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Posted: 12/22/2012 11:09:26 AM EDT
| I think just received an out of spec upper receiver. When I put it on two different stripped lowers with no take down pins it fits perfectly. However, when I install the front take down pin, it doesn't readily close to allow installation of the rear take down pin. In fact, I have to squeeze the two halves together to get them to close. It appears to be binding on the areas where the receivers meet up by the front take down pin. Without the pins, the holes for pins in both receivers line up perfectly on both lowers. Do you think I'm right that the problem is the upper? Maybe the machining is off a few thousandths? |
| Seen a lower receiver that the front pivot hole was a little low and caused you to have to force the upper down. Uppers would spring back up when you let go of them at the back when attached to the lower. Guess a misplaced pivot hole could happen to an upper as easy as a lower. |
| On two differen assemblies I have experienced the "fit" issue. One was a matter of too much material at the front of the lower receiver just behind the hinge pin...... a few seconds in my milling machine and the fit was perfect. The second was an issue at the rear of the upper A2 receiver, The radius was just enough different the lower pin was off by about .080". I fit the upper to several other lowers to make sure what the issue was. I then changed the radius gradually with much Dykem blue till I had a perfect fit. Both rifles functioned perfectly after the fitting. In normal times a call to the dealer would get your issue taken care of but now I am sure even if the dealer takes care of the issue there will be a long wait... Larry |
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