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Posted: 7/21/2009 5:01:10 PM EDT
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I have built a 16 inch middy kit from Del Ton with a Saber defence lower and after about 50 rounds it started fire when I pull the trigger and fire again when I release the trigger I have replaced the disconector spring and tired it again and the same thing after about 50 rounds it started double tapping again. Can anyone help with this
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Yep, disco is out of tune if the parts have been installed correctly, and you can either send the FCG back, or tune the one you have.
To tune the disco after you have checked to confirm that the disco spring is installed large coil down into the trigger slot (and not the problem), With the upper off the lower, pull the hammer all the way back with the trigger untouched, until you can get the hammer rear sear edge as close to the disco sear edge as possible. The free gap between the two should only be around .001 to .003 (thickness of a hair) with the trigger at rest. If the gap is greater than this, you will need to remove metal from the front bottom of the disco, where it seats/maxes out forward against the front top of the trigger. If you go this way, go slowly removing metal front the front bottom of the disco and check your progress often, since even a little metal removed from the disco will raise the disco forward at rest to close the gap quickly. |
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Yes, and the hammer spring legs should be on top of the trigger pin to retain it (not resting on the bottom of the lower receiver shelf).
If the trigger spring legs are installed on top of the trigger pin/ the spring is installed correctly (winds) and the pin is still walking out, then you either need to Knife edge the bottom of the spring legs so they stall in the annular grooves, or chuck the pins up and deepen/widen the groves so the spring legs fit the grooves correctly (so they stay in them). How the hammer spring should be installed (look at the direction of the winds). http://www.ar15.com/forums/topic.html?b=3&f=66&t=241858 |
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Quoted:
Yep, disco is out of tune if the parts have been installed correctly, and you can either send the FCG back, or tune the one you have. To tune the disco after you have checked to confirm that the disco spring is installed large coil down into the trigger slot (and not the problem), With the upper off the lower, pull the hammer all the way back with the trigger untouched, until you can get the hammer rear sear edge as close to the disco sear edge as possible. The free gap between the two should only be around .001 to .003 (thickness of a hair) with the trigger at rest. If the gap is greater than this, you will need to remove metal from the front bottom of the disco, where it seats/maxes out forward against the front top of the trigger. If you go this way, go slowly removing metal front the front bottom of the disco and check your progress often, since even a little metal removed from the disco will raise the disco forward at rest to close the gap quickly. I have this problem but I never fired a round through it yet. I noticed it when checking at the point of install. Why would he have been able to fire 50 rounds through and then have the problem? It seems like it would have started on day one. Also, can you explain the point of the disconnector? Is it simply to make sure that it does not go full auto? If the disconnector would not engage then the depressing the trigger would result in full auto fire? |
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Production bur on the edges of the sears (back of trigger or disco) would be enough to allow a out of timed disco to retain the hammer at reset, and once the burs broke off, cause problems with retension of the hammer on the disco when the bolt slams home, which releases the hammer while the disco while the trigger is still help back. With the trigger pin falling out, the same thing happens since the disco is not retaining the hammer full strength as the B/C crashes/jolts home.
If the rifle did not have a disco, then on some rifles, the hammer would wedge on the bottom of the carrier (L cut hammers with un-shrouded carriers). On round top hammers or carrier with shrouded carriers, then the hammer just follows the carrier back forward (rides the back of the carrier), and the firing pin is not struck hard enough to ignite most primers as the bolt locks home. |
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