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Old 07-01-2019, 10:18 AM
roddy

Join Date: 
Nov 2017
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Well guys, it's back together and functioning as it should. While doing the strip/clean/test-fire routine, I found a couple of things worth noting...

Misfeeds/FTL, and accuracy issues seem to be the most common complaints I found while searching out info on this rifle. If you have these issues with yours, I may have found solutions...

FTL: First, make sure it is clean. My first test fire session (before cleaning) showed it was pretty much a single-shot semi-auto. Even then, it was a pain to get it to pick up a round. After cleaning, it would fire the first 2, then either fail to load, or jam up on the next 3.
While thinking about a way to add more tension to the magazine spring, I noticed a rather large amount of clearance between the feed lips on the magazine and the grooves in the bottom of the bolt. If the round wasn't sitting perfectly, there wasn't enough brass there for the bolt to pick up.
I tweaked the feed lips up and out a bit, then test fit, and still found more than enough clearance. This allows the round to sit about 1/16" higher, and better centered in the magazine. The protrusion in the bottom of the bolt now picks up a round every time, and I have no more feeding issues. Nice.

Accuracy: After getting it functional, I decided to try sighting it in. That was a head scratcher. The first 3 rounds were pretty much 1 hole (only 25 yards), then one to the left, and one to the right. The next bunch were all over the place, but occasionally 2 or 3 would hit right on top of each other. I noticed that although it was all over the place windage-wise, it was pretty good on the elevation side of things.
This led me to the front sight. I tapped the hood off, and the front sight fell out in my hand! The dovetail is too loose, and the sight isn't wide enough to be locked in by the hood. This means the sight is sliding left and right by almost 1/8" while the gun is being handled. Wow!
I took a hammer and chisel, and gave the leading edge of the dovetail on the sight a wack, then tapped it back into place. It doesn't move now. I haven't been back out for another test session, but I'm pretty sure I found the issue.

I'm not saying this will be a cure for everyone, but if your 490 suffers the more common issues I have read about, this is a good place to start looking. If it makes any difference (for comparison sake), my rifle is in about the first 1/3 of production (ser # in the 9000 range).
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Last edited by roddy; 07-01-2019 at 01:18 PM.
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