Thread: Kahles
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Old 19th August 2013, 11:39 AM
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RobF RobF is offline
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Originally Posted by maestro View Post
There's not a real need for them in FT, 1/8 MOA @ 50 m covers 1.82 mm so with 1/4 MOA clicks the maximum difference between theoretical and dialled elevation is 1.82 mm while with 1/8 MOA clicks it is 0.91 mm, I don't think that this would count so much. Please consider that even 1 metre misranging causes already 3.5 mm POI-shift...

I don't think so, just have a look at the S&B scopes, the size of one click is physically limited (about 2/3 of a mm), the FT version with 1/4 clicks has 32 MOA in one turn while PM-II with 1/8 click has only 16 MOA.
1/4 MOA covers about 1 yd of dialing from 50-55... most of my rigs have this even from 40 yds on... about 5 1/4 clicks, perhaps going to 6 between 50-55. So you have a click for every yard yes. However I prefer 1/8th so I can dial in 52.5, not 52 or 53. And they are just clicks. The amount the turret turns by is defined by the thread. I've got 10 MOA on my march and it's not that tight, and the turret is about 1/2 the width of the Kahles.

You'd be only dialing out of 16 MOA for say an 8 or 8yd target. These are quite rare targets these days.

Having used both, I just prefer 1/8ths over 1/4's.

1 MOA is 13.3mm at 50yds
1/8th is 1.6mm at 50yds
1/4 is 3.2mm at 50yds about the same a being a yard out... that's why i have 5 between 45-50...

A 50yd 40mm target means you have 35.5mm to put a pellet into unless you want to split. So if you want to be level you have 17.25mm of error before without clipping an edge. Given that most are shooting above say 12.5mm groups edge to edge, it means you have 11.25 mm of error left allowed to your group size for rangefinding errors, or less that 4 1/4 clicks. Why not just allow yourself to be as exact as possible? You can only have this room if you have the wind spot on. If you get the range wrong by a 1/4 click or more, then your wind reading needs to be perfect.

The wind issue has a big impact on your chances. 1 1/4 MOA, your chances are about 95% with the wind. 2 about 85%, 3 about 60%, 4 about 45%. And thats if you are perfect with the wind.You have to visualise the likely group and not an individual shot.

With 1/8th MOA, that doesn't change except you can be in between 60% and 45%...

Of course these estimates change depending on how tight a group you can shoot, and how well you can rangefind. If you can do better, you can get better % chances of hitting, and it makes less difference until you are way above or below the centre. It's why group sizes are important even though we shoot 40mm targets. And why wind reading is so important.

But I think most people aren't within one yard, and aren't shooting less than 12.5mm CTC groups at 50 yds, so for them it just helps, and doesn't do any harm (except if they can't count turns or read the sign that says you are a turn out )
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