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Posted: 4/16/2011 11:28:59 AM EDT
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Just got back from firing my ar for the first time. The first 15 rounds went flawless. After that it started to have feeding issues. it would eject but not chamber another round or it would strip the next round out of the mag but not get it chambered and pinch it half way. the round would not be locked into the bolt yet. the bullet of the round would be past the feed ramps started into the chamber. i have a couple of ideas of the problem. I only have 2 mags of the same brand. they are 20 round thermold mags. inexpensive at 7 bucks each. could it be these? i tried bolt mags same result. i tried only half loading them same result. I did put a tapco adjustable stock on it untill my a2 rifle stock gets to me. could it be this buffer and spring not letting the bolt come far enough back to strip the round out of the mag? I tried 2 different kinds of ammo remmington and federal. bolth 55 grain. Any ideas? Cant go back out to the range today....started raining.
Specs on my gun. j&t complete upper 24 inch bull barrel ported. chrome bcg areo percision lower double star lpk |
| picked up a mill spec steel mag with the green follower today a at local gun shop. payed to much in my opinion but it well help with the toubleshooting. if it ever stops raining/snowing i well try running the gun wet and try the new mag. ill let everyone know how it goes. |
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most feed problems I've seen are because of a crappy mag. Especially if you see it seating it halfway in and then pinching the round, it means the rounds tilting when it gets stripped. (Which also means that your rifle seems to be cycling properly) The only other thing I can think of that fits your description is if you have a M4 feed ramp on the extension but not on the barrel. |
| A milspec buffer spring will have about 37 coils to it. Check to see if a PMag will lock back after one round. You also might have too heavy a buffer. Put it on a scale and let us know what it weighs. Another thing to consider would be to put the cleaning brush on a drill and spin it around in the barrel extension. |
| Heres what i found out this morning. Ran a full 30 round mill spec clip. No malfunctions did not hold the bolt open on the last round. made it 5 rounds into the next mag when it jammed. Shell half in with the bolt on top of the round. Ran a heavy bead of gun oil down the bottom of the bolt and no malfunctions for the rest of the 25 rounds. This was pretty much how the rest of the 100 rounds went. Was a mixture of federal and rem umc 223 55 grain rounds. It was ejecting mostly at the 4 oclock position. i did notice 3 rounds or so before the misfeed it would slowly walk up to aprox 2 oclock. i well see if i have a scale that i can weigh the buffer. not shure that my powder scale goes heavy enough. the buffer spring in mine has 38 coils. The buffer is not marked and is gold in color. With shooting it today have ran 200 rounds through it. It has been cleaned before taking out every time. |
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37 coils? WTF does that mean without knowing the pitch as well? The buffer srping should measure between 10 1/16" and 11 3/4"
Quoted:
A milspec buffer spring will have about 37 coils to it. Check to see if a PMag will lock back after one round. You also might have too heavy a buffer. Put it on a scale and let us know what it weighs. Another thing to consider would be to put the cleaning brush on a drill and spin it around in the barrel extension. Do not "spin the brush in the barrel extension". Try some 30 rd pmags. ETA: Mags with green followers are shit. The jam you experienced is called "bolt over base" and is caused by the green follower tilting and allowing the case to drop below the bolt. For reference: If your bolt isn't locking back, your buffer is too heavy. Standard CAR 2.9 oz. H buffer is 3.8 oz. H2 buffer is 4.6 oz. Rifle buffer is 5.17 oz. 9mm buffer is 5.5 oz. H3 buffer is 5.6 oz. |
| my a2 butstock assembly finaly got to me on thurs. so i installed it. only had 10 rounds left so i went out and used them up. ran fine for all 10 rounds. im back to work for 2 weeks. when i get on days off again ill pick some more ammo up and let you know how its doing. |
| Did some more work on the rifle. Changed the butstock to a a2 trapdoor kit complete with tube spring and buffer. Ran 100 rounds through and it had 2 misfeeds bolt over base. Took it home and cleaned it. I then had enough money to pay off my scope so i put it on also. Whent back to the range to sight the scope in and ran another 100 rounds through it no misfeeds. I think we finally got that problem fixed! Only one more thing to sort out now. The bolt catch has never cought the bolt on the last round. Im starting to think its more the bolt catch spring than mags. I have tried 3 different mags and none have held the bolt open on last shot. All three work fine in a buddies ar. I have taken the lower off and put an empty mag in. the empty mag did not push the bolt catch up. I could push the bolt catch up and it would hold it up. Im thinking the bolt catch spring is to heavy. Any thoughts? |
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