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Bore axis height

Posted: Thu Dec 02, 2010 4:27 pm
by schatzperson
I have long ruminated over an objective explanation for match pistol "forgiveness" ( of less than perfect shooter technique);
Reading through an old (2005) thread, I came across a note that might throw some light on this phenomenon.
The thread quote:
"height of the axis of the bore over the hand has to do with perceived recoil and recovery for follow up shots. It has nothing to do with the accuracy of the guns in question."

I often suspected that ANY linear distance between trigger vector(s) and bore axis will insert a turning moment that will conspire to increase error movements immediately after trigger/sear release.
A high bore axis should contribute to this effect.

If this is indeed true, the bore axis height (along with other geometric parameters) WILL have a marked effect on intrinsic pistol accuracy.

What do you guys think?

Posted: Fri Dec 03, 2010 8:34 am
by seamaster
http://www.maennel.at/italia/en/advantages

advantage #4

I am tempted to take out the black plastic insert in my LP10 grip, and make a thinner insert replacement to see if it makes that much of a difference when barrel axis is lowered into the grip.

Posted: Fri Dec 03, 2010 9:20 am
by David Levene
seamaster wrote:I am tempted to take out the black plastic insert in my LP10 grip, and make a thinner insert replacement to see if it makes that much of a difference when barrel axis is lowered into the grip.
Remember that if you do that you will also change the direction of trigger pull slightly. It might be better, it might be worse, but it will change.

Posted: Fri Dec 03, 2010 1:53 pm
by Tycho
Personally, I think that the horizontal distance between hand and chamber is more important than the vertical distance between bore axis and hand. Most pistols that are known to be "forgiving" (if there is such a thing) have the mag in the grip, like the H208 or the FAS 602/607.

Posted: Fri Dec 03, 2010 3:07 pm
by Fred Mannis
Tycho wrote:Personally, I think that the horizontal distance between hand and chamber is more important than the vertical distance between bore axis and hand. Most pistols that are known to be "forgiving" (if there is such a thing) have the mag in the grip, like the H208 or the FAS 602/607.
The Toz, known as a 'forgiving' pistol, has a short horizontal distance between the hand and the chamber. The Morini 84, which is very popular, has a very short distance between hand and chamber. The Pardini K22, which has never been popular among world class shooters, has a considerably longer distance between the hand and the chamber.

Posted: Sat Dec 04, 2010 1:43 am
by JamesH
Fred Mannis wrote:
Tycho wrote:Personally, I think that the horizontal distance between hand and chamber is more important than the vertical distance between bore axis and hand. Most pistols that are known to be "forgiving" (if there is such a thing) have the mag in the grip, like the H208 or the FAS 602/607.
The Toz, known as a 'forgiving' pistol, has a short horizontal distance between the hand and the chamber. The Morini 84, which is very popular, has a very short distance between hand and chamber. The Pardini K22, which has never been popular among world class shooters, has a considerably longer distance between the hand and the chamber.
Mechanically I can't think why that would make any difference.

Posted: Sat Dec 04, 2010 2:40 am
by Doral
If the M.I.T. professor thinks there is a difference, there is a difference.

Posted: Sat Dec 04, 2010 2:44 am
by Tycho
I do... The rear end of the chamber is the point where the impulse from the shot passes to the pistol (lousy english, sorry). If this point is 2x away from the hand, any error back at where the hand holds the pistol (wobble, inconstant holding force etc.) will lead to a deviation from the straight bore line axis that is 2x, too. So the lever at the point of impulse to move the gun from the ideal axis would be 2x, too, so any mistake would be amplified. There are pictures somewhere on the net of a russian / french designed free pistol where the chamber is inside the grip itself, and everybody who shot it apparently said that this was the most forgiving gun they'd ever shot...

Turning moments

Posted: Sat Dec 04, 2010 8:30 am
by schatzperson
I tend to agree with Tycho.
Intuition tells me that there might be a complex set of parameters working here.
For a start, there are basically 2 "originating" forces:
1) finger-trigger-sear/assy (ignition train mechanicals)
2) recoil impulse during dwell time ( bullet in barrel)

ANY distance between the fulcrum ( web of hand?) and force application point WILL have a direct effect on resultant barrel direction.

I find all this rather interesting if a little frustrating too, because little consideration appears to be given to it.
I simply could not resist bringing this up on this forum.

I wonder if perhaps some pistol designers are reading these notes and smiling covertly at my ignorance :-)

Posted: Sat Dec 04, 2010 8:38 am
by Fred Mannis
Doral wrote:If the M.I.T. professor thinks there is a difference, there is a difference.
??