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Morini CM84 Sight Adjustments?

Posted: Thu Jul 01, 2010 6:16 pm
by Gwhite
Both the manual I have and the one on-line at Mornini only tell you which way to turn the screws. There is no info on how far one click moves the point of impact, or whether the elevation & windage are the same. I did a search, and came up empty.

In addition, it seems like I have to make a significant windage correction when I adjust the sight width. I would have though they would have set the screw up to move each half symmetrically, but maybe not. Either that, or mine is sticking on one side.

Any thoughts or info?

Thanks!

Posted: Wed Jul 07, 2010 10:32 am
by Mark Briggs
I don't recall what distance the point of impact is moved with each click of adjustments - one of the shortfalls of being an instinctive sight twiddler who goes by the "that looks about right" rule.

To give you an idea of order of magnitude for sight clicks... If the group is centered just to the left of the 10-ring, between 9.5 & 9.9, I would take two clicks to the right and expect x-ring grouping. That works out to about 3-to-4 clicks per whole scoring ring. If your group is centered in the 8-ring then take 7 or 8 clicks to get it to the x-ring.

As for making windage adjustments after adjusting rear sight notch width, this normally should not be necessary unless you are at or near the limits of travel on the adjustments. I'd suggest you take a few minutes to follow this procedure...
1) adjust windage fully left
2) counting clicks, adjust windage fully right
3) adjust windage left by 1/2 of total click count (this should roughly center the rear sight)
4) if you have a vernier caliper, measure the amount by which the rear sight halves project out past the edge of the rear sight base - this should be very close to being equal if the rear sight is centered
5) adjust rear sight notch width to maximum
6) measure the amount by which the rear sight halves project out past the edge of the rear sight base - if the width adjustment is working as it should the two sight halves should project an almost equal amount past the edge of the rear sight base

If the above test fails, do a search on the archives here. One of our distinguished contributors (Steve I believe) published a note here on how to get the rear sight width back in "sync" - this was probably 3-4 years ago.

Hope this helps.

Posted: Wed Jul 07, 2010 10:36 am
by Mark Briggs
It appears the esteemed David L has quoted Steves Morini sight "how to" article in a thread below. I've pasted it here for handy reference.

O.K., I had to go through soem fine tuning on my new 162E. I have a 6mm front blade (barn door) and use about 1/3 the front width on either side (open barn doors) on a sub six hold (front sight on bottom edge of barn doors).

Bad eyes.

Anyhow, I first noticed that it appeared as though I could have either wide notch, or centered notch, but not both. I Feel Your Pain.

If you aren't comfortable chasing little springy bits around your house, stop now and send to Scott.

Assuming you are prepared to completely disassemble your rear sight assembly, do so now. When you get to the point where the rear notch sub assembly is "free," you will note that (oh by the way, put that spring that just went flying across the room in a Safe Place. And yeah, hope you got a real good look at exactly how it is supposed to go back in cause it's real easy to do it wrong) the two halves of the blade can be rotated along the two-threaded rod piece they are attached to. The rod is counter threaded (IIRC) so screwing them in the same direction actually moves them in tandem along the rod left-right; screwing them in opposite directions makes them either closer together or farther apart.

Hope you counted the number of clicks used when disassembling the rear sight assembly . . . this comes in real handy later so you can tell whether or not you actually amde things better before reassembling the whole danged thing to find out you actually just made it worse! As you unscrew the rear blade subassembly using the L/R adjustment screw you are creeping the two blade halves along the double-threaded rod at the same time. This gets clearer here in a paragraph or two.

Once the rear blade subassembly is free, take a moment and admire the elegance of this engineering solution. No, seriously! Cussing out the design engineers right now isn't helping. It is a quite clever piece at that.

O.K., what you are trying to do is get the blades wide apart, but way over on the left side of the rod. When you screw the rod-blades subassembly back in, you want there to be enough threads left to get the RH blade over to the RH side without running out of thread.

This is really hard to explain without your actually seeing it.

You will have to flop the left blade >>out<< (notch wider!) a few revolutions (how many is a few? wish I knew. I didn't follow the advice I'm giving you right now; I had to Find Out The Hard Way). ANyhow, I think two or three revolutions should do it . . . oops, the left blade just popped off the rod! O.K., one less than that then. Stiff upper lip now; back at it!

Anyhow, be prepared to fiddle with this several times installing/tweaking/re-installing before you get it just right.

Re: Morini CM84 Sight Adjustments?

Posted: Sun Jul 11, 2010 8:35 am
by imbecile
Gwhite wrote:Both the manual I have and the one on-line at Mornini only tell you which way to turn the screws. There is no info on how far one click moves the point of impact, or whether the elevation & windage are the same. I did a search, and came up empty.

In addition, it seems like I have to make a significant windage correction when I adjust the sight width. I would have though they would have set the screw up to move each half symmetrically, but maybe not. Either that, or mine is sticking on one side.

Any thoughts or info?

Thanks!

Maybe this can help. http://www.targettalk.org/viewtopic.php ... +ajustment
Just read first post.

Posted: Sun Jul 11, 2010 8:58 am
by Gwhite
Thanks! I did a search before I posted, and didn't find this one. That has the key piece I was missing. Coincidentally, I also have a 162, so now I'm set with that as well.

It's interesting that the elevation & windage adjustments on the CM84 differ by about a factor of one and a half.