calculating correct insert size

[yana]

I'm shooting an informal 6yrd competition.
I used to only have upto 4.6 size inserts. But these do not give any white around the target.
I than bought sizes upto 5.0 but to my surprise, it doesnt really make much difference at this short(er) distance.
Is there any way to calculate what approx size I'd need to get me some white around the target?
Dont feel like spending another $$$ on inserts that dont make a difference..
Normal inserts wont even be available in sufficient size, but the plastic one's go upto 100 size

[redschietti]

Im sure math could figure it out but i used a drillbit when i had the same question. Just using my fingers and a bit i was able to make a usable insert from what i had. When i figured out what i wanted i ordered a nice one!

[Tim S]

How big is the target in relation to the standard 10m? If you have a preferred size for 10m it should be very simple to translate this to the 6yard target.

[yana]

I dont think the old black inserts can be sized enough.
Thats only possibly with the massive plastic newer inserts.
9 outa 10 of my rifles use the old black inserts

[Tim S]

I dont think the old black inserts can be sized enough.
Thats only possibly with the massive plastic newer inserts.
9 outa 10 of my rifles use the old black inserts

Hi Ends will go large enough. If you calculate the size you need based on the target size-distance vs another rifle you only need to buy one glass insert. Job done.

[yana]

Size needed is 9.2-9.4 (I prefer the cards with more black rings vs the half sizes one's).
I can get those in plastic inserts, but I'll need a bunch of screws to have the other rifles take glass/plastic inserts

[Tim S]

9.2mm is a very large aperture. You're shooting at a 10m target at 6 yards I presume, not a scaled down target?

What screw do you need for glass inserts? These are threaded already, just screw out the retaining clamp for the metal element and screw in the glass. You could just set up a single rifle for 6 yards, not all your rifles.

[Shooter]

Why bother with math and so on? Just try the inserts until one looks right and use it!! No big deal. Don in Oregon

[Tim S]

Why bother with math and so on? Just try the inserts until one looks right and use it!! No big deal. Don in Oregon

Because the OP only has up to 5.0mm, and does not wish to buy unnecessary elements. Besides who sells element sets inckuding 9mm +?

[corning]

I've scanned this thread. A key piece of information missing is what size front globe are you using? Also, what type/manufacture is the globe? I was recently shooting a Palma match, and a friend of mine had inserts up to 7.4mm. He was using these inserts in a 30mm right sight. I believe he said he purchased/had made the inserts by Scott Riles in California. The inserts were plastic.

[yana]

Yes the outer size probably is like original 10m target. Hence the large size insert.
Dont know wether you can use glass one's with standard M18 screws?
With the old black inserts, you only unscrew a little, untill you can switch them out.
The slot isnt large enough for modern inserts.
And the inner of the M18 screw doesnt always take the glass inner (too small)
I almost only shoot the 6yrd so its no problem to adjust them all to 6yrds.
I use:
Tau mk300
Tau mk200
Tau 200Sr
Tau 200Jr
Alfa Proj CO2 rifle
Maybe Walther LG300

Correct about buying of inserts; no one stocks those sizes to try, so I have to buy than try. Those plastics cost E5 a piece for each size.
That x 6 for the above rifles gets pretty expensive

[NMC_EXP]

yana

Art Neergard of Shooting Sight created a spreadsheet which calculates the width of the ring of white between the inside diameter of the front sight aperture and the outside diameter of the bullseye. From what I see, the spreadsheet appears to provide accurate solutions.

Required inputs are:

1. Distance from aiming eye to front sight.

2. Diameter of the bullseye.

3. Distance to target.

4. Magnification (if any) used in either front or rear sights.

A three Minute of Angle (MOA) wide line of white is fairly common. If you provide the data inputs I can run the numbers and suggest a front aperture diameter which provides a three MOA (or any width) line of white.

[GaryN]

Rather than larger diameter inserts, why not scale down the targets, and print your own 6m scaled targets?
Then you use approximately the same size insert as you do at 10m +/-. And these would be standard size inserts.

[TenMetrePeter]

I know this thread is 3 months old but I couldn't believe what was being suggested with big inserts.
Just buy 6 yard targets. The whole point of using 6 yard targets is you use the same sights and the scoring is scaled!
If there are no european 6yd targets try UKs NSRA shop
code Air7

20161110_181050.png

[David Levene]

The whole point of using 6 yard targets is you use the same sights and the scoring is scaled!
If there are no european 6yd targets try UKs NSRA shop
code Air7

Neither the aiming mark nor the scoring rings of the Air7 are proprtionate to the ISSF 10m Air Rifle target.

The aiming mark on the 10m target is 30.5mm diameter. The proportionate size for 5.4864m (6 yard) would be 16.73352mm. The actual diameter of the aiming mark on the Air7 is 16mm.

That's fairly close, but the scoring rings are way off.

If we look at scoring a 9: on a 10m target the centre of the hole must be (5.5 + 4.5)/2 = 5mm from the middle of the target.

If the Air7 target was proportionate then, to score a 9, the centre of the hole would need to be 2.7432mm from the middle of the target.

To actually score a 9 on the Air7 the centre of the hole needs to be (6.0 + 4.5)/2 = 5.25mm from the middle of the target.

That's nowhere near.

You would expect all of the scoring rings on the Air7 6 yard target to be smaller than the equivalent rings on the 10m target. In fact they are all 0.5mm larger.

[TenMetrePeter]

I didnt say exactly proportionate I said scaled. If you wanted exactly proportionate you would need to use a smaller pellet. Point was nobody in our club changes inserts between 6y and 10m because the aiming marks are scaled, we just have 2 sets of rearsights to take care of the inch or so height correction.

[David Levene]

I didnt say exactly proportionate I said scaled. If you wanted exactly proportionate you would need to use a smaller pellet. Point was nobody in our club changes inserts between 6y and 10m because the aiming marks are scaled, we just have 2 sets of rearsights to take care of the inch or so height correction.

To say that the scoring is scaled would indicate that it's somewhere near, and it isn't in this case.

The reason for using the centre of the hole rather than the ring diameter is that it removes the need to use a smaller projectile.

As I said, the aiming marks are fairly close to being scaled. The scoring rings however are larger on the Air7 than on the 10m, rather than being considerably smaller. To describe the scoring as scaled is therefore highly questionable.

[TenMetrePeter]

yes yes yes. Scoring was the wrong word. Should have said "aiming marks". mea culpa.
Turning back to the TOPIC of the thread, do you agree that use of Air7 targets at 6yd means you can use the same foresight inserts as Air 3/89 at 10m?
(apologies to non Brits)
yes or no will do.

[David Levene]

yes or no will do.

No idea I'm afraid. I'll leave that to the experts in shooting rifle.