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Posted: 5/13/2006 6:53:26 PM EDT
| hi all got a new bushmaster 14.5 in HB flat top with a car lower, and at any given time the rifle will go full auto for 3-5 rounds, i haved tried all types of ammo,factory new and reloads, changed out my bolt assembly with a bushmaster new one that i have, and the rifle still does it! any ideas? the rifle is only 3 weeks old its kind of fun but it sucks also if you try to shoot for a good group thanks for any help mike b |
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Disco problem, Chances are either the disco spring is installed canted/missing, the parts are binding, or just some production crap in the FCG that is not allowing the parts to work correctly. You’re going to need to pull the FCG, so lets just get to it. With the upper and lower receives separated, use a punch and drive out the hammer pin from the receiver. This will allow you to pull the hammer out. Next push the trigger pin out and pull the disco/trigger from the receiver. Now with just the trigger in hand, inset the pin (either one since both are the same) into the trigger and make sure that the pin rotates freely. If the pin does not rotate freely, then check the ends of the trigger channel for burs (if burs are found in the sides of the trigger holes, then use a small file or stone and remove them). Next take a look at the disco spring in the trigger (rear slot). The large coil side of the spring goes down, and should be fully seated in the slot. Now install the disconnector into the trigger and install the pin. The disco should rotate freely (will have spring tension). If the disco binds, then check the inside of the trigger channel and the sides of the disco for burs (read break out the file/stone is any are found). From this point, Clean and lube the parts, then reinstall them in the receiver, making sure that the hammer spring legs are on top of the trigger pin when completed. From there, the simple function test once the rifle is reassembled it to just hold the trigger, lock the bolt back on the bolt catch, then hit the bolt release and let the carrier slam home. On the impact, the trigger/disco should retain the hammer (remember you are holding the trigger back all during this, so the hammer is being retained by the disco only). Once the carrier slams home, release the trigger, then pull it. The hammer should fall on the re-pull after release (read not during the carrier slamming home). Here is a link just incase you get lost on pulling the FCG, http://www.ar15.com/content/guides/assembly/lower/ |
Normally I would agree with you, but sooner or later he will need to pull the rifle down and give all the parts a good cleaning (read one blown primer and he will need to pull the parts to dig it out). Granted that the FCG shouldn't need to be pulled from the start, but unless Bushmaster agrees to pay shipping both ways, and he can live without the rifle for a few weeks, the problem (if binding/production debris) is a 5 min fix, and gets him one step closer to understanding the rifle as a whole. If after the pull/reassembling of the cleaned/lubed FCG parts the rifle still has problems, then it's time for it to go back to bushmaster to be corrected. |
| Dano523 that's what I will do I will tare down the (FCG) first check it clean and lube it and check the springs and the spring tension. Friday bushmaster told me that it would be a repair time of about 6 weeks, they are busy, the person at bushmaster also seems to think that the problem is in the (FCG) as well, I copied your tare down procedure and will do mine today! thanks much!! mike b |
| dano523 hi i took my 14 inch and switched my lowers with my 16 inch lower, so i went shooting, i shoot 200 rds and had no full auto problems, i have not had time to take the 14 inch lower apart yet, so at least i know that the problem is in the 14 inch lower. Soon i will dissamble (FCG) to see what the problem is i will check back to let you know thanks for the ideas and help mike b |
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