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Posted: 6/3/2004 10:11:18 AM EDT
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OK I have an older upper and Im using a new carrier with poor finish on it. The thing is when I insert the carrier it gets pritty tight after about a 1/4 way. I can push it in and it loosens up after about an inch but its still tight. Comming out is the same way. Ok is there a break in for new bolts or is it out of spec? Thanks |
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Likely the upper is bent in a little, the sides pinched in. This happens if you rebarrel using an action block and forget to put in the insert or a bolt carrier while rebarreling. Or it just got banged sometime. It is aluminum, it is soft, can bend. It happens. It does not take much to make it bind, and it is easy to fix. Put the upper half up in a vise, held by the carry handle. Support the end of the barrel with something, a paint can, whatever, to hold it up horizontally. Pad the carry handle in the vise so it does not mar. I use some strips of rubber cut from the tops of old rubber boots. Leather strips from an old belt will work, too. Do not clamp it such that it will damage the rear sight. Now, gently slide the bolt carrier in and find where it begins to bind. If you look, sometimes you can see the sides flex out a little. This is usually at the rear of the ejection port, which is where it is weakest and most likely to be bent in. Do this with no oil on the carrier or inside the receiver. You don't want to mask the problem with lubricant. You need to feel exactly where it is binding. Use a couple of combination wrenches, large ones, say 15/16 and 1", not critical. Wrap the open ends with some electrical tape (so they don't mar the aluminum), an stick those ends down in the charging handle channel. Note where, when you pry, the wrenches will touch the sides of the receiver, and wrap some tape on the wrench there too. Now insert the two wrenches and GENTLY pry the sides of the receiver open. One wrench should bear right at that tight spot even with the rear of the ejection port. Remove the wrenches and try the bolt carrier again. Repeat until it slides smoothly. Do this with NO oil. When it is all freed up, lube and reassemble. |
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