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Adjustable iris? ... VOSTOK CM-2 & Ural Rear Sight Apertures Compared

4K views 17 replies 6 participants last post by  Charlotte 
#1 · (Edited by Moderator)
Adjustable iris?

The adjustable iris rear aperture must be a newer type sight than the ones on my "Vostok" Ural, and CM-2. As they are marked for the various size diameters, and aren't adjustable like the one ewald got on his Ural, you have to have the different rear peep apertures in the various sizes. Anybody out there have one they'd like to sell/trade? Just an observation I made after looking at ewald's excellent pics.
Michael
 
#2 ·
... Just an observation I made after looking at ewald's excellent pics.
This is why the photos are so important.

Ladies and Gentlemen,

If you post any images ... please maintain the photo link.

So future readers, forum browsers and Russian Rimfire aficionados can continue to enjoy the thread/post to the fullest.
 
#3 ·
I sure do agree about the photos. Is there any way the photos could be stored on the RimfireCentral server so that we wouldn't have to worry about keeping links operable? In the past I've had photo host sites crash and loose photos on me. Some hosts are more dependable than others, the one I have had the most trouble with is Hunt101. Photobucket has been pretty good so far.
 
#4 ·
The adjustable iris rear aperture must be a newer type sight than the ones on my "Vostok" Ural, and CM-2. As they are marked for the various size diameters, and aren't adjustable like the one ewald got on his Ural, you have to have the different rear peep apertures in the various sizes. Anybody out there have one they'd like to sell/trade? Just an observation I made after looking at ewald's excellent pics. Michael
You may want to talk to Mac Tilman at MT Guns and see if he has any spare eyepieces for the new CM-2 rifles. They will fit the older CM-2 sights.... at least mine do. However, the front sight inserts will not interchange.
 
#5 ·
I spoke with Mac sometime back, gave him my measurements, as he said there were two different shank sizes, and it wasn't real clear at the time which one I needed. Anyway you might provide the ID on the rear sight hole, or the OD of the aperture shank? I believe you have a "Vostok" CM-2 very similar, if not identical to mine. Both my Ural, and CM-2 have the same dimensions in those aspects. Thanks.
Michael
 
#7 ·
WH, look on your rear aperture, and see what size it is. Mine are 1.2mm, and 1.4mm. I'd like to have a 1.0mm, actually I'd like to have ALL the different sizes, but I figure it'd be cheaper on me to just get the adjustable iris. I agree with you on the excellent sight picture, just the way it is, but it'd be nice to have all the different adjustments all in one piece.
Michael
 
#8 · (Edited)
Okay. Left side says:
UEHA (the U is actually a "mu" in Greek. E = Epsilon) 1 WEAYKR
HA 50M-2.5MM

The elevation numbers go from 0 at the top to 20 at the bottom.

The rear aperture (just a hole not adjustable) is just slightly larger in diameter than the ball on the end of a ball point pen (BIC). Smaller than the cap of a steel pin cap. I can't see any numbers inscribed on the hooded aperture hole sight at all.
Just discovered M-1100 is also stamped on the cocking sear of the bolt! as well as the upper side of the arm and also the side of the bolt face. Talk about serial numbers ALL over! Even the stock has the serial number at foreend closest to muzzle. Buttplate has M1100 in the aluminum. I can't believe these guys stamped every part with the serial # can you imagine how much work that must entail?

I just ran a borescope through the bore and every land and groove has "M-1100" finely etched on the surface just ahead of the chamber in the throat....just kidding! I have no bore scope so I cannot verify this.
 
#12 · (Edited)
I don't know if larger or smaller would be better but I put my eyeball almost into the hood and all I see is the front circle sight and anything in the middle of it! It seems easy to center something as small as a peanut shell at 50 yards with it. There is an inherent optical precision in centering something in the exact middle of that circle.
 
#14 ·
Peep Sight Principle

... It seems easy to center something as small as a peanut shell at 50 yards with it.
There is an inherent optical precision in centering something in the exact middle of that circle.
It is all about light. The human eye seeks light.

Peep (aperture) sights work because the eye has a natural tendency
to center itself when peering through a hole - looking for the most light.

When one peers through a hole such as a peep hole.
The eye in-order to see well, unconsciously, looks for the most light.
Generally, at the center of the hole - the center of the rear aperture.

Moreover, the object that is being viewed (front sight).
Also, unconsciously, becomes centered in the line of sight.
And, in the center of the rear aperture where the most light is detected.

If the front sight happens to be an aperture (peep hole)
rather than a post with bead.

The eye, once again, is unconsciously centering itself
to see through the front aperture.

If the target is a series of concentric circles.
The process repeats itself.
The eye, unconsciously, attempts to center ...
the center of the circles ...
within the centers of the apertures.

Beginning shooters attempt to help the process along.
By, consciously trying the center the front sight
in the rear aperture.

And, then, consciously trying to center the target
in the center of the front aperture.

The wrong thing to do ... fighting nature ... fighting himself.
 
#17 ·
No way Jose am I going to put a scope on my Ural. When it arrived it had ONE front insert--the circle--and I spent about 2 hours just sighting offhand at little small rocks and things from 10 to 60 yards, along with sighting in on objects at 100 yards. What I like especially is the fact that if my target is beyond the zero I CAN SEE the target as I compensate for bullet drop--no post to block out the target.
 
#18 ·
Not trying to be contentious, but in the anal retentive sport of smallbore prone you'd better monitor the centering of the entire front globe in your rear iris. Your head position can be off and give you an inaccurate sight picture.
I'll have to give Anschutz a little praise on the shape of their cheek piece regarding this issue. At first I didn't like the angular shape of the cheekpiece on my 1907, but have noticed that it is easier to have a repeatable head position and eye alignment with the rear iris. In the off season I plan on altering the shape of my CM-2 cheek piece to give me more of a shelf for my cheek bone to rest on.
 
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