TargetTalk

Can anyone clarify the history of skid gauges in ISSF?

I've had it in my head that a skid gauge should be 1.5 times calibre diameter, possibly from other disciplines such as NRA, blackpowder etc.
Has it changed at some point or am I continuing to lose my mind?

7mm for .22 (5.5mm) and 11mm for centrefire seem harsh - a slightly precessing .38 can easily make a mark wider than 11mm for example.

JamesH wrote:Has it changed at some point or am I continuing to lose my mind?

I wouldn't argue on either point James ;-)

It's certainly been 7mm and 11mm since I started shooting, and that's before you jumped ship and deserted us in the UK.

JamesH wrote:...a slightly precessing .38 can easily make a mark wider than 11mm for example.

Skids and 'topples' leave different holes.

I think "1.5X the bullet diameter" is just a handy rule-of-thumb to "bullseyesplain" the rule to US pistol shooters, who are used to slow-turning targets, and skidders getting point-of-entry-plus-one.

(Full disclosure: I'm one of them.)

7 and 11mm is all I've ever been aware of, once I read the rulebook.

Spencer wrote:

JamesH wrote:...a slightly precessing .38 can easily make a mark wider than 11mm for example.

Skids and 'topples' leave different holes.

True, but the rules don't differentiate.

David Levene wrote:I wouldn't argue on either point James ;-)

I got one out of two, I'm going to call that a good result.

It's certainly been 7mm and 11mm since I started shooting, and that's before you jumped ship and deserted us in the UK.

The UK was glad to see the back of the H family, we might be coming back for a visit - you have been warned.

JamesH wrote:

Spencer wrote:

JamesH wrote:...a slightly precessing .38 can easily make a mark wider than 11mm for example.

Skids and 'topples' leave different holes.

True, but the rules don't differentiate.

Nope!
Shots fired while the target is in motion (i.e. skid shots) are measured with a skid gauge 6.14.13.1; topples are not.

Being facetious and pedantic how do you tell the difference?

I know and you know the difference in the mark between a skid and a topple but I don't think 'the rules' clearly define them.

JamesH wrote:Being facetious and pedantic how do you tell the difference?

I know and you know the difference in the mark between a skid and a topple but I don't think 'the rules' clearly define them.

Skid Shots
a) Shots fired while the target is in motion must not be scored
as hits unless the greatest horizontal dimension of the bullet
hole (surface lead/bullet marking on the target is ignored) is
less than 7.0 mm in the 25m rimfire 5.6 mm (.22” cal.)
events, or 11.0 mm in the 25m Center Fire Pistol event; and
b) The horizontally elongated bullet hole in the target must be
measured with a skid gauge. When the inside edge of the
engraved lines on the skid gauge touches a scoring ring, the
score will count as the higher value of the two zones.

A topple "almost" never keyholes horizontally...
But now that you mentioned it, it's a hard one to judge if it does keyhole horizontally.

We know that a skid tends to give an elongated oval hole, and a topple an almost normal hole with a smudge, what about the bullet going fully sideways?
That would be an 'elongated hole'.

JamesH wrote:We know that a skid tends to give an elongated oval hole, and a topple an almost normal hole with a smudge, what about the bullet going fully sideways?
That would be an 'elongated hole'.

It would?

As an aside to this topic, 'topples' seem to come and go in cycles. As a scorer one will go through a period when any topple is comment-worthy; and periods when they are commonplace.
I remember doing some accuracy testing with .22LR pistol at 50m and having maybe 20% of the bullet holes showing toppling to some degree (some almost completely sideways) without any noticeable loss in accuracy.

Spencer wrote:

JamesH wrote:We know that a skid tends to give an elongated oval hole, and a topple an almost normal hole with a smudge, what about the bullet going fully sideways?
That would be an 'elongated hole'.

It would?

We're getting into semantics here.

I suppose a hole is a hole - who is to say its a hole or an elongated hole?

A wadcutter bullet travelling sideways makes a wide rectangular hole which has not been elongated but which would fail the skid gauge.
A wadcutter bullet travelling forwards through a target which has turned a little would make a wide oval hole which has been elongated which would fail the skid gauge.

I am trying to be annoying here, but also think the rule is a little woolly.

We all know the answer but how you define it is not clear.

JamesH wrote:A wadcutter bullet travelling sideways makes a wide rectangular hole which has not been elongated but which would fail the skid gauge.

but obviously not when the target is not in motion so the skid gauge would not be used.

JamesH wrote:A wadcutter bullet travelling forwards through a target which has turned a little would make a wide oval hole which has been elongated which would fail the skid gauge.

not oval - obloid

JamesH wrote:I am trying to be annoying here,...

fairly sucessfully

JamesH wrote:We all know the answer but how you define it is not clear.

Given that :
- these days the ISSF is unlikely to be too concerned with paper targets, and
- we do not need another 20 pages of clarification to something that is not a major problem at competitions,
I will not hold my breath.

Spencer wrote: Given that :
- these days the ISSF is unlikely to be too concerned with paper targets, and
- we do not need another 20 pages of clarification to something that is not a major problem at competitions,
I will not hold my breath.

+1

I have been a shooter for 29 years and a referee/judge for most of that time. I have never had a problem differentiating between a "topple" and a late shot. Also, if someone fired a late shot you usually heard it and know to look for one.

Rune Kanstad wrote:I have been a shooter for 29 years and a referee/judge for most of that time. I have never had a problem differentiating between a "topple" and a late shot. Also, if someone fired a late shot you usually heard it and know to look for one.

Yes, but the rules don't clearly state how.

True. But a combination of experience and common sense should make up for it. At least, it hasn't been a problem so far. And I compete in Centrefire, Sport Pistol, Standard Pistol and Military Rapid Fire as often as I get the chance.

Given that :
- these days the ISSF is unlikely to be too concerned with paper targets, and
- we do not need another 20 pages of clarification to something that is not a major problem at competitions,
I will not hold my breath.

How simple. Surely this answers everything.