Erector tube stress.

[NORZ]

Well, A friend of mine broke the erector tube in a high-end scope mounted on his rifle, a 300 Lapua Mag. The scope was about 10 years old and has had an unknown number of recoil cycles subdued.

A scope failing after a long term of use and abuse didn't ring any bells, but he has had the scope mounted with a 25 or 30 MOA canted base on this rifle. He´s gone through 2 barrels,about 2500+ rounds) on the 300 Lapua and the rifle zeroed at 700-1000 meters and only shoots over 1000+ meters and dials it in centered every time at any range.

Anyways...........................To make a long story short. I´m wandering, whether having the scope always dialed up on the canted base to reach over 1000 meters, will cause the erector tube and internals associated with to be subdued to higher or more serious forces than it will handle?

Any thoughts on this?

 

[NORZ]

I dont want sound frantic.... but, does anyone have any input on this?

 

[butchlambert]

I think that he is lucky that it lasted that long.
Butch

 

[1000yardstare]

The African hunters are happy if a scope lasts through one safari with their large cartridges.

On the Canadian Army ranges, I have seen scopes destroyed in three shots with the .338 Lapua, 50BMG and the like.

A member of my local gun club bought a sporter weight Sako in .338 Lapua and had the stock crack in very short order. He went after Sako for warranty and the reply was something like 'If you are dumb enough to buy such a rifle, you probably never read the fine print in the warranty that said LIMITED WARRANTY ON THE STOCK'.

I think a healthy dose of reality is needed for those who wish to dislocate their shoulders in the name of 'fun'.

 

[watercam]

That being said,as it should be), if he has 25 moa of slope in the bases I'll bet he doesn't have much elevation dialed on his scope. He should need no more elevation than my 6mm 1000 yd. load and I'm at 30 min. out of 45 min. available,with a 1' tube, I'd bet he has 30mm or better). If anything it's a testament to that scope for lasting so long. My shoulder would have given out long before.

 

[fdshuster]

And I personally know people who have torn the retinas from their eyeballs while shooting the 'big' guns, so have fun: not for me.

 

[NORZ]

Thanks for the input guys. That particular gun is closer to a rail-gun in my opinion. At least, it weighs in at 11 kilos. And the scope is a Nightforce benchrest model.

 

[jackieschmidt]

I agree with Lynn, the big Lapua is really not that more abusive than a big Weatherby, or an Ultramag, for that matter.

As has been said, the erector tube is held inplace inside the scope by nothing more than a pivot joint on one end,,I call this a 'gimble mount'), and one or more springs that hold the other end against the turret abutments.

Every time the rifle fires, the erector tube is jammed against one end of the gimble joint. Sooner, or later, this joint will become compromised.

How quickly this happens depends on how robust the joint is. Some, such as found in short range Benchrest Scopes, are rather light in cross section, and will not hold up under such abuse.

The erector tube its self has lenses either glued into place, or held in place by a nut and thread. Common sense dictates that when subjected to large amounts of recoil, these can also become compromised.

I see nothing in the way your scope is mounted that would contribute to the failure. I tend to agree with Butch Lambert, you are darned lucky it lasted that long...........jackie