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Following some excellent tips and advice from Gaz M, I've been doing some dry-firing practice at home - Initially I just put a small dot on a piece of card to line up on; but having invested in a Gehmann front iris (lovely bit of kit), a x3 eagle-eye and a sun shade, I thought I'd try to make a more representative target to aim at...

...I worked out that at 16' the equivalent size of a 300 yard target black area was 0.39", and that the equivalent of the 600 black was 0.35"...

...is my maths right?...and if it is, does that mean that the 600 yard black is proportionately smaller than the 300 black? (I thought they were the same) - If it is smaller (albeit only by a smidge) , does anyone bother reducing down there front element from their 300 setting? (assuming the same conditions).

I ended up (indoors) setting the front iris at 3.6, which is the same as the 3.0 I would have used normally without the eagle-eye; so it all seemed about right...

...what front aperture sizes do other TR shooters use?


On another point - I can't make my mind up whether I prefer to cover my left eye or not - Do most serious TR shooters cover/blank off their left eye? (assuming right hand)...and what methods do people prefer...covering the eye, in front of the eye, or on the rifle?

Usually shoot with a 3.7 for up to 600x, except in really bright or really dark conditions when I drop to a 3.6. I will say a 3.0 is far too small for 600x!

I have varied from using different ringes at each range to just using whatever happened to be in the rifle! I think it is best to change, both between distances but also for various light conditions and even times of day (late afternoon at Bisley the light can be on the back of the targets, this can cause aiming mark to appear square!).

Dougan wrote:...is my maths right?...and if it is, does that mean that the 600 yard black is proportionately smaller than the 300 black? (I thought they were the same)

I can't remember the dimensions off the top of my head, but the calculations are easy if you have a bible to hand (or online). Obviously the angular dimensions of the aiming mark are different from 500 to 600 (since it is the same physical diameter), and the same goes for the long range target from 800 all the way to 1200, so whether it is the same or close from 300 to 500 is largely incidental. When you scale targets down to very short distances the effects of diffraction will become more significant, so making a directly proportional aiming mark may not results in a useful target. Print a bunch of different aiming marks and try them at typical short range apertures to find one that gives you a reasonable picture. If you are indoors make sure you have plenty of light shining on the aiming mark.

You will probably get a different answer regarding foresight apertures each time you ask the question. It is very personal, so you really need to find out what works for you. For the record my current iris dimensions for different distances are below. These are *very* tight compared to most. By comparison I think GazM uses much larger apertures. Until the rain screwed us both (in very different ways) today we both nearly clean on V's after 2 distances, so both large and small can work if it suits you. In the rain at 600 I could actually see nothing of my aiming mark whatsoever due to a fogged lens, and had to position by waving the sights until I caught a glimpse of the next door target and try to judge by reference. Having been in a position to win the stage, and then nearly deciding to retire, I was delighted to only drop 2 points and still be well-in the grand. I plan to look carefully at dispensing with the lens, at least at short range, to avoid this kind of problem.

0.3 lens:

300x 4.1
500x 4.1
600x 3.8
900x 3.5
1000x 3.5

Gaz wrote:Usually shoot with a 3.7 for up to 600x, except in really bright or really dark conditions when I drop to a 3.6. I will say a 3.0 is far too small for 600x!

That's 'middle of the road' for the various advice I've had on this...and I think you're right that 3.0 is too small...

...I think that some more inexperienced shooters (like myself) like the smaller aperture sizes psychologically, as it gives you the feeling that you're cutting down the margin of error...

...where as some more experience (and successful) shooters trust their skills and go for the better image given by a larger one...

andrewh wrote:I have varied from using different ringes at each range to just using whatever happened to be in the rifle! I think it is best to change, both between distances but also for various light conditions and even times of day (late afternoon at Bisley the light can be on the back of the targets, this can cause aiming mark to appear square!).

I've found changing elements once I'm down a bit of a faff, especially when in a comp and you're holding people up...

...now I've got an easily adjustable iris I'll experiment a lot more, and log it on the score sheet...

rox wrote:

Dougan wrote:...is my maths right?...and if it is, does that mean that the 600 yard black is proportionately smaller than the 300 black? (I thought they were the same)

I can't remember the dimensions off the top of my head, but the calculations are easy if you have a bible to hand (or online). Obviously the angular dimensions of the aiming mark are different from 500 to 600 (since it is the same physical diameter), and the same goes for the long range target from 800 all the way to 1200, so whether it is the same or close from 300 to 500 is largely incidental. When you scale targets down to very short distances the effects of diffraction will become more significant, so making a directly proportional aiming mark may not results in a useful target. Print a bunch of different aiming marks and try them at typical short range apertures to find one that gives you a reasonable picture. If you are indoors make sure you have plenty of light shining on the aiming mark.

You will probably get a different answer regarding foresight apertures each time you ask the question. It is very personal, so you really need to find out what works for you. For the record my current iris dimensions for different distances are below. These are *very* tight compared to most. By comparison I think GazM uses much larger apertures. Until the rain screwed us both (in very different ways) today we both nearly clean on V's after 2 distances, so both large and small can work if it suits you. In the rain at 600 I could actually see nothing of my aiming mark whatsoever due to a fogged lens, and had to position by waving the sights until I caught a glimpse of the next door target and try to judge by reference. Having been in a position to win the stage, and then nearly deciding to retire, I was delighted to only drop 2 points and still be well-in the grand. I plan to look carefully at dispensing with the lens, at least at short range, to avoid this kind of problem.

0.3 lens:

300x 4.1
500x 4.1
600x 3.8
900x 3.5
1000x 3.5

It's encouraging to know that there are experienced shooters who have success with the smaller sizes, as I really have trouble getting on with 4.0+ (or 4.6 with the lens)

I'll have to wait and see (only til tomorrow ) where I end up with the front aperture, and then work back to find the approximate size of a 16' target...it'll be very interesting to see how it compares to the directly proportionate version...


Cheers all for your very helpful responses :cheers:

rox wrote:You will probably get a different answer regarding foresight apertures each time you ask the question. It is very personal, so you really need to find out what works for you. For the record my current iris dimensions for different distances are below. These are *very* tight compared to most. By comparison I think GazM uses much larger apertures.

As Bob says, the choice of apertures is a very personal one and depends on your eyes. The best policy is a lot of trial and error; however I'm not sure that trying to simulate different ranges at home using different-sized spots is going to help because of the light conditions being very different (which massively affects the apparent size of the target) and because of the percentage error.

I currently use a 0.5 lens at all ranges but please find below also the sizes I used to use without a lens...
Dist 0.5 No Lens
300x 5.8 3.8
500x 6.0 4.0
600x 5.5 3.6
900x 5.3 3.4
1000x 5.1 3.2

Hope this helps.

Gaz

contrary to popular belief. bigger is better. once proficient then reduce size. I used to practice 22 with no foresight ! just the tunnel. once you get your head over the 'this won't work' stage you will start scoring 90+. put the FS back in & you will get more :-)

On GB NRA targets, in angular terms the biggest aiming mark is 500x, then 300x, 600x and the long-range targets in distance order (because it's the same physical target all the way back).

As Gaz and Rox say, foresight sizes are partly preference and partly conditions of the day. The theory agrees with Hitchphil that bigger is better, but look at Jane Messer for at least one exception. Jane has won the NRA Grand Aggregate, been on the Palma team for at least 10 years, is the current Palma captain, and shoots with a tiny little foresight.

FWIW, and I'm not in the same league as Gaz or Jane, at each distance I set:

300 4.1
500 4.3
600 3.8
900 3.4
1000 3.1

and then check and adjust on the firing point before I start shooting. I don't use a front lens (I argued strongly against them when the rules permitting them were being formulated) but may be forced by old age to swallow my principles!

Adjusting the rearsight also matters a lot. Broadly, the smaller the better - same principle as a camera that a smaller aperture gives better depth of field - but again the conditions of the day are a big factor, as is the amount of eye relief you have. If you have 2" eye relief, the rearsight will appear 50% bigger than if you have 3" eye relief.

Iain