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Posted: 12/24/2006 2:59:34 PM EDT
| My new DPMS upper on a new DPMS lower has that slight upper to lower wobble thing, wherein the upper moves left to right a bit. I realize this does not impact accuracy, since the sights are on the upper, which moves as a single unit. I also realize this does not impact functioning, etc. This does upset my sensibilities, however. I puttered with an Accu-Wedge, having to continue to whittle off bits of the circular portion of the A-W until none was left to get the upper down low enough on the lower to slide the rear pin into place, reducing the A-W to a sliver of red plastic. What is the solution to this? I am going to swap out lowers and uppers, BUT I just finished a J-P trigger job, etc, and don't want to change to a non-JP worked lower. It's almost as if the front pin is undersize, causing this to happen. I know this is a common topic, so apologize if this necessitates a redundant string of responses. On a positive note, I just found my gift package to Paktika, Afghanistan arrived yesterday to everyone's delight. |
If the wobble bothers you that bad, here is what i would do, try not to laugh, it will work. Use brake cleaner/degreaser on the top edge of the lower or bottom edge of upper, either will work. Now apply a small bead of Ultra Black silicone (hardware or auto store) all the way around edge. Lay a piece of cling type plastic wrap between the upper and lower and close 'em up. Leave them to dry overnight. When dry open up, remove wrap, and trim excess off with razor or sharp knife. Poof, no more wobble, and you will barely notice the black silicone between the upper and lower. Just an idea.
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Did I miss a memo???? Last time I checked, the DPMS receivers where still low shelf units, hence the Accuwedge should not have been cut. Granted that it will take a bit of downward pressure to compress the wedge the first few times, I would say that you may need to order a new wedge for the unit that you destroyed by cutting. Also, if the wedge is too stiff to begin with, soak it in CLP for a day or two. |
I disagree with that statement. When you fire the shot, the recoil will cause the upper to shift. Its as if you weren't holding the rifle at all for a split second. The wobble introduces one more variable that you haven't controlled yet. To make things clearer: would you install a door hinge between your buttstock and your lower? Even folding stocks (at least, the good ones) have a locking button to prevent wobble. It's worthwhile doing EVERYthing you can do to eliminate variables when shooting. |
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Thank you for the comment regarding the wobble effecting accuracy. My intent was to suggest that at 62 ,with bad eyes, two fractured vertebra in my neck, a disrupted scapula, the least of my problems is a .003 wobble in upper to lower...;-) To reply to another comment-The A-W had to be cut repeatedly and I finally gave up, hence my post. The A-W required more force to close the upper to lower than I could apply by leaning on the unit with all my weight on a pad on my bench. I will try soaking one in CLP and hope for the best-I have about ten of them, which I picked up from DPMS at a show, very cheaply. The silicone has the beauty of simplicity, I will give it a try. You learn more here by accident than elsewhere by design. |
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