Off hand resting on top of scope?

[marlinguy]

Resting one hand on top of the scope will not only keep the gun steady, but it can also keep the gun vertical, and avoid canting the gun. Canting isn't a big deal at say 200 yds. or less, but as you stretch shots out much further canting becomes a huge issue to accurate shooting. Many long range shooters add spirit levels to their scopes or iron sights to ensure they don't cant their rifle at all.

[rc]

While not as bad as resting the forfend directly on a table or other hard object when sighting in, I suspect there may be a point of impact shift when shooting in the field if you sight in with your hand putting pressure on the scope at the bench, but not from improvised field positions. I'd be interested if anyone had tried to detect a POI shift with and without pressure on the scope.

[marlinguy]

Originally Posted by rc

While not as bad as resting the forfend directly on a table or other hard object when sighting in, I suspect there may be a point of impact shift when shooting in the field if you sight in with your hand putting pressure on the scope at the bench, but not from improvised field positions. I'd be interested if anyone had tried to detect a POI shift with and without pressure on the scope.

Usually since the scope is mounted to the receiver on bolt action rifles resting your hand on top should not impact point of impact. On older single shot rifles where their scopes were mounted on the barrel this might be a different issue. Especially since those old rifles used two piece stocks, and have different characteristics than a one piece stock. Most old single shots have a sweet spot where the barrel is rested to get best harmonics and best accuracy. Where a one piece stock is never rested on the barrel.

[FrankenMauser]

I'd be interested if anyone had tried to detect a POI shift with and without pressure on the scope.

Depends on rifle, rest, and amount of pressure.

I can shift the POI with some centerfire rifles by forcing contact between the barrel and stock; or just by getting some heat into the barrel.
Examples:
I have an AR with a huge gas block and a very small diameter hand guard (very minimal clearance), as well as an AR with clamshell handguards. I can shift the POI with pressure on those clamshells, or enough pressure to make the handguard contact the gas block.
My .270 Win Ruger 77 Mk II runs high and slightly to one side with heat. Very predictable, but it still shifts. It even has spring and summer shifts from humidity, with a laminate stock(!).

One of my .22 LR match rifles is susceptible to POI shift if excess pressure is put on the fore-end.
Before I opened the barrel channel, it was extremely susceptible and would do it with any pressure, not just 'excess'.
'Hand over the top' was a great way to cause it.

Shooting with a bipod mounted on the factory sling swivel would shift groups up, from the weight of the barrel, alone, flexing the stock into contact with the barrel.
Bags and soft rests closer to the action would also do it, if I was putting pressure on the rifle - even just on the comb with my cheek. I could shift groups left or right by changing the direction from which the pressure was applied.

The vertical shift was generally minor by most people's standards - 1/2" to 3/4" at 50 yd. But when you're shooting 1/4" and 1/2" targets out to 62 yd, 1" targets out to 80 yd, 1.5-2" targets out to 100 yd, and 2-4" targets out to 200 yd, a 1-1.5 MoA shift is going to ruin your match when you inadvertently put pressure on the rifle during the heat of the moment, while on the clock.

[FrankenMauser]

This post was pulled out of the previous, since it is a continuation of the subject, but not necessary to answer the question.

Part 2:

As mentioned in my previous post, back in September, it is pretty common to be forced into positions that require putting a hand over the scope in NRL22, PRS, and some 2- and 3-gun matches. When you shoot matches that require this, and you have a rifle that will shift the POI, it is something that must be fixed (or avoided at all costs).

Tank traps, ladders, certain uses of tires, and some improvised props can force the hand-over-the-top position (or the choice to go over the top is preferable to even jankier options). Not only can they force the hand over the top, but they may require resting the rifle in a manner that is going to have maximum impact when it comes to shifting the POI.
If your rifle can shift the POI - which is something that should be tested for, with some stock styles and materials - you need to do something about it. Or, be always weary, always mindful, and make sure you are not putting pressure on it.

And that finally brings me to the reason why I bought it up again.
There is a very common variation of the hand over the top that is used on ladders and from the shelf on the 'bottom' of some sawhorses, or from some positions on folding chairs. It doesn't really have a name, but we can call it the 'ladder pinch'.

You can see it being demonstrated here at about 1 minute 30 seconds.
https://www.youtube.com/watch?v=XzJSE7ybgJI
And here, from about 6:00 to 7:30.
https://www.youtube.com/watch?v=FTRSlCZJZw0

If the links go down, or someone doesn't have access, the basic principle is: Rifle is rested on prop and slid all the way to the strong side, up against the vertical part of the prop (ladder rail, chair back support, etc.). Support hand goes over the top and grabs the vertical part of the prop, while putting pressure on the scope with hand and wrist, and "locking it in" on the prop. It is a very stable arrangement.
There is a variation of this where the support hand will wrap a thumb around the scope's objective bell, with the fingers over the top, and pinch the ladder between a few fingers in a fist; or the hand is wrapped around the scope, while the thumb and index finger go over the top to pinch the vertical part of the prop.

If you have a rifle that will shift POI, the ladder pinch can be used to pull up slightly, while still providing a very "locked-in" rest position, and reduce pressure on the stock enough to prevent a POI shift. It isn't much of an issue on the ladder, since most rifles can be rested under or very near the receiver. But it can be beneficial on the longer platforms, like a sawhorse shelf or chair seat, that may be causing pressure farther out on the stock.

This is not going to be an issue for shooters with chassis rifles and very stiff stocks.
But it is something that some guys shooting in "factory" classes, or hunters with basic rifles in synthetic stocks, must be mindful about.

[Picher]

My off hand is used to pull the forend downward, concentrating on purely vertical pressure on the front bag. Position of the off hand is just behind the front bag and pulling equally downward with both fingers and thumb. The right hand pulls straight backward on the pistol grip and the trigger finger applies pressure on the trigger exactly backward as well. This results in directly-backward force that blends with the recoil to create straight-back combination of forces that produces beautiful groups on-target.

[44 AMP]

I don't play the shooting games that require me to hold my rifle a certain way, and when I shoot from a bench or other rest, (other then varmint rifles with bipods) my rifle in in my hands. I use the bench or the rest to support me, holding the rifle.

I do it that way because its the one factor I can count on being consistent when I'm shooting in the field, me holding the rifle.

I think what is most important is knowing that changes in the way the rifle is held can change the point of impact, and by how much, so that one can compensate for that.

What ever method you choose to use should be what works best for you. There is no "wrong" if you hit what you're aiming at.

My support hand goes to the top of the scope if I'm adjusting it, then off for the shot. Just my way of doing things.

[FrankenMauser]

I happened to notice this guy's hand on the scope objective bell.
So, here's another time when the shooter is forced, because there's nowhere else for the support hand to go that is beneficial.
About 7:40.
But if you keep watching, you'll see that the same technique is not used when a better position is possible.
https://www.youtube.com/watch?v=20eF84TfOQ4

[Ridgerunner665]

I've made a lot of pretty long shots over the years, both from a bench at the range and from whatever field rest I had available when hunting...if my hand on the scope gives me the best (steady) grip and control for follow through, then that's what I do.

As long as the action to stock interface (bedding, pillars, screws, etc), and scope mounting is in proper order I can't see how it would cause any shift in POI... and it never has, that I've noticed.

Edited to add: On some of the new lower tier guns with plastic stocks, no bedding, and no pillars... yes, there likely would be some flexing of the stock that could cause some shift.

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