Understanding the physics of it...
Hmmmm............. as much as I hate to be raining on Norma Academy's parade, the reality is that
a hand loop like this is entirely useless, and
BeeMaa's conclusion "another piece of gear that would end up in a drawer" is correct...
Here is why:
When shooting a rifle, the butt rests on the shoulder. This contact point is also the pivot point upon which the stock rests, relatively stably, as the muzzle wobbles.
The support hand that holds the rifle forearm is also attached to the same shooter's shoulder that holds the rifle butt. Therefore, the rifle and the support hand are free to wobble together because they only have one shared attachment and pivot point at the shoulder. Tying the hand to the forearm with a hand loop does not change any of this.
When a shooter uses an elbow rest, whether it be on the ground when shooting prone, on the knee when shooting kneeling or seating, or on a support (e.g. tree branch or rock) when shooting standing, a second contact point is created half way between the butt and the muzzle. However, the elbow itself being flexible, it constitutes another pivot point, and this allows the muzzle to still wobble, although less than if the elbow is not used, because the second pivot point is now closer to the muzzle.
The purpose - and the physics - of the shooting sling, whether it be a competition sling wrapped around the bicep close to the shoulder joint, or whether it is a military or hasty sling wrapped under the bicep close to the shoulder joint, are:
- to use the relatively stable shoulder as the first point of a support triangle for the rifle forearm;
- to use the fairly stable elbow anchor point as the second point of a support triangle for the rifle forearm;
- to create a mechanical link between the shoulder and the sling attachment point so that the third point of the triangle, the sling attachment point, is stable, being forced into a fixed position at the end of the fixed-distance arm and the fixed-distance sling.
With a sling under proper tension, the butt of the rifle is at a relatively stable point on the shoulder; the elbow is at a fairly stable point on the ground, on a knee, or on some form of support; and the support hand is a fairly stable support point at the end of the arm and the end of the sling.
This is why, as
BigSteve57 and
Nyati rightly emphasize, the sling must be properly tensioned. If it is too long and loose, it does not retain the support hand from moving forward and does not stabilize the third point of the support triangle; and if it is too short, it bring the third point of the triangle too close to the second point and reduces the stability of the support triangle.
View attachment 375650
Once the physics of the application of forces in the sling technique are understood, it is easy to conclude that:
- Using a sling without an elbow rest is virtually useless, save for the psychological placebo effect;
- Using a hand loop that only involves the support hand is completely useless, save for the psychological placebo effect.
In both cases, the rifle and support arm still wobble freely around the shoulder pivot point...
And obviously, as previously noted, attaching the sling to the barrel defeats the purpose because a properly tensioned sling will flex even competition bull barrels...
