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Scope magnification/objective size considerations.

1172 Views 1 Reply 2 Participants Last post by  cajungeo
What is the reasonable maximum magnification of the scope for Mini-14?

Even highly-accurized Mini is not likely to be used beyong 300 yards and ffield of view is crucial for survival in a tactical weapon.

Would it be accurate to suggest that 4x magnification is the reasonable limit for a tactical Mini? Even dedicated regular sniper weapons (7.62/.308 - not .50 cal) use 10x fixed-mag scope and they are used at 600-900 yards and do not care about field of view.

Would it be accurate to suggest that fixed-magnification is preferable for a tactical weapon for plenty of reasons like simpler, more reliable construction, better waterproofing, getting used to the same sight picture and no chance to forget it at different maginification, etc.

If we assume 4x is the limit, in complete darkness fully adjusted human eye pupil is about 7 millimeters.
7x4 = 28mm - that makes 28-32 millimiter objective lens the highest practical size for a scope objective with 4x magnification. Anything higher than that results in wider exit pupil than the eye's pipil size and wastes light.

Considering that the more reasonable pupil size is 5 mm or less, even in darkness, especially for older people who's eyes do not adjust that well, 5x4 = 20mm should be plenty for Mini.

A scope with smaller objective is less bulky, can be installed closer to the barrel helping with aiming and reducing parallax, is cheaper - or better quality for the same price, introduces optical less distortion - since it uses only the center of the same lense, more robust, less likely to shift under recoil due to lower mass, etc.

So, would it make any sense for me to buy anything other than 4x20 scope with widest field of view for my Mini? And 10/22?

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I put a 3-9x40mm scope on my mini. I leave it on 4x most of the time. The larger objective has a larger field of view, better for fast moving animals. Turning it up to 9x the field of view is greatly reduced, and also light transmission is reduced. Its best to compare, and try before ya buy. Take in a large gun show. The coatings, and lens quality will also make a big difference.

I have a 6-24x44mm target scope on my 10/22. I am finishing up building for target use. That size scope would seem a bit overkill, but in using it for target use I can see the bullets hit the target at 50 yds.

The big difference using a scope on a rim fire is the parallax on a rifle scope is usually factory set at 100 yds. So on a rimfire it is recommended to get a "Rimfire" scope where parallax is set at 50 yds. or get one with and adjustable AO. Mine is adjustable from 25 yd to infinity. I am also building another 10/22 for hunting, I will get a 2-5x28mm rimfire scope for it.
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