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Where is the 10m Air rifle distance measured from?

Posted: Thu Jan 05, 2017 12:42 pm
by Schuetz
Where is the 10m Air rifle distance measured from?

From the feet, end of the barrel, other?

Thanks

Re: Where is the 10m Air rifle distance measured from?

Posted: Thu Jan 05, 2017 1:10 pm
by David Levene
ISSF rule 6.4.5.4
"The firing line must be clearly marked. The range distance must be measured from the target line to the edge of the firing line nearest to the athlete. The athlete’s foot or, in the prone position the athlete’s elbow may not be placed on or in front of the firing line."

Re: Where is the 10m Air rifle distance measured from?

Posted: Thu Jan 05, 2017 1:27 pm
by TenMetrePeter
If you want to set up a home range, use a suitable small table and have the edge of the table nearest you exactly 10m from the target. If you stand so that you don't touch the table with your front thigh you are pretty near the rule David has quoted..

Re: Where is the 10m Air rifle distance measured from?

Posted: Thu Jan 05, 2017 1:34 pm
by David Levene
TenMetrePeter wrote:If you want to set up a home range, use a suitable small table and have the edge of the table nearest you exactly 10m from the target. If you stand so that you don't touch the table with your front thigh you are pretty near the rule David has quoted..
That obviously doesn't comply with ISSF rule 6.4.10 b:-
"The nearest edge of the bench or stand must be placed 10 cm forward of the 10m firing line"

Re: Where is the 10m Air rifle distance measured from?

Posted: Thu Jan 05, 2017 1:50 pm
by Schuetz
Thanks for all the replies

Re: Where is the 10m Air rifle distance measured from?

Posted: Thu Jan 05, 2017 2:39 pm
by TenMetrePeter
David Levene wrote:
TenMetrePeter wrote:If you want to set up a home range, use a suitable small table and have the edge of the table nearest you exactly 10m from the target. If you stand so that you don't touch the table with your front thigh you are pretty near the rule David has quoted..
That obviously doesn't comply with ISSF rule 6.4.10 b:-
"The nearest edge of the bench or stand must be placed 10 cm forward of the 10m firing line"
I dont hold ISSF comps in my garage but point taken.

Re: Where is the 10m Air rifle distance measured from?

Posted: Sat Jan 07, 2017 4:52 pm
by Packrat1947
In my basement I have shooting bench. I have long wondered how far from the target face should my rifle be.

To the end of the bbl/bloop tube (i.e. Anschutz SuperAir)?
To the crown on the rifled bbl? The rifled bbl. being about 15" long.
At my feet?
At the front edge of the shooting bench?
At the front sight aperture or scope crosshairs?

If we say, ....at the elbow or such, that is clearly a fudge. It seems the rule makers are not technical shooters.

If I were a rule maker, I would have it to be to the end of the rifled bbl. I mean, that's where the pellet's uncontrolled journey begins no matter what the shooter's position, or the rifle. Use some China marker and mark the bbl. tubing as to the bbl crown. If in the future if someone wants to use a 3 meter bbl. That's fine. Just back him up a bit. That will stop that nonsense in a hurry.

Heck at Camp Perry there was no defined firing line at High Power courses. It was just a 6 ft. berm of dirt. Plop down and shoot wherever you want. There was no painted line or taut cable. Even the newest beginner would look at the situation and say to himself “something is not right here”.

Re: Where is the 10m Air rifle distance measured from?

Posted: Sat Jan 07, 2017 7:37 pm
by Spencer
Packrat1947 wrote:In my basement I have shooting bench. I have long wondered how far from the target face should my rifle be.

To the end of the bbl/bloop tube (i.e. Anschutz SuperAir)?
To the crown on the rifled bbl? The rifled bbl. being about 15" long.
At my feet?
At the front edge of the shooting bench?
At the front sight aperture or scope crosshairs?

If we say, ....at the elbow or such, that is clearly a fudge. It seems the rule makers are not technical shooters...
David has given the answer in the second post in this thread.
Packrat1947 wrote:...If I were a rule maker, I would have it to be to the end of the rifled bbl. I mean, that's where the pellet's uncontrolled journey begins no matter what the shooter's position, or the rifle. Use some China marker and mark the bbl. tubing as to the bbl crown. If in the future if someone wants to use a 3 meter bbl. That's fine. Just back him up a bit. That will stop that nonsense in a hurry...
How would this be enforced?

Re: Where is the 10m Air rifle distance measured from?

Posted: Mon Jan 09, 2017 4:56 am
by Hemmers
Packrat1947 wrote:If I were a rule maker, I would have it to be to the end of the rifled bbl. I mean, that's where the pellet's uncontrolled journey begins no matter what the shooter's position, or the rifle. Use some China marker and mark the bbl. tubing as to the bbl crown. If in the future if someone wants to use a 3 meter bbl. That's fine. Just back him up a bit. That will stop that nonsense in a hurry.
Wha? How on earth would you accurately measure if such a mark was in front of or behind a line on the ground with any accuracy?

The rule is really quite simple. You have a line on the ground and your feet must be behind it. Since there is a limit on the maximum length of the air rifle, no athlete can use a 3 metre rifle. They are at liberty to get as close to the line and to use as long a barrel as the rules allow, or they can stand back/use a shorter rifle if they prefer.
Packrat1947 wrote:Heck at Camp Perry there was no defined firing line at High Power courses. It was just a 6 ft. berm of dirt. Plop down and shoot wherever you want. There was no painted line or taut cable. Even the newest beginner would look at the situation and say to himself “something is not right here”.
High power - what, 300/500/600/1000yds? If you think a foot forward or backward at 500yds gives you any measurable advantage then you're nuts. It's worked fine for 100 years and if there was a case for changing it, then it would likely have been made. Those firing point berms will have been measured out to be straight and square at the point of construction. I mean sure, you could paint a line along the front of it, but why bother - anywhere on the berm is fine.

Now, if it's a safety issue you're concerned about, surely it's easily understood that you don't go forward of the berm, just the same as you wouldn't cross a painted line, but as far as creating a fair and level playing field, it's a non-issue.

Surely you can appreciate that the tolerances increase as the range goes up.

Plus/minus 10cm at 10metres is 1%.

An entire foot at 500yards is 0.06%.

Broadly speaking: no body cares. It makes no difference to your shooting if you, your rifle and your ammo are all working properly.

Re: Where is the 10m Air rifle distance measured from?

Posted: Mon Jan 09, 2017 11:05 am
by tstamey
Well said Hemmers!

Re: Where is the 10m Air rifle distance measured from?

Posted: Thu Jan 19, 2017 9:35 am
by Packrat1947
Well, I guess you are right. The same people are going to win.

Basketball hoops should be an approximates size and almost circular, and high enough. Football goalposts should be almost this wide.

The Wimbledon tennis court should be appoximately to size. And look pretty close to rectangular.

What the heck, .........the same people are going to win.


As an aside, I shot at a local range for about 30 years. One day I decided to do some measurements with a 100 ft. tape. The 100 yd. range was really 104 yds. The 200 range was about 190 yds. We made up some brass markers to locate the proper distances. The range was built in the 40s and someone just stepped it off and said this is good enough.

Re: Where is the 10m Air rifle distance measured from?

Posted: Thu Jan 19, 2017 12:26 pm
by SlartyBartFast
Packrat1947 wrote:As an aside, I shot at a local range for about 30 years. One day I decided to do some measurements with a 100 ft. tape. The 100 yd. range was really 104 yds. The 200 range was about 190 yds. We made up some brass markers to locate the proper distances. The range was built in the 40s and someone just stepped it off and said this is good enough.
Just did all the calculations and accidentally flushed my post. So this rehash is rushed.

Summary: Of course tennis courts are flat ENOUGH, rectangular ENOUGH, and ROUGHLY the right size. All as per defined in their rule book. Line can't be infinitely tight, so the net it tall ENOUGH, and straight ENOUGH. Line painters aren't precision instruments. And when it rains it's obvious the court isn't perfectly flat and both sides aren't identical.

For 300 yd shooting, the difference on target between someone shooting a 10-ring (7 in. on an SR-3 target) on the line at 890 feet (10 feet in front of line) [1] and making the EXACT SAME shot at 910 ft (10 feet behind the line) [2] is 0.1573033707564 in. further from dead center.

A 5.56 is 0.218897 in. or 0.1094485 half dia.
A 7.62 is 0.2999991 in. 0.14999955 half dia.

So, one shooter might gain a point. If that shooter has a 20ft advantage on the other and both shoot the exact same shot.

So, plopping down anywhere on a 6 foot berm, where the maximum difference is half that? The exact same shot would score the exact same.

Unless everyone is shooting ragged single holes, or desperately depending on every shot that barely cuts the edges of higher scoring rings.

In your example, any error or advantage is only relevant if trying to compare scores shot at different ranges. Everyone that competed on 100 yd targets at a distance of 104 yds competed under the same conditions and was equally matched. And unless you've been training at different ranges, would have no effect on you trying to get as good as you can get through training.

When you competed elsewhere you might wonder why your groups are a percentage larger or smaller than normal, or why the target was that percentage smaller larger when aiming. As would people coming to your range. But again, in each case everyone would be competing under the same conditions.

So yes, it was all "good enough".

[1] http://keisan.casio.com/exec/system/1273850202 height = 10680 and base = 7 gives a vertex angle of 0.037553412194 degrees
[2] http://keisan.casio.com/exec/system/1273850202 Vertex angle of 0.037553412194 and height = 10920 gives a base of 7.1573033707564