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Posted: 2/14/2009 12:22:02 PM EDT
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hey guys i posted this in the discussions on accident.
i recently put a double star lower below my stag arms m4 upper. i went out to the range the other day and noticed when i went to load the first round it got stopped when it was going up the m4 feed ramps. i just pushed the forward assist and all was good. i noticed it happens every now and again and sometimes if there is a round in the chamber and you pull on the charge handle it feels stuck. you have to pull a little harder and it will pop loose and eject the cartridge. i loaded a mag and loaded a cartridge in the chamber. i pulled back on the charge handle and cycled some ammo through it. if you racked it the ammo would load fine. once in a while the cartridge would get "stuck" and you would have to pull harder on the charge handle to eject it. any ideas? oh forgot to mention that the ammo that i ran through it also had slight marr marks caused from the feed ramps. |
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With 500 rounds fired, and True extended feed ramps (read in the upper receiver as well), the problem lies in either the B/C binding/lack of recoil spring tension, the mags in question have burs on the bottom of the feed lips, or the mags not being retained high enough in the receiver for a clean feed when being hand charged.
Since the rifle does run fine when self cycling, then the biggest suspect item would boil down to the recoil spring, since a weak spring would allow the buffer to be sling shot off the back of the receiver extension, and gain the addition speed to self feed more reliably than the first charging. Run of thumb is a carbine spring should be around 10.5", while a full stock spring around 11.75". If you find your spring less than this, or the kit was a low budget one, a new quality spring may be the ideal thing to solve such. |
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Borrow someone else's carbine spring the next time you are shooting and see if the other spring solves the problem.
Without a tension gauge, could be that the spring is just a shortened full length spring, and not the correct wire diameter to get the correct shorter spring tension weight. |
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