Home Forums Hunting & Shooting Hunting Optics Internal Scope Construction Toric, Zeiss, SWFA, NF, Leupold etc.

We blather all the time about our personal experiences that this scope never failed, that old Leupold friction adjust scopes hold zero, that SWFA scopes dial correctly, that NXS scopes can drive nails into a fence post be remounted and still hold zero but no one ever states what construction parameters are responsible for one rifle scope being more mechanically sound than another.

Why the hell does one stand up to more recoil, dial better, hold zero better than another? Does anyone know?

Good question jimmp. I'm looking forward to the replies.

Just peering into my SWFA scopes (objective end, with flashlight), I see the leaf spring screwed/pinned into place. On the 3-9x and 6x, there is one screw. On the 10x, I can see two screws. People claim that using a fastener to keep the leaf spring in place helps with zero retention, since the spring can't slip. If it slips, the erector tube moves and zero changes. Of course, the downside is more cost due to the extra machining, parts, and assembly time. Maybe a freckle more weight too?

On the Burris Fullfield, they are still using the big circular design that fits against the inner wall of the outer tube. I just looked at a new one the other day at the store. Supposedly this helps keep the spring in place, since the mounting area goes 360 degrees around the inner wall, instead of the typical narrow spring.

I've been told that Leupold used to have a leaf spring with barbs. The barbs were supposed to dig into the inner wall of the outer tube. The assembler would slip the leaf spring between the erector tube and outer tube. The spring tension and barbs would then hold the spring in place, without fasteners or glue. Maybe sandwiched between an inner ring. People have stated that the barbs could slip, allowing the spring to move, which can result in a change in zero.

I'm not sure if Leupold used this design, and if they did, if they still do. However, I've never observed any sort of fastener on the Leupold scopes I've looked into, but that doesn't mean that they don't do use something than can't be seen from the outside looking in.

My observations above are related to zero retention. In my simple brain, when I think about a scope "losing zero", I wonder about the leaf spring and how it is held into place. Maybe there is more to it than that, such as the amount of force pushing against erector, spring relaxation, etc.

For tracking, I don't know

I can only speak to swfa, and older leupolds, as that is what I have experience with. Swfa uses brass internal parts,and heavy duty erector springs. This allows precision, and longevity. As stated in other posts, my old leupolds had weak erector springs, and nylon internal parts. This caused poor return to zero, after a couple of hundred rounds. Night Force, uses brass internals,as I am sure some other good scope manufactures do. Those are the only 3 that I have torn apart ,or researched. Regardless of your choice,make sure the brands components are top notch.

you have to wonder why they use brass instead of steel? I do however get nylon...

I tore a Tasco apart years ago when somebody on a forum said they were junk because they had internal parts made of plastic. Like 90% of the crap posted by internet geniuses, they were wrong. No plastic parts to be found.

I tore my old leupold caps off and looked for myself. They were nylon.

Likely because brass is more resistant to moisture and corrosion than steel.

The Toric use the same system as the Night Force?

No idea, but I would like to know.

looks like no one really knows

I am waiting to hear from the toric reps in regards to this.

I suppose you all should know it depends... And that means what Mfr. and what model scope.

No, the scopes are supposed to be sealed from moisture intrusion so that isn't an issue any more, brass machines easier, is nice and stable, and has a lower coefficient of friction.

The problems with zero retention and tracking originate from the fundamental flaws that are inherent in the mechanical method used to adjust for elevation and windage. Modern riflescopes, put the reticle and the erector lenses in an inner tube. This tube is hinged at its rear end and is supported by the knobs near its front end. The knobs tilt the front of the tube up and down or left and right. A spring pushes the inner tube against the knobs and holds it in place.

The reason for using this method is that the reticle, even after adjustments, will appear at the center of field of view. If you only shift the reticle and keep the erector lenses centered, the reticle appears to move in the field of view like in vintage riflescopes. This is not very appealing to the shooter.

So, what is wrong with this mechanism? A lot actually. See the drawing below.

-Omid

from the other thread:






looks like Tract uses brass/ metal on the inside... not bad for the price point...

So did Tasco.

so does a FFP scope move the reticle out of the erector mechanism, hence FFP scopes are better to dial with and hold zero better? You also have to wonder what secret sauce NF uses in the SFP scopes.

FFP scope are better to range with the reticle because your dots/hashes are the same subtension at any magnification.

Hawke Optics are supposed to use coil erector springs and have etched reticles. Couldn't tell you about the rest...

Dan

The Tract Torics and Tekoas are etched, others are the conventional wire.