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Posted: 11/17/2003 4:41:59 AM EDT
My very first AR…(home built)
I went to the range Saturday to start braking in the barrel.  I was planning to put 20 or 25 rounds through it.  Here is how it went:
-I locked the very first round in, squeezed the trigger and nothing.  Just a “Clink” sound.
-I locked the bold back and looked in the chamber and the round was stock.  I managed to clear it out.  
-Locked a new round in and it fired.  
-Third round went “Clink” again.

This went on for about 20 rounds.  At one point, I managed to squeeze 7 rounds at ones before another round got jammed again.  I have no idea what the problem is.  
-Can it be the ammo I’m using? (Winchester 55g  FMJ ball ammo)
-Cycle timing problem?
-The bolt or firing pin?
Any suggestions will be greatly appreciated.  Thanks


Link Posted: 11/17/2003 10:15:14 AM EDT
[#1]

Hard to tell just what's going on with the info you provided. I assume what you're describing is a misfeed (?). Not sure exactly what you mean by "locked the first round in" or "the round was stuck" so you may be describing something entirely different.

If it's a misfeeding (won't feed the round properly into the chamber) problem, the easiest thing to do is try another magazine--one that is known to feed properly. If you're still having the same problem, and you're using factory ammunition (NOT reloads) go back to your assembly instructions and make sure all the parts are in the right place. Also, be sure to lube it properly.

After that, if the problem persists, get back and give us all the info you can.

Link Posted: 11/17/2003 7:18:23 PM EDT
[#2]
Drako,

Is the bolt failing to lock up, or is firing pin not striking the primer with enough force to ignite the primer?

Simple test is to charge the weapon, then give the forward assist a couple of blows to make sure that the bolt has fully lock, and try to fire the weapon.  If this allows the rifle to run for a single round, then you have a bolt/loading problem.  Also, you did remember to fully clean the rifle, including the chamber, before you fired the rifle.


On the other hand, if the bolt is fully locked, and the hammer striking the firing pin will not ignite the round, then it's time to check the hammer spring legs to make sure that they are on top of the trigger sides, and not below resting on the bottom of the receiver. If the hammer spring legs are in the correct location, and the fire control group is lubed, including the pins, then it time of check the firing pin for protrusion.  With just the bolt and pin, push the firing pin all the way into the back of the bolt, then Mic the amount of protrusion of the tip of the pin out to the face of the bolt.  It should Mic from .030 to .039.

Enough information for now, just get back to us when you can narrow the problem down too more than just a “click sound”.
Link Posted: 11/18/2003 3:55:12 AM EDT
[#3]
I believe the problem is that the firing pin is not striking the primer with enough force.  When I inspect the missed fired round, the primer does not show any nicks, indentations or scratches.

Note that I did clean the riffle and lightly lubed all parts.  I will give your suggestions a try this Friday and get back to you guys with my findings.  

Thanks much!

Drako  
Link Posted: 11/18/2003 4:16:30 AM EDT
[#4]
Quoted:
When I inspect the missed fired round, the primer does not show any nicks, indentations or scratches.  
View Quote


This means that the bolt is not fully locking up in the barrel extension (barrel lugs), and the back of the carreir is blocking the firing pin from reaching the primer to prevent a "Out of battery" ignition (read KB).
Link Posted: 11/18/2003 4:36:36 AM EDT
[#5]
Drako,
What make barrel are you using?

One of the kit suppliers had a bad batch of barrels, the chambers ended up getting slightly parkerized.  These barrels will never work untill the chamber is fixed.

Did you get one of these barrels?

The loaded round should drop freely into the chamber.  
Link Posted: 11/18/2003 5:34:24 AM EDT
[#6]
Quoted:
Drako,
What make barrel are you using?
View Quote


I used a custom Douglas blank.  It is a heavy barrel measuring 16’’
Link Posted: 11/18/2003 1:02:58 PM EDT
[#7]
Nope, not one of the parked chamber barrels.

Areas to check:

bolt cams smoothly in carrier

headspace with a "GO" gauge

Barrel extension alignment/timing

Burrs on bolt locking lugs

Proper buffer spring, make sure full length buffer assy has full length spring.


It really sounds like your bolt is not going all the way into battery.
Link Posted: 12/7/2003 3:26:39 PM EDT
[#8]
Looong shot. Verify you installed the disconnector spring. If its a double spring, replace with a single. If theres no spring...oh well.
Link Posted: 12/9/2003 7:48:23 AM EDT
[#9]
Ok… I took all your suggestions in consideration and took the riffle to my gunsmith.  We sat down in his shop and took the riffle apart.  Everything was built and assemble to specs.   We did replace the following:
-Buffer spring to a new full length one
-Brand new titanium firing pin (freebie)
-New HD extractor spring (freebie)

Took it out to the range the same day and “vualah” it worked perfectly
Put about 90 rds down range without a problem. Let me tell you, I still have that silly smile as I’m typing this message.  The thing is awesome!!! I really thing the new buffer spring did the trick.  

Thanks to all you for your input on this!

Drako
Link Posted: 12/9/2003 5:42:33 PM EDT
[#10]
By saying you installed the long spring, does that mean you had the shorty stock spring in a full sized stock, that would be weak.

Also go back to the steel firing pin.
That titanium free one will cause you problems some day.
Link Posted: 12/10/2003 4:20:13 AM EDT
[#11]
David,

The old spring was a full length. I did buy the entire stock assembly used at ebay.  Now it has the brand new spring.

Also, I can go back to the steel firing pin, but what sort of problems will I see with the titanium one?

Thanks
Link Posted: 12/10/2003 5:51:52 AM EDT
[#12]
Titanium pins have a reported tendency to be more prone to piercing the primer. When this occurs, the pin (at a minimum) has to be replaced. The normal steel pin is less prone to this and is more likely to survive a pierced primer.
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