AM

Originally Posted By 007Kevin:
Wouldn't the round just get left in the chamber when pulling back on the CH and butt striking the rifle on the ground at the same time?

Rifle has maybe 500 rds through it

Good point, I guess I had a brain fart on what the issue is.

So let's try this again... lol, what grain bullet are you using in these matches? Is it factory loaded or reloads? Is there a chance the OAL is too long causing the bullet to seat too far into the chamber and actually engaging the rifling?
Gamma762
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Posted: 3/22/2012 12:56:58 AM
[Last Edit: 3/22/2012 1:13:07 AM by Gamma762]
Originally Posted By 007Kevin:
223 wylde chamber

Needn't have posted anything else. Problem has nothing to do with headspace.

A Wylde is a target chamber, designed with the leade/throat area in front of the case mount cut to .224" - the same diameter as the bullet. Just had another thread on the Wylde chamber tonight, and posted several informative links there: http://www.ar15.com/forums/t_3_4/568070_wyldie_chamber.html

Depending on the ogive and seating depth of the bullet in question, some bullets will start to engrave into the throat when chambered (others will be very close to doing so). That .224 interference fit is good for precision, since the bullet is completely controlled from the moment it starts moving forward from the case, but bad for user-friendliness because you can't easily eject a live round. There is a lot of mechanical disadvantage in the extraction sequence on an AR15, so it's very tough to overcome that friction when extracting a live round from the chamber. Empty case ejection is not effected at all.

Solutions are: change barrels, shoot more to get a little throat erosion to relieve the interference fit. If it's an unlined/untreated steel or stainless barrel you could have the chamber recut to something with a slightly larger throat. Couple of other options depending on how much trouble you want to go to.

If you don't believe me, after you do the buttstock-slam ejection, take a look at the bullet... about 1/16" to 1/10" in front of the case mouth, you will see a ring around the bullet where it's been pressed into the freebore. Different styles of bullets that have a different shape may be slightly narrower there and will eject normally. XM193 was one of the tightest fitting ammo that I found when I ran into this problem.
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USMC2147
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Posted: 3/22/2012 1:18:12 AM
Originally Posted By Gamma762:
Originally Posted By 007Kevin:
223 wylde chamber

Needn't have posted anything else. Problem has nothing to do with headspace.

A Wylde is a target chamber, designed with the leade/throat area in front of the case mount cut to .224" - the same diameter as the bullet. Just had another thread on the Wylde chamber tonight, and posted several informative links there: http://www.ar15.com/forums/t_3_4/568070_wyldie_chamber.html

Depending on the ogive and seating depth of the bullet in question, some bullets will start to engrave into the throat when chambered (others will be very close to doing so). That .224 interference fit is good for precision, since the bullet is completely controlled from the moment it starts moving forward from the case, but bad for user-friendliness because you can't easily eject a live round. There is a lot of mechanical disadvantage in the extraction sequence on an AR15, so it's very tough to overcome that friction when extracting a live round from the chamber. Empty case ejection is not effected at all.

Solutions are: change barrels, shoot more to get a little throat erosion to relieve the interference fit. If it's an unlined/untreated steel or stainless barrel you could have the chamber recut to something with a slightly larger throat. Couple of other options depending on how much trouble you want to go to.

If you don't believe me, after you do the buttstock-slam ejection, take a look at the bullet... about 1/16" to 1/10" in front of the case mouth, you will see a ring around the bullet where it's been pressed into the freebore. Different styles of bullets that have a different shape may be slightly narrower there and will eject normally. XM193 was one of the tightest fitting ammo that I found when I ran into this problem.


^^^This. It is just tight and hasn't broke in enough yet. Keep shooting it and it should loosen up. If you want, try not cleaning the chamber area as often it may help.
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007Kevin
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Posted: 3/22/2012 1:50:29 AM
[Last Edit: 3/22/2012 1:54:43 AM by 007Kevin]
Please read original post.

That said, Wouldn't fouling create a smaller diameter in the chamber??? It seemed to be more of an issue when not cleaning it.

But essentially keep shooting the gun. I should buy 223 ammo for comps and shoot 556 for practice.

ETA - This does not happen with my LaRue Stealth which is also a 223 Wylde. Whats the story here?
Gamma762
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Posted: 3/22/2012 4:18:21 AM
Some may not be using a true Wylde chamber design, or they may be stretching the throat out to a longer length.

Chamber brush does not extend into the throat area, that will only be cleaned along with the rest of the bore. Fouling can indeed tighten that up a little.

223 vs 5.56 is irrelevant. It has nothing to do with the pressure the ammo is loaded to. Only thing that matters is the ogive shape of the bullet, the seating depth in comparison to your chamber, and if you have fouling in there.
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Dano523
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Posted: 3/22/2012 10:14:04 AM
Dry fit the carrier without bolt into the upper to confirm that the gas tube did not get bent during a jam,and is now not correctly indexed with the carrier key.
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007Kevin
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Posted: 3/22/2012 1:11:35 PM
It is definitely not a carrier key/gas tube issue.

What is weird is that I didn't have the issue going to the range and shooting or in the first couple 3gun matches I used it in.
Gamma762
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Posted: 3/22/2012 5:56:44 PM
As I mentioned before, different ammo types or even different lots of ammo may vary but just a tiny amount, enough to either have the bullet touching or just change the amount that it's touching the throat.

If you eject a live round that "sticks" I'll bet you will see something that looks like this on the bullet:

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007Kevin
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Posted: 3/24/2012 12:03:20 AM
Originally Posted By Gamma762:
As I mentioned before, different ammo types or even different lots of ammo may vary but just a tiny amount, enough to either have the bullet touching or just change the amount that it's touching the throat.

If you eject a live round that "sticks" I'll bet you will see something that looks like this on the bullet:

http://muzepix.com/ar/pics/wylde.jpg


I see a tiny bit. Not that pronounced. PMC 223 seemed to run fine today. Actually talked to JP himself today and said to try a different bolt if I have one and I should send the rifle back to them.
USMC2147
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Posted: 3/24/2012 2:03:23 AM
Originally Posted By 007Kevin:
Please read original post.

That said, Wouldn't fouling create a smaller diameter in the chamber??? It seemed to be more of an issue when not cleaning it.

But essentially keep shooting the gun. I should buy 223 ammo for comps and shoot 556 for practice.

ETA - This does not happen with my LaRue Stealth which is also a 223 Wylde. Whats the story here?


Sorry It was late and I didn't really explain my thinking here. What I meant to say was as you shoot it more with build up in the chamber, it would produce a smaller opening, but may have enough grit to help wear it in. I see they are willing to take care of you, which is good. Let us know how this pans out for you, good luck.
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afroney
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Posted: 3/26/2012 3:03:41 PM
Originally Posted By Gamma762:
As I mentioned before, different ammo types or even different lots of ammo may vary but just a tiny amount, enough to either have the bullet touching or just change the amount that it's touching the throat.

If you eject a live round that "sticks" I'll bet you will see something that looks like this on the bullet:

http://muzepix.com/ar/pics/wylde.jpg


Never thought of that. My LMT MRP would do just that - Lock up when extracting a round by hand, but cycle just fine when shooting.

Problem eventually lessened after shooting a few cases of Brown Bear through it. Replaced the barrel recently and the problem went away.
sully
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Posted: 3/26/2012 9:36:46 PM
There are many things that can cause casings to stick. Do you have a pic of the stuck casing that you can post, as it may help give us an indicator as to what occurred? Give the rifle a good thorough cleaning, especially the chamber and barrel. Make sure that all fouling (to include copper) has been removed, and then thoroughy swab out the chamber with denatured alcohol to remove any solvent or lubricant, then try it again and see what happens.


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