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Posted: 3/21/2003 6:31:22 PM EDT
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I just got a pre-ban pwa ar that had been in someone's closet collecting dust since about '91. It's my first ar. I opened it up and cleaned it out. Had some oil coating all internals and barrel so all are bright and shiny after cleaning. Bolt seems to work freely. Took it to the range and had two problems. First there was significant vibration after each shot. Is this normal? This is a 16'' car model, however, it is wearing a full a2 buttstock right now. Could the vibration be a buffer/spring problem? I have a new buffer and spring and I might try swapping out to see if it helps. I assume you just remove buttstock, unscrew tube with wrench from end and insert new spring and buffer, right? Second, every other shot or so would fail to strip off of the magazine and insert into the chamber all the way. Sometimes the round would get most of the way into the chamber and could be inserted completely using the forward assist, but generally the round would fail to leave the mag completely. I tried several colt GI mags and had the same problem with each, so that's probably not it. How do I fix these problems? I'm frustrated and feel like just buying a new m4 type upper but really can't afford it. |
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Rather new at this myself, but I may be able to help you with your first problem. I might add, the vibration may not be a problem in itself, but is the nature of the beast. To remove and replace the buffer and spring one does not have to remove the stock. Push out the take down pin in the receiver and pivot the upper down. Look rear toward the buffer and note the detent in the six o'clock position of the buffer tube hole. Push down on the detent while holding back a little on the buffer, then allow the buffer to be pushed out by the spring. As far as your second problem, have to hope someone with a little more know how comes along. |
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Feed problem could be one of two problems. 1. You may have the wrong buffer/recoil spring in the rifle. The Car stock uses a shorter spring than the standard long stock. 2.Your carrier may be binding up on the forward stock. This carrier bind could be caused by the hammer tail being to long and the hammer jamming in between the disconnector and carrier. The other thing that we see a lot of is the hammer catching on the firing pin on the forward stroke. To figure out what may be binding, hold the trigger, clock the rifle and slowly ride the cocking handle forward, you will feel the bind. Let us know if it's the firing pin or the hammer tail that is too long and we can help you solve the problem. |
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Dano is right on about the CAR-length spring. Sounds like the bolt is not getting enouigh forward impetus, all right. Is your buffer the short one or the longer one? If it's less than 4" or so, the vibration could be caused by the bolt-carrier key impacting the top of the lower, where the buffer tube threads on. I saw a pic on the board here awhile back, titled "OMG, My Rifle Broke In Half!!" that I'm sure had a cast frame and a carbine-length buffer in a full-length tube. Pull your bolt carrier and check the back of the carrier key for peen marks. If you see any, DON'T SHOOT the rifle until you get the proper buffer!! Be careful, Be SAFE, and Good Luck! |
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There are the different types of buffers. If you have the long A-2 stock on the rifle, then you use the long standard buffer and spring. If you have a Car stock on the rifle, then you use the standard Car buffer and the shorter CAR spring. [url]http://www.biggerhammer.net/ar15/buffers/[/url] The first buffer is a Car buffer; the second is a buffer for an A-2 stock. But!!!! Even when you have the correct buffer and spring in the rifle, the buffer will still make a sprong noise. It is the buffer spring retracting back over the buffer and past the receiver extension walls (tube). If you are hearing a clack noise like a direct metal-to-metal contact, the chances are you have the wrong buffer in the rifle. As for a trigger job, you best bet is to just buy a Rock River arms two-stage trigger that you install yourself. Also, regarding a gunsmith, if you only plan or firing the rifle a few times a year (100 rounds) then go for it, But here at the site we promote every owner to know his rifle inside and out, and to be able to repair the parts as they wear out. For most of use, it is not uncommon for use to shoot 10,000-40,000 rounds in a year. Here are the owner’s manual and the repair manual you can get a feel for the rifle. [url]http://www.ar15.com/content/books/TM9-1005-319-10.pdf[/url] [url]http://www.ar15.com/content/books/TM9-1005-319-23.pdf[/url] |
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Okay, the gun had the R6600 HBAR buffer and a A-2 length spring and stock with a car upper. I guess what could have been happening was that there was too much weight in the buffer for proper feeding as there is no contact between the hammer and bolt carrier when you ride it forward and the gas system seems clean otherwise. I am adding an M-4 type 6 position from Bushmaster with (I assume they'll send) the car or M4 spring and buffer, so that should fix it. Why is the car buffer different from the M4 buffer? Aren't the (civillian) barrels the same length? Shouldn't barrel length be determinative as to the amount of gas and, I assume, weight of the buffer? Also are the car and M4 springs the same? Thanks for your help and thanks in advance for any answers as to the car vs. m4 buffer spring question. |
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[B]Quoted: Okay, the gun had the R6600 HBAR buffer and an A-2 length spring and stock with a car upper.[/B] It's the correct buffer and spring for the long A-2 stock. [B] I guess what could have been happening was that there was too much weight in the buffer for proper feeding as there is no contact between the hammer and bolt carrier when you ride it forward and the gas system seems clean otherwise. [/B] I don't buy this. I would say that either you still have some sort binding, or the gas passage may have some fouling that you haven't removed. [B]I am adding an M-4 type 6 position from Bushmaster with (I assume they'll send) the car or M4 spring and buffer, so that should fix it. Why is the car buffer different from the M4 buffer? Aren't the (civilian) barrels the same length? Shouldn't barrel length be determinative as to the amount of gas and, I assume, weight of the buffer? Also are the car and M4 springs the same?[/B] The standard buffer is lighter than the H buffer. The H buffer is an upgrade that slows the carrier cycle down at bolt unlock and slows down the rate of fire due to the heaver weight. The gas port that is drilled into the barrel is what determines the amount of pressure that will be sent to the carrier, not the buffer. The port size is directly related to the amount of barrel after the gas port. If you have the correct buffer and spring in the current rifle, then I have on more suggestion. I still believe that the carrier is slightly binding (could just be dry) and your gas system may be slightly clogged. These two combined could be casing the problem. Get a can of BreakfreeCLP and give the rifle a good cleaning. Remember to spray the CLP down the gas tube to allow it to dissolving any baked on fouling that may have built up in the sight tower gas passage area. Also, allow the CLP to sit a while before you wipe it off. Since the rifle was stored for a while, any fouling that may have been missed could have dried out and be causing the problem. When you’re done cleaning, make sure that you only lube the rifle with the BreakfreeCLP, and no other oils. The carrier (spray down the key), the bolt (all the surfaces), and the buffer and spring should all have a light coat of CLP on them before they are reinstalled. |
| On your feed problem, what are you shooting for ammo? I have had feed problems with surplus ammo that has tarnished brass in my Bushmaster. Never had a problem with my reloads of this brass when I run it through the tumbler. But most likely a good cleaning will help out. |
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It's possible that your Mag Release needs to be adjusted to hold the mag higher in the Mag Well so the rounds get engaged by the bolt and are driven into the chamber. I had a similar problem and this worked for me. I do know for a fact that this adjustment is legitimate, I just can't point you to the source. I forgot how to adjust this, but I'm sure someone else knows. |
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There are two tweaks to fix feeding problems if you have a problem with the mag or catch. The first is to tighten the mag catch. Pushing the mag catch button all the way, then reaching over and tightening/rotating the catch lever one more turn clockwise, will tighten the catch. It does not make the mag higher in the well; it makes the catch hold the mag tighter and keeps if from drooping and wiggling (front to back). The second is to the mag spring it's self. As a mag spring weakens, it applies more pressure to the front of the follower, than the rear. This causes the rear of the round to not return all the way back up to the feed lips, when the carrier moves over the rounds on the cocking cycle. As the bolt returns on the forward stroke, the back of the round is lower/out of position and the bolt will either pass over the round, or jam the round, due to being held out of the correct position. The tweak is a controlled bend to the spring at the first wind to even out the spring force that is applied to the follower. This makes sure that the round is fully return to the entire feed lip surface, and not just the front with the rear dropping down. |
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