Front sight base pins do not align.
Hello seasoned builders. This is my first in over a decade and I have forgotten more than I know. It's a typical AR set up in rifle form... nothing clever. I bought a new barrel DPMS and a reasonable looking front sight base (don't recall brand). Both were drilled so I thought they would line up. Front to back they are fine but the up/down match is offset by a significant amount. I can see light under the bottom of the barrel when I look through the base. I can see a good portion of the barrel's holes but if I put the taper pin in the hole, it hits the bottom of the barrel pretty solidly. Did I goof and buy a bad match? Are these supposed to be interchangable, therefore drilled to standard settings? Any help is appreciated. Thanks.
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Is the offset visible when looking from both sides of the sight base/gas block? You might need to simply rotate the sight base a bit to get things to line up.
Edit;
It looks like you get to go shopping for a new sight base!
What brand is the one that isn't lining up?0 -
Yes, the offset is the same on both sides. It appears the holes on the base are too low. I also lined up the base parallel with the receiver to double check and it was the same as mentioned before. The seller of the base said different base manufacturers have their jigs set up differently and it's best to match barrel maker to base maker. True? Thanks for the reply. 0 -
I've run into a bunch of folks, selling AR parts and accessories recently. Appears they and the stuff they are selling, are out of China? When you backwards engineer something, from our system of measurement,to metric dimensions. Wouldn't be surprising if something wasn't a little off, from tolerance stacking or soy sauce on the prints. 0 -
quote:Originally posted by NeoBlackdog
Is the offset visible when looking from both sides of the sight base/gas block? You might need to simply rotate the sight base a bit to get things to line up.
Edit;
It looks like you get to go shopping for a new sight base!
What brand is the one that isn't lining up?
Supposedly Delton?0 -
I attempted to remove & re-install a pinned FSB once using new pins. I discovered I didn't have the nerve to beat on the pins hard enough to get the new pins driven home. Ended up putting the old pins back with thread locker and hoped it held.
Moral of the story: I didn't remove any more pinned FSB with the intention of re-using them.
I will say you shouldn't be able to see light between barrel shoulder and FSB so one or the other is out of spec. Measure and see which.0
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