View Full Version : Malfunction diagnosis help
So I was out doing some shooting yesterday when this happened:
http://i75.photobucket.com/albums/i287/mtdawg169/2012-01-02_14-31-20_846.jpg
I was shooting Centurion .223 ammo, which is known to be relatively weak. The stovepiped case was trapped above the case head of another round which was partially fed into the chamber. Both rounds were trapped in place by the bolt. Tap, rack, bang did not clear the malfunction. I had to strip out the magazine, lock the bolt and get my fingers in there to clear it.
What are the typical causes of this type of malfunction and how is it best cleared?
Have you experienced this before? Has it happened with real quality ammo? I would default to the ammo (in this case) otherwise I would think that there is something with the ejector.
Have you experienced this before? Has it happened with real quality ammo? I would default to the ammo (in this case) otherwise I would think that there is something with the ejector.
IG, thanks for checking in. I have experienced short stroking issues with this ammo before in a different gun. No issues in this rifle with any other ammo, including federal xm193, m855, several flavors of Hornady & Black Hills, Guat m193, TAP practice, ae223 & pmc.
Looking more closely at that picture now, i'm wondering if the aimpoint cap may have caused an obstruction?
nineteenkilo
01-03-12, 16:17
Looking more closely at that picture now, i'm wondering if the aimpoint cap may have caused an obstruction?
That's the first thing I saw. I was going to ask if the cap hung there during the malfunction. Other than that - sounds like the ammo to me.
Always short stroke test when, and as soon as, possible after a malfunction.
Ejector is the usual culprit but I would put that scope cover somewhere else.
How to clear the stoppage: Some will simply slap the brass out, but this is not without risks. Sometimes the bolt may not lock fully or you may not have a round partially chambered.
Easy to remember is:
- if bolt is NOT closed
--lock bolt to rear
--mag out
--Work charging handle to clear chamber
--Reload
--Charge to chamber a round
--Gun up /Assess for threats
I'm sure others will have their preferences
Heavy Metal
01-03-12, 21:10
Roll the gun to the right when you tap, rack bang.
Roll the gun to the right when you tap, rack bang.
Except there is already a round in the chamber, TRB will cause a double or feed the next round into the rear of the chambered round.
Heavy Metal
01-03-12, 21:45
Except there is already a round in the chamber, TRB will cause a double or feed the next round into the rear of the chambered round.
But you don't know that till you try it. There may or may not be a round in the chamber. T(P-P)RB will successfully reduce about 80% of stoppages. That is why it is called Immediate Action. Following that would be Remedial Action, AKA a rip drill.
Generally speaking, TRB is something I am going to do on a pistol in a big hurry because if the rifle stops going bang, I am going to transiton to the pistol if within 25m or seek cover if not. I will un**** the rifle from a location of relative safety.
But you don't know that till you try it. There may or may not be a round in the chamber. T(P-P)RB will successfully reduce about 80% of stoppages. That is why it is called Immediate Action. Following that would be Remedial Action, AKA a rip drill.
Generally speaking, TRB is something I am going to do on a pistol in a big hurry because if the rifle stops going bang, I am going to transiton to the pistol if within 25m or seek cover if not. I will un**** the rifle from a location of relative safety.
I would respectfully disagree in the case of a stove-pipe. IME, there is usually another round partially of fully in the chamber. I am also not comfortable charging one round into the primer end of another if I can avoid it... but like I originally posted, others will have their own well thought out opinions on what is best.
IG, thanks for checking in. I have experienced short stroking issues with this ammo before in a different gun. No issues in this rifle with any other ammo, including federal xm193, m855, several flavors of Hornady & Black Hills, Guat m193, TAP practice, ae223 & pmc.
Looking more closely at that picture now, i'm wondering if the aimpoint cap may have caused an obstruction?
While the Aimpoint cap may have contributed to the malfunction, my first thought is it's an ammo issue like IG mentioned. I would move the cap and run some good ammo through the rifle and see if you have any other problems.
You can also examine the extractor and compare the spring to a new extractor spring to make sure it's not worn out.
While the Aimpoint cap may have contributed to the malfunction, my first thought is it's an ammo issue like IG mentioned. I would move the cap and run some good ammo through the rifle and see if you have any other problems.
You can also examine the extractor and compare the spring to a new extractor spring to make sure it's not worn out.
I will try it with different ammo to see if anything else manifests. This carbine has never had an issue in approx. 3k rounds. The centurion ammo has caused bolt over base / sort stroke malfunctions in another SR15 of mine. I just noticed the aimpoint caps after posting this picture. I recently swapped out the T1 mount from an ADM unit. Previously, the caps didn't ride quite so low when stored around the mount base.
Regarding clearance of the malfunction, TRB almost made it worse. Once I retracted the CH, it would no longer travel back all the way forward as the stovepipe case was in the way. The bolt sandwiced both cases in between the bolt face & the barrel extension.
Testing for short stroke would be the first logical step. Load a single round and verify the bolt catch is holding the bolt back after the round is fired.
If that checks out okay, I would detail strip and clean the bolt, paying attention to the ejector channel, which can occasionally become obstructed with debris. Check the ejector spring and ejector for unusual wear/damage. Make sure the extractor lip isn't rounded off. Check the extractor spring. Be sure it isn't soft, or an older rifle extractor spring with a blue insert. If in doubt, get a new proper carbine extractor spring (with black insert) such as a Colt (http://www.brownells.com/.aspx/pid=4840/sku=160-304-025/Product/Extractor-Spring-Assembly), BCM (http://www.bravocompanyusa.com/BCM-Extractor-Spring-Uprade-Kit-p/bcm%20extractor%20spring%20upgrade.htm) or Wolff (http://www.gunsprings.com/index.cfm?page=items&cID=2&mID=1&dID=79#492).
Testing for short stroke would be the first logical step. Load a single round and verify the bolt catch is holding the bolt back after the round is fired.
If that checks out okay, I would detail strip and clean the bolt, paying attention to the ejector channel, which can occasionally become obstructed with debris. Check the ejector spring and ejector for unusual wear/damage. Make sure the extractor lip isn't rounded off. Check the extractor spring. Be sure it isn't soft, or an older rifle extractor spring with a blue insert. If in doubt, get a new proper carbine extractor spring (with black insert) such as a Colt (http://www.brownells.com/.aspx/pid=4840/sku=160-304-025/Product/Extractor-Spring-Assembly), BCM (http://www.bravocompanyusa.com/BCM-Extractor-Spring-Uprade-Kit-p/bcm%20extractor%20spring%20upgrade.htm) or Wolff (http://www.gunsprings.com/index.cfm?page=items&cID=2&mID=1&dID=79#492).
Extractor & ejector check out fine & there were no other issues that day with that ammo. However, it has always exhibited weak ejection. I'm chalking this up to ammo for now unless I start seeing a more consistent problem. I've only got about 200 rounds of that ammo left, so I'll shoot it up and watch for issues with better ammo.
ForTehNguyen
01-04-12, 13:19
aimpoint cap shouldnt be there, asking for a malfunction with anything obstructing the ejection port.
TacMedic556
01-04-12, 14:00
Out of curiosity what is your barrel length, (carbine or middy), Buffer weight and action spring type? Is your extractor spring a 3, 4, or 5 coil? Do you use an "O" ring (I use a 5 coil and no "O" ring").
Also what magazines do you use?
The only time I have had short strokes was when I had cheaper HSM .223 ammo an H2 and Blue tactical spring in my 6920.
I am about 99% certain if you stop using that ammo, you will not have issues. If you are using M855, M193 or other known ammo and it happens, then yes there is another issue here.
Extractor & ejector check out fine & there were no other issues that day with that ammo. However, it has always exhibited weak ejection. I'm chalking this up to ammo for now unless I start seeing a more consistent problem. I've only got about 200 rounds of that ammo left, so I'll shoot it up and watch for issues with better ammo.
Out of curiosity what is your barrel length, (carbine or middy), Buffer weight and action spring type? Is your extractor spring a 3, 4, or 5 coil? Do you use an "O" ring (I use a 5 coil and no "O" ring").
Also what magazines do you use?
The only time I have had short strokes was when I had cheaper HSM .223 ammo an H2 and Blue tactical spring in my 6920.
The rifle is a complete SR15 with E3 bolt, standard usgi buffer spring and h buffer. There's no crazy buffer & wonder spring experimentation going on here. I'm chalking this one up to my initial theory of it being an ammo issue unless it starts happening again.
What i'm curious about at this point is the proper method to clear such a malfunction. Should remedial action usually clear it or is stripping the mag the only way this could be resolved? Maybe someone can point me to a good thread on malfunction types and clearing methods?
aimpoint cap shouldnt be there, asking for a malfunction with anything obstructing the ejection port.
This^ there was another thread somewhere same issue.
The rifle is a complete SR15 with E3 bolt, standard usgi buffer spring and h buffer. There's no crazy buffer & wonder spring experimentation going on here. I'm chalking this one up to my initial theory of it being an ammo issue unless it starts happening again.
What i'm curious about at this point is the proper method to clear such a malfunction. Should remedial action usually clear it or is stripping the mag the only way this could be resolved? Maybe someone can point me to a good thread on malfunction types and clearing methods?
You have already been given this information and from more than one person. Next range trip why don't you experiment yourself.
TacMedic556
01-04-12, 19:14
Dawg,
this might help:
An Operator’s View of M4/M4A1 Carbine (and AR-15 Carbine) Malfunctions
http://www.defensereview.com/an-operators-view-of-m4m4a1-carbine-and-ar-15-carbine-malfunctions/
as others have said and not to beat a dead horse, move that scope cap.
[/B]
You have already been given this information and from more than one person. Next range trip why don't you experiment yourself.
No need to get testy about it. Only two of you really addressed the malfunction & how to clear it. Most of the discussion has centered on the ammo & possible interference of the aimpoint cap. The two of you that addressed clearing the malfunction, had differing opinions. Hence my request for a more comprehensive discussion on malfunctions & clearance methods.
Dawg,
this might help:
An Operator’s View of M4/M4A1 Carbine (and AR-15 Carbine) Malfunctions
http://www.defensereview.com/an-operators-view-of-m4m4a1-carbine-and-ar-15-carbine-malfunctions/
as others have said and not to beat a dead horse, move that scope cap.
Thanks for the link. The cap is already gone. As I mentioned earlier, I recently switched to the KAC T1 mount from an ADM. The ADM has a larger base and made the cap ride higher above the ejection port. It never occurred to me that the new mount would cause an obstruction of the ejection port. Lesson learned.
The basic recognized method is to lock the bolt to the rear, clear the brass and rechamber another round. Or at least that is how I remember it. I can't remember the last time I had a real malfunction.
TacMedic556
01-04-12, 19:32
Dawg, I found the other article I was thinking of for you:
M4/M4A1 Carbine Reliability Issues Part II: Diagnosing the root cause.
http://www.defensereview.com/m4m4a1-carbine-reliability-issues-part-ii-diagnosing-the-root-cause/
It is more detailed explaining how to clear your stove pipe. Others have discussed it here as well. Hope it helps.
P.S. Your carbine looks good.
TacMedic556
01-04-12, 19:33
[QUOTE=TacMedic556;1187561]Dawg,
this might help:
An Operator
I don't get this post? :confused:
I don't get this post? :confused:
Sorry, operator error while posting from the phone.
No need to get testy about it. Only two of you really addressed the malfunction & how to clear it. Most of the discussion has centered on the ammo & possible interference of the aimpoint cap. The two of you that addressed clearing the malfunction, had differing opinions. Hence my request for a more comprehensive discussion on malfunctions & clearance methods.
Not getting testy...people disagree that is why I suggested you experiment yourself and see what works for you.
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