Rifle scopes you'd love to see Form test

[Billy Goat]

Think in terms of the "equal and opposite reaction" goes somewhere. Despite the lead sled not seeming to move, the recoil pad would have some give and that puts a lot of stress into the rifle and scope attached to it. The same recoil energy is spread over a small fraction of time compared to shooting off bags. More peak force of deceleration.

It's equal and opposite, but if it doesn't have enough energy to overcome what is holding it, then there's no movement.


Possibly the recoil pad would allow some movement, but I think the real dangers are to the stocks around recoil lugs and pillars.

 

[SDHNTR]

I overhead a guy at a gun counter say that lead sleds destroy scopes. Made no sense to me. He said that when a gun isn't allowed to recoil all the recoil goes into a scope.

Recoil is g-forces created, if the gun isn't moving, there's no g-forces.

Now bedding and lug areas I can see taking heavy abuse, but I don't get the idea it will damage a scope. Only if I guess the gun isn't held properly and it does recoil some distance and then encounters a hard stop.



I chocked it up to being the same as so much other gun counter advice.

That guy was mostly correct. It’s basic physics. You are talking about two independent masses, gun and scope, with inertia forcing them in two opposite directions. A lead sled abruptly stops the inertia of one mass (the rifle), but not the scope (and especially scope internals like the erector tube), going the other direction (forward). It forces the mass of the objects to separate abruptly, instead of moving together as one unit (like it does agains your soft shoulder). This absolutely does cause excess unnecessary stress and can cause damage to the scope and mounting system.

 

[Billy Goat]

That guy was mostly correct. It’s basic physics. You are talking about two independent masses, gun and scope, with inertia forcing them in two opposite directions. A lead sled abruptly stops the inertia of one mass (the rifle), but not the scope, going the other direction (forward). It forces the mass of the objects to separate abruptly, instead of moving together as one unit (like it does agains your soft shoulder). This absolutely does cause excess unnecessary stress and can cause damage to the scope and mounting system.

Problem is the lead sled doesn't cause it. It's the initial firing that does. The scope and firearm are at rest, the firing creates the initial g-forces.


If it can't hold up to a lead sled, then it just can't hold upto recoil. The first reward movement will be the strongest. The reverse action of it stopping and going forward again will be less force because some of the energy is absorbed within the initial reward movement.

 

[SDHNTR]

Problem is the lead sled doesn't cause it. It's the initial firing that does. The scope and firearm are at rest, the firing creates the initial g-forces.


If it can't hold up to a lead sled, then it just can't hold upto recoil. The first reward movement will be the strongest. The reverse action of it stopping and going forward again will be less force because some of the energy is absorbed within the initial reward movement.

It’s not what starts the inertia (the cartridge firing) that causes the damage, it’s what stops it (the lead sled). Have you ever seen a professional bench rest shooter or anyone other than a pure weekend warrior amateur at a local range using one? Nope. People who know, don’t. Case closed.

 

[Billy Goat]

It’s not what starts the inertia (the cartridge firing) that causes the damage, it’s what stops it!

But I thought it was about the scope being at rest and having forces applied against it.

Instead it's the inertia of the scope being stopped?

Seems to me the forces it takes going from zero to whatever are worse than whatever to zero.

 

[Billy Goat]

If a lead sled eats scopes, then it seems these 25-35# PRS guns should too. We all need 7# guns so our scopes are saved?

 

[SDHNTR]

But I thought it was about the scope being at rest and having forces applied against it.

Instead it's the inertia of the scope being stopped?

Seems to me the forces it takes going from zero to whatever are worse than whatever to zero.

No, because there is no reversal of inertia of the scope. The force of it doesn’t start going backwards and then reverse as you are thinking. That’s what you are missing. The moment you ignite that round, the inertia of the scope wants to move forward while the rifle moves backwards. Abruptly stopping the direction of the rifle moving backward, also abruptly stops the inertia of the scope moving forward. And with the scope there’s nothing to absorb that inertia like a shoulder or back of the sled. That mass wants to keep moving, tearing the guts apart. Since the mounts hold onto the exterior of the scope, it’s the internals that bear the brunt of this inertia slamming to a stop. It’s like how a fast moving car stopping abruptly, throws the internals (passengers) around in the opposite direction of the applied force violently and causes bodily damage.

 

[SDHNTR]

If a lead sled eats scopes, then it seems these 25-35# PRS guns should too. We all need 7# guns so our scopes are saved?

No, the opposite. Since the weight of that heavy gun absorbs the inertia. The opposing forces are lessened. The worst case scenario is a light rifle, a heavy scope, and weak mounts!

Think Tikka Superlite in a magnum cartridge, a big 34oz Nightforce, and Talley Lightweights! Not a good mounting system.

 

[Billy Goat]

No, because there is no reversal of inertia of the scope. The force of it doesn’t start going backwards and then reverse as you are thinking. That’s what you are missing. The moment you ignite that round, the inertia of the scope wants to move forward while the rifle moves backwards. Abruptly stopping the direction of the rifle moving backward, also abruptly stops the inertia of the scope moving forward. And with the scope there’s nothing to absorb that inertia like a shoulder or back of the sled. That mass wants to keep moving, tearing the guts apart. Since the mounts hold onto the exterior of the scope, it’s the internals that bear the brunt of this inertia slamming to a stop. It’s like how a fast moving car stopping abruptly, throws the internals (passengers) around in the opposite direction of the applied force violently and causes bodily damage.

How is there separate inertia in the scope and the rifle?

Is there elasticity between them?


They should be tied together, experience the same forces of inertia.


I guess if you have weak mounts there's a possibility, but I think that's an inherent weak point in the whole system then.


Which is the point of pointing out that a scope should handle the recoil from a lead sled. It's a cop out.

 

[SDHNTR]

How is there separate inertia in the scope and the rifle?

Is there elasticity between them?


They should be tied together, experience the same forces of inertia.


I guess if you have weak mounts there's a possibility, but I think that's an inherent weak point in the whole system then.


Which is the point of pointing out that a scope should handle the recoil from a lead sled. It's a cop out.

Yea there is some elasticity. Steel and aluminum stretch and move. That’s why mounts break and work loose. It’s not one solid cohesive system. And it’s especially the guts inside a scope (that you can’t see) that really move. The internal erector tube floats inside the exterior tube, cushioned by various forms of weak, tiny springs. Slam those parts around violently enough and you will have failures.

 

[Billy Goat]

Yea there is some elasticity. Steel and aluminum stretch and move. That’s why mounts break and work loose. It’s not one solid cohesive system. And it’s especially the guts inside a scope (that you can’t see) that really move. The internal erector tube floats inside the exterior tube, cushioned by various forms of weak, tiny springs. Slam those parts around violently enough and you will have failures.

Steel and aluminum can move, they don't always move.


If aluminum moves it will fatigue and rupture.


I'm not saying you are wrong, what I'm seeing is trying to say there's higher forces in the rebound than in the initial start. The start, which is the firearm moving backwards or trying to, is the highest force, the forces reduce fin every reaction after that. If the rebound is what does the damage, which I can see, I still think it's a weak point. Much like dropping them a short distance and they don't hold zero.

 

[SDHNTR]

Maybe this helps. See that internal tube? It holds the goods that actually make a scope work. It’s basically floating inside the main exterior tube on little springs. An independent mass. Picture that sucker getting violently slammed around inside that tube.

 

[SDHNTR]

Steel and aluminum can move, they don't always move.


If aluminum moves it will fatigue and rupture.


I'm not saying you are wrong, what I'm seeing is trying to say there's higher forces in the rebound than in the initial start. The start, which is the firearm moving backwards or trying to, is the highest force, the forces reduce fin every reaction after that. If the rebound is what does the damage, which I can see, I still think it's a weak point. Much like dropping them a short distance and they don't hold zero.

I don’t disagree with it being a weak point, it definitely is. To understand the physics though, you need to get your head around the fact that as the rifle starts moving backwards, the guts of the scope are moving forward immediately. They are essentially floating parts. Make the inertia of floating parts stop abruptly instead of fluidly and they will eventually come apart, if not immediately.

And to your point about aluminum…. This is what eventually happens to heavy scopes in aluminum mounts.

 

[Billy Goat]

@SDHNTR

So here's my point.

I have no doubt whatsoever that a lead sled will destroy some scopes, I don't know that those scopes would actually be durable long term. Now part of that will be based on overall forces too.


I think about the worst thing you could do to a scope is to have the butt of a firearm about 1/2 inch from a solid concrete wall and pull the trigger. Having it tight in a lead sled I don't think puts near those inertia forces on the internal of a scope.



So I think we (I would like) to propose another portion to Form's scope tests. We need a butt drop. I have had different instances of my gun dropping a relatively short distance onto the butt, apparently this is a direction of weakness for scopes if lead sleds are destroying them. Perhaps I'm just expecting too much, however I'd be interested to see if there's a similar failure rate and success rate of scopes holding zero as with other drop tests.

 

[stanginthe11s]

just to stir this pot, the scope internals are not actually moving. in fact, it is standing still. an object at rest tends to stay at rest.

 

[Billy Goat]

just to stir this pot, the scope internals are not actually moving. in fact, it is standing still. an object at rest tends to stay at rest.

I was going to say that, but what is meant is they are moving forward in relation to.



I'm not always correct in how I might type something out, but I hope when I'm off slightly in how I was wording it, someone can interpret what I was trying to say.

 

[SDHNTR]

just to stir this pot, the scope internals are not actually moving. in fact, it is standing still. an object at rest tends to stay at rest.

True, until the entire unit is no longer at rest.

 

[SDHNTR]

@SDHNTR

So here's my point.

I have no doubt whatsoever that a lead sled will destroy some scopes, I don't know that those scopes would actually be durable long term. Now part of that will be based on overall forces too.


I think about the worst thing you could do to a scope is to have the butt of a firearm about 1/2 inch from a solid concrete wall and pull the trigger. Having it tight in a lead sled I don't think puts near those inertia forces on the internal of a scope.



So I think we (I would like) to propose another portion to Form's scope tests. We need a butt drop. I have had different instances of my gun dropping a relatively short distance onto the butt, apparently this is a direction of weakness for scopes if lead sleds are destroying them. Perhaps I'm just expecting too much, however I'd be interested to see if there's a similar failure rate and success rate of scopes holding zero as with other drop tests.

I hear ya. It’s admittedly a silly point to argue and no need to keep going. I agree that scopes should hold up to a Lead Sled. They should hold up to a lot of stuff, but like Form has demonstrated, many unfortunately don’t. Hopefully manufacturers are listening and are now taking durability into account more. It’s should be THE number one consideration.

 

[stanginthe11s]

lol, I knew what both meant hence the stir the pot comment. also, I'm not a believer on the leadsled being the destroyer. simply because to have inertia there has to be movement, if the leadsled mitigates recoil then it is preventing movement therefore no inertia can be applied. so, I would think there would be less inertia with a sled than a person. also, I believe to calculate inertia you need both speed and distance since the scope internals do not accelerate at the same speed as the rifle so in a shorter amount of time the internals may not have reached max velocity. I also agree the rebound hurts many lesser scopes, something with the way they are designed doesn't handle that movement. that's why springer air rifles are known to tear up scopes.
also, I have never used a sled, and completely suck at explaining things so I may be completely wrong or missing a part of the equation. also, I did not read all of this thread so feel free to yell at me lol.

 

[SDHNTR]

lol, I knew what both meant hence the stir the pot comment. also, I'm not a believer on the leadsled being the destroyer. simply because to have inertia there has to be movement, if the leadsled mitigates recoil then it is preventing movement therefore no inertia can be applied. so, I would think there would be less inertia with a sled than a person. also, I believe to calculate inertia you need both speed and distance since the scope internals do not accelerate at the same speed as the rifle so in a shorter amount of time the internals may not have reached max velocity. I also agree the rebound hurts many lesser scopes, something with the way they are designed doesn't handle that movement. that's why springer air rifles are known to tear up scopes.
also, I have never used a sled, and completely suck at explaining things so I may be completely wrong or missing a part of the equation. also, I did not read all of this thread so feel free to yell at me lol.

Haha. The crux of this entire thread string of bullshit is throw the lead sled in the trash, and shoot off front and rear bags! Or a bipod and rear bag if that’s what you use in the field. Wear a pussy pad on your shoulder if you need to. I can shoot 50+ rounds out of my unbraked .338wm with one on.