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Posted: 5/21/2012 5:35:59 PM EDT
| So here's the deal: last year picked up a slightly used Bushmaster XM15. Very slightly used, roughly 200 rounds through it. Has a fixed carry handle, and wanted to convert it to a flattop, so i snagged a 16" middy from PSA. Pinned the upper on and everything looks flawless. lines match up perfectly, overall, very impressed with PSA's work. Put in my BCG, and CH, check function: buttery smooth. No hitches. Go to insert a mag... and it takes what I would call a love "punch" more than a love tap. When i engage the mag release, it's slightly resistant to press, then, for lack of a better term, chops in and drops the mag. So in other words, not a smooth release. even with the BCG out it does this. is this normal with brand new uppers sometimes, cause they have fresh coatings and aren't broken in yet and loosened up? This is the first NEW upper I've had. Even took a mini tape to the upper and measured out to the millimeter, as far as chamber widths and whatnot. All match up with the Bushmaster upper. Just something that will correct a bit over use, or is it just that Bushmaster's specs are more commercial oriented, as opposed to PSA's mil-spec dimensions? Thanks a bunch for the input!! |
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Two items to play check out.
Starting with new upper on the old lower, look straight up into the front of mag well openning. Confirm that the upper receiver front of mag well surface is flush with the lower mag well surface. If the upper receiver mag well is protruding past the front wall of the lower mag wall, this will cause mag seating problems. Next, take the back end of the pencil, push the mag release button in as far/deep as it will go, then reach over and spin the mag catch off the lower. Go ahead and remove the mag release button and spring behind it as well. Now clean the mag release channel and parts, and before you go to re-install the mag catch, make sure to lube the parts and the channel with CLP. Note, when you reinstall the mag catch, flush the threaded section of the catch out with the face of the release button. If you find that the threaded section will not flush out (1/2 thread either way). pull the catch again, and turn the release button 180 in the lower receiver channel for it. |
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Quoted:
Two items to play check out. Starting with new upper on the old lower, look straight up into the front of mag well openning. Confirm that the upper receiver front of mag well surface is flush with the lower mag well surface. If the upper receiver mag well is protruding past the front wall of the lower mag wall, this will cause mag seating problems. - Just triple checked. Not the issue. Both surfaces are flush. Next, take the back end of the pencil, push the mag release button in as far/deep as it will go, then reach over and spin the mag catch off the lower. Go ahead and remove the mag release button and spring behind it as well. Now clean the mag release channel and parts, and before you go to re-install the mag catch, make sure to lube the parts and the channel with CLP. Note, when you reinstall the mag catch, flush the threaded section of the catch out with the face of the release button. If you find that the threaded section will not flush out (1/2 thread either way). pull the catch again, and turn the release button 180 in the lower receiver channel for it. guess this is an adjustment for the mag catch, for if it's gripping and inserted mag too tight? the channel and parts are clean and free of residue. What I'm confused about is how a mag inserts and seats totally fine with the Bushy upper on, but does this with the new one.  I appreciate the reply! Both were very good suggestions which I didn't check before. |
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