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Old 21st November 2009, 10:11 PM
Weevie Weevie is offline
Join Date: Apr 2009
Location: Worcester
Posts: 254

Originally Posted by Sam Vimes View Post
I'm with Dave on this one although I've long suspected that we are in the minority. Far too many folks rush headlong into mounting scopes as low as possible without really thinking about what they are doing. On a rifle without an adjustable cheek piece I can almost understand it, on a PT I can't. Leave the standard rail on the rifle and accept that you won't get the scope quite as low as many would wish. If you really want to mount a scope lower on a PT then look to low mounts and a scope with a 1" tube.
I think the reasoning behind this low mounting for HFT is that for longer shots you get the luxury of a 35-45mm KZ; many longer shots (although the Gathering at Emley gave the lie to this ) are 40mm.

15mm KZ targets can be between 13 and 25 yards. When your scope is mounted relatively high this gives quite a wide range of aimpoints, add wind into that and it can be quite awkward.

With the BKL lows that you kindly sorted for me my scope is about 1.86" high. I'd not want to go much higher than that for HFT.

With my scope setup and my pellet velocity and notional BC I get the following aimpoints from Chairgun Mobile (I'm posting from my Linux setup so I haven't got access to Chairgun 2 and so it may not be quite right but you get the idea)

13 -0.36
14 -0.16
15 0
16 0.12

So between 13 and 16 yards that's 5mm odd difference, which leaves you 2.5mm from the top of kill. With a bit of an updraft that could mean the difference between a kill and a splitter that leads to a plate.



I've just done a comparison with a 1.5" scope height (which IIRC and I may not, is about what it was with medium mounts and an S400) and the aimpoints between 13 and 16 are obviously different from a 1.86" scope height (they're a bit higher)...

...but the gap between 13 and 16 for a 1.5" scope height is about the same as with the 1.86" scope height.

I've left the post as I originally typed it to show that it's easy to accept received wisdom that turns out to be completely wrong!

So in conclusion then, Chris and Dave are absolutely correct. Get some lowish mounts and leave the scope rail where it is.
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