Looked up the MVP Scout and found this picture.
That does indeed look like the rear sight I have, and the post does look threaded when I peer at it from the bottom of the detached rail, and it’s easy to see that the side set screws have been turned in far enough to damage the threads; but the ring does not twist around the vertical axis
at all, and I’ve torqued on it hard enough to be scared of shearing it off.
Now, I haven’t tried the penetrating oil, because it doesn’t look corroded; but I’ll do that.
Yup, that was it. I squirted it with WD-40, then loosened the set screws, put an appropriately-sized steel punch through the ring, and torqued it back and forth. After about three swings with no movement, it broke free and started turning under protest.
Maybe it
was Loctite Red. Weird, though: it's a brand-new rifle, straight from Mossberg.
In other news, in case you're interested, I like it a lot except for a few things.
First, it doesn't have a third sling stud. I understand that Ching slings are expensive and Mossberg doesn't want to include one for free, but a Scout rifle without a third sling stud doesn't make sense.
Second, it's got a bull barrel. Haven't figured out why. Scout rifles are supposed to be light. This one's under seven pounds, barely, but it seems they could probably turn another half pound off the barrel.
Third, it comes with short rails bolted to the left and right of the stock up front. Lasers and flashlights and whatnot, I imagine. But a Scout rifle should not be contaminated with heavy, bulky extra crap: it's supposed to be light and handy.
Fourth, and this is a small one, I wish it had a three-position safety. Two is okay-I-guess, but I do like to be able to lock the bolt down. On the plus side, the safety is precisely where it should be for a right-handed shooter.
But there are plenty of things I like about it too. Short, handy, perfect cheek weld when thrown to the shoulder, trigger and bolt throw about as good as can reasonably be expected on a commercial-grade rifle. I put a nice Leupold FX-11 Scout (2.5x, 28mm) with low quick-release rings on it, and it's very nice too.
Anyway, it turns out that the WD-40 was indeed the special sauce. Thanks, Jim in Idaho, Hotrod_Lincoln, and Dave_in_WV.
