10m Olympic shooters Use compact or standard Length?

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Gwhite
Posts: 3427
Joined: Sat Sep 04, 2004 6:04 pm
Location: Massachusetts

Re: 10m Olympic shooters Use compact or standard Length?

Post by Gwhite »

deadeyedick wrote: Fri May 08, 2020 1:43 am I would like to see the scatt readout with barrel weights on the short barrel or alternatively the long without weights....apples for apples.
The moment of inertia increases as the square of the radius to the weights. Two pistols with the same mass can have significantly different moments of inertia if one has the weights further forward.

From: viewtopic.php?f=4&t=55605&p=268248#p268248
Here's the way the physics works:

The pivot point for supporting the pistol is roughly at the wrist joint.

The "moment" of a small weight (mass "M") at a radius "R" from the pivot is just MxR. Gravity pulling the mass down will produce a torque that's going to add to the muzzle heaviness. Doubling the weight has the same effect as doubling the radius.

The "moment of inertia" is a measure of how much the pistol will resist forces that want to make it wobble around. This is equal to MxR^2 (squared).

If you double the mass, the moment of inertia doubles. HOWEVER, if instead you double the radius, the moment of inertia goes up by a factor of FOUR!

Basically, you can double the moment of inertia while keeping the moment the same by cutting the weight in half and doubling the radius. This means that if the pistol is too muzzle heavy for you, it's better to keep the weight as far forward as possible, and reduce the weight until the balance is manageable.

The limit to how much benefit the weights can produce for you is really set by how muzzle heavy the pistol can be without wearing you out over a match. That is why nobody can tell you how to set them up. It's a VERY individual matter, and will also vary with time as your fitness level fluctuates.

YMMV (your moment may vary)
atomicgale
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Location: Copperhill Tennessee USA (a registered CERCLA superfund site)

Re: 10m Olympic shooters Use compact or standard Length?

Post by atomicgale »

Here's long v compact side-by-side:

Image

In this instance, both front sights have been moved back "low-rider style." In lieu of longer sight radius, a "fatter" appearing front sight is established; a 5.0mm on the Steyr and a 5.5mm on the Morini Compact. (I'll run a 6.0mm on a Morini standard length - set to end of barrel - no proven benefit other than apparent front sight width against 59.5mm target.)
spektr
Posts: 887
Joined: Mon Jan 21, 2013 9:53 pm

Re: 10m Olympic shooters Use compact or standard Length?

Post by spektr »

Gwhite wrote: Thu May 07, 2020 7:55 pm The physics says that everything else being roughly equal, the added mass out front provided by a longer pistol will increase the moment of inertia. That means for a given wobble force from the shooter, the pistol will move less. As long as you've trained enough to deal with the added weight and muzzle heavy balance, the more mass you can move forward and the further out you put it, the more stable the pistol will become.
AARRRRRRGGGGGGG

Is it that OR is it that the gun with the higher moment of inertia accelerates/decelerates slower than a lower moment pistol...... If the displacement force was a constant both guns would move the same amount, but unit time would be diffent. This is not a fine point IMHO in the face of a constantly changing displacement force and direction and frequency. The slower the gun responds to displacement, the shorter distance it moves and the smoother its movements appear in tbe sights, advantage to the solid holders......
Conversely, less solid holders may benefit from a gun with a lower moment since they can get it to change direction and get back on target more quickly at the peril of more succeptability to trigger action displacements.....
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