Mr transformer
Member
- Joined
- Jun 21, 2011
- Messages
- 48
It has always made me wonder why some people constantly have cheap scopes(or brands of scopes) fail, and the replacements for the failed scope will also fail, while some use them for decades on high powered rifles with utmost reliability. I have seen the same things happen with local hunters as I have read on various BBSs
Something dawned on me while typing out a response to another thread talking about scope creep on a 22LR.
From my mechanical experience. When you apply quick acceleration/deceleration to an object, if there is anything mounted to that object that can shift and bounce around, It will suffer far more damage than if it is solidly bolted down.
When you fire a 22 with a straight dovetail with loose mounts, the gun moves under the scope and the scope walks off the mounting rail.
When you fire a center fire gun with a weaver rail that has a recoil lugs on the rings. The gun starts moving through an acceleration curve as the bullet leaves the barrel. If the scope mount has any movement at all under those high Gs. The rifle will start moving before the scope. When lug on the ring bottoms out, then the scope is jolted up to the velocity of the rifle. The impact acceleration on the scope will be many many times the G force induced into the rifle from the recoil acceleration. It won’t be a high speed acceleration, it will be more like a shockwave going through the scope.
You may think the ring is tight. It never goes anywhere because the lug stops it from moving. But every time you fire, the scope is bounced back and forth. Every time you fire, it’s like hitting it with a hammer.
Kind of like seat belt in a car. If the car comes to a quick stop, and you keep moving until you hit the windshield, you will be hurt bad. If you are strapped to the vehicle and slow down the same speed as the vehicle, then you will survive.
The reason I mention this, is I have seen polishing effects from slight movement on weaver/picatinny scope mounts. The scope appears tight, but when you remove it after use, the contact points are shiny like the mount has be shifting back and forth a fractional amount every shot. Not enough to loosen up, but enough to see the effects. And that is with factory specified torque.
That leads me to the idea that a lot of the scope failures people see is not caused by the scope, but caused by the mount. If the scope is heavy enough that the mounting ring does not have enough torque enough to restrain it. It may break where a smaller scope will be fine with the same installation.
Just because you think it’s solidly mounted, doesn’t mean that it isn’t moving.
The term I can think of that can describe it is ….. “scope slap”
That may explain why some people have no problem with a cheap scope on a magnum rifle, while other people have one after another of the same type scope fall apart with five or six shots.
When they buy a cheap scope, they will use cheap rings that is often purchased with the scope. When they spend a big chunk of money on an expensive scope, normally they will buy equal quality rings to mount it.
Some people mount a cheap scope with expensive rings. Either because they already have the rings, so why not use them, or the gun they have, requires custom rings that is needed to fit a scope to that rifle.
So, the one that uses good rings/mounts with a cheap scope, has no problem. The person that used the cheap mounts/rings with a cheap scope has it fall apart in 6 shots.
Basically, you may be able to cause a scope to break by not having the mounting bolts tight enough. Or having a weak flimsy mounting ring that will flex under the recoil jolt
Grind the recoil lugs off a set of rings and mounted them on a rifle with the scope in question. If the scope moves after several shots, then you don’t have the bolts tight enough. If you can’t tighten them enough to keep it from moving, then the rings are not strong enough to mount the scope you have. The bigger scope, the higher torque you will have to have.
If you don’t have it tight enough and rely on the recoil lug to stop it, you may be pounding the scope to death.
That would explain a lot of what i see on the web......
What do you people think?
Something dawned on me while typing out a response to another thread talking about scope creep on a 22LR.
From my mechanical experience. When you apply quick acceleration/deceleration to an object, if there is anything mounted to that object that can shift and bounce around, It will suffer far more damage than if it is solidly bolted down.
When you fire a 22 with a straight dovetail with loose mounts, the gun moves under the scope and the scope walks off the mounting rail.
When you fire a center fire gun with a weaver rail that has a recoil lugs on the rings. The gun starts moving through an acceleration curve as the bullet leaves the barrel. If the scope mount has any movement at all under those high Gs. The rifle will start moving before the scope. When lug on the ring bottoms out, then the scope is jolted up to the velocity of the rifle. The impact acceleration on the scope will be many many times the G force induced into the rifle from the recoil acceleration. It won’t be a high speed acceleration, it will be more like a shockwave going through the scope.
You may think the ring is tight. It never goes anywhere because the lug stops it from moving. But every time you fire, the scope is bounced back and forth. Every time you fire, it’s like hitting it with a hammer.
Kind of like seat belt in a car. If the car comes to a quick stop, and you keep moving until you hit the windshield, you will be hurt bad. If you are strapped to the vehicle and slow down the same speed as the vehicle, then you will survive.
The reason I mention this, is I have seen polishing effects from slight movement on weaver/picatinny scope mounts. The scope appears tight, but when you remove it after use, the contact points are shiny like the mount has be shifting back and forth a fractional amount every shot. Not enough to loosen up, but enough to see the effects. And that is with factory specified torque.
That leads me to the idea that a lot of the scope failures people see is not caused by the scope, but caused by the mount. If the scope is heavy enough that the mounting ring does not have enough torque enough to restrain it. It may break where a smaller scope will be fine with the same installation.
Just because you think it’s solidly mounted, doesn’t mean that it isn’t moving.
The term I can think of that can describe it is ….. “scope slap”
That may explain why some people have no problem with a cheap scope on a magnum rifle, while other people have one after another of the same type scope fall apart with five or six shots.
When they buy a cheap scope, they will use cheap rings that is often purchased with the scope. When they spend a big chunk of money on an expensive scope, normally they will buy equal quality rings to mount it.
Some people mount a cheap scope with expensive rings. Either because they already have the rings, so why not use them, or the gun they have, requires custom rings that is needed to fit a scope to that rifle.
So, the one that uses good rings/mounts with a cheap scope, has no problem. The person that used the cheap mounts/rings with a cheap scope has it fall apart in 6 shots.
Basically, you may be able to cause a scope to break by not having the mounting bolts tight enough. Or having a weak flimsy mounting ring that will flex under the recoil jolt
Grind the recoil lugs off a set of rings and mounted them on a rifle with the scope in question. If the scope moves after several shots, then you don’t have the bolts tight enough. If you can’t tighten them enough to keep it from moving, then the rings are not strong enough to mount the scope you have. The bigger scope, the higher torque you will have to have.
If you don’t have it tight enough and rely on the recoil lug to stop it, you may be pounding the scope to death.
That would explain a lot of what i see on the web......
What do you people think?
