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Posted: 10/17/2005 11:32:23 AM EDT
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Okie dokie-- So I've now built my first ever AK that doesn't feed right. Here's what I know and any thoughts, suggestions, possible causes, would be appreciated. So this beast would appear to be just fine, that is when you look at it, or even on hand cycling. The carrier is nice and smooth on the rails etc. However there are two distinct issues that seemed to show up during test firing. The first is more or less trivial and may be related to the second. #1 It does not seem to group very well... at 25 and 50 yards it seems that every fourth shot or so tends to be a flier placing as much as 8" from the rest of the shots. #2 This thing stove pipes like mad. The fired round will get hung up somehow and not eject, turning sideways or in some cases being caught long ways... The carrier will begin to pick up the new round from the mag and in the end you end up with a paritally fed round smashed into the breech and a spent casing wedged right along with it. Not sure if #1 has to do with #2 or not, but the ejection and feed problem is the most serious. It leads me to believe that when firing the bolt carrier doesn't always go all he way to the rear. Could this have to do with the SA-85 having both vents at the back of the gas block and a vented gas tube? |
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I have a couple rifles with both the vented gas tube and vented gas block, they function flawlessly. I just built a gun (Romy) where the front trunion seats too high in the receiver, it's a very odd thing and I have never encountered it on another build. It took me a while to even find that it was doing it. I never shot it but it would jam the nose of the bullet into the chamber face which I was sure would cause an issue. Check the distance from the top of the receiver to the locking lug with a known good functioning rifle. Mine was about a half a mm taller on the right side. So far I have disassembled it (rivets are fun to remove on a receiver you plan on saving from scratches /gouges.) I also filed the receiver and trunion to allow for a 'deeper' seat. Tonite I will start setting rivets and see if I can keep it where I want it. Good luck. |
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For what it's worth, it does function flawlessly sometimes. At times jamming every 6 rounds or so at others every 2... I went through at least one mag of 30 with no failure to feed... It's weird. The round smashing into the breech only occurs when the spent casing fails to eject. |
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OK so I think I solved it. I believe that the extractor wasn't moving well and was failing to completely grab the casing so that it followed the bolt carrier and passed the ejector. No positive and haven't shot it again yet, but I was getting the feed problems to occur just hand cycling and now they aren't. We'll see. I also took a file and sandpaper to the trunnion to make sure there were no burrs or weird things getting in the way of the lugs locking into place. |
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