I keep reading that in order for scopes to track and dial well they need to be heavy - SWFA or Nightforce for example.

It seems to be taken as gospel, my question is - WHY???

I understand that a thicker aluminum tube may be more resistant to bending or bumping damage but dialing and tracking are a function of the mechanics of the scope.
If the internals are machined properly and have erector springs heavy enough to assure enough pressure on the erector tube to place and keep it in position how much could this possibly add to the weight of the scope? Even if the adjustment assembly were made slightly larger and the springs slightly larger how much weight could that add? Not more than another ounce or two I would think.

So why do we not have a lightweight scope like a Leupold that tracks as well as the old 1980's El Paso Weaver T series scopes? I doubt that there are any unexpired patents on the Micro-tract system - it seems to me that a Leupold with the Micro-tract system would be the best of all worlds.

drover

Good question and logic. I'd like to know also.

Maybe some use plastic parts inside while others use more metal pieces and lockdown screws instead of glue? Maybe bigger tube so internal lenses slightly larger and there’s 5-7 internal lenses sometimes... glass is fairly heavy.

More robust internal parts made from steel or brass instead of aluminum or plastic. Physically bigger parts since most dialing scopes are 30 or 34mm, a cylindrical object of 30mm is going to be stronger than a 1" all else being equal. Physics is physics, your nissan sentra might have a bunch of airbags but if you get run into by a 72 Ford LTD you're probably going to lose.

Those old T-6's weren't a lightweight, weighed in at 19 ozs.

I put one on my first Hunter Benchrest rifle, and had to send the barrel off for fluting to make weight.

you guys are funny, one word MARKETING. keep in mind the scopes you and I would buy aren't really what might be the best selling. In fact I bet they wouldn't be. lets establish first that a scope that is good at accurate adjustment also needs to cost more money, We should be able to agree on that. keep in mind that there is the cost to make the scope, distribute and market the scope, and finally retail sell the scope. you have 3 pieces to the pie that a product must have taken from it in the marketplace. All of those levels need to make money. I have someone in my family that took a company you could have heard about public. he told me you need 6:1 cost to retail value at the least and 10:1 is way better. That means a scope that costs $600 retail, it can't cost more than $100 for it to be made.

what is selling in the riflescope business? TACTICAL SCOPES at least ones that people are paying lots of money for. who is buying those scopes? its the guys who shoot 20 pound chassis rifles off fake barricades. These are your seal team 6 wannabees. Those scopes are marketed to the lifted black truck crowd. Basically its a crowd that thinks bigger is better. Why on early does anyone need a 34mm or even larger tubed scope? the fact is no one does. a decently made 30mm tube scope has enough adjustment to get you beyond 1 mile with any decent long range cartridge. Also many 34 mm scopes don't even have any extra adjustment internally over a 30mm. in fact one of the founders of tract told me its common for scope companys to use 1" internals and just stick them in a 30mm tube scope. bigger, beefier scopes are frankly what scope companies think people want. I would actually agree with their assessment. Higher powered scopes are being chosen, which have to be larger.

your average lifted truck, arm tatted, shamog wearing, millennial type guy who grew up playing call of duty isn't going to want a wimpy light weight scope on their gun. There are some lighter weight scopes that dial, but that depends on what you think is lightweight I suppose. I just picked up a ziess v4 and it tracks dead nuts. I am going to do a review on it soon and will post the results. Another one is huskemaw. Those scopes do track and they are half a pound lighter than nightforce. but neither of those scopes get you any street cred or IMO are selling all that well.

oh lastly I just see that you are from idaho. face it most people don't have access to public lands like you and I do. So ask yourself how much different is their typical shooting experience. are they hiking in the mountains? where is most of their shooting taking place? on a gun range 50 feet from their truck. of if they are hunting they drive a 4 wheeler up to the deer stand,

I buy them and use them on my hunting rifles. I do not own any rifles the weight you describe.

I fail to see how marketing or profit margins play into scope size, but I didn't study economics so it may be that.
What I know is that anything subject to stress is going to have to be beefier.
Seal team6 wannabes have nothing to do with weight I think. I don't think Linebackers weight 300lb due to marketing, they do because they perform better than a 155lb one would. Subject a 160lb soyboy to the stress of NFL attackers and it will crumble, no matter how well he does on flag football during the block parties with kids.

I'm sure they could make super rugged scopes out of extra light unobtainium, but wallets will also be extra light, and not too much market share would pay those prices.
.

if scope size isn't marketing then why are companies offering 34, 35 and even 40mm tube scopes? Some of which weigh in excess of 3 pounds. a 30mm nightforce NXS has been shot with a bullet, run over by a truck, used in real war situation and is 30 oz. but the hubble telescopes being sold are 3 + pounds and have 34-40mm main tubes. Look at burris XTR, 34 mm main tube but has less internal adjustment than a 30mm nightforce NXS. that scope is 34 mm for one reason and one reason only, marketing. yes the bigger is better mentality is real.

long range hunting scopes don't sell, believe me I hate it!! huskemaw, stupid name, great scopes but not many uses them, john burns sold a modded leupold years ago, G7 optics, have moved into other things besides long range hunting scopes. FFP scopes and these massive tactical scopes are what the high end market wants. we can get mad all day long but at the end of the day you or I will be in the same camp as the people that say why don't more companies offer a fixed 6x scope.

Send it!!!!

I am still waiting for a scope with a carbon fiber tube and plastic internal lenses. My eye glasses are extremely light and very scratch resistant so I know plastic lenses can be good.

3. 2. 1.

CONTACT

Carbon Fiber main tube is available.

There is so much misinformation in this thread it’s not even funny. A 34mm tube has the same internal adjustment as a 30mm tube? Maybe on a Chicom special, but not any reputable scope. 6-10x cost to retail? Again maybe chicom garbage. I have a Nightforce manufacturing cost list, and they are not makin a killing off their scopes.

Bottom line is, non-plastic internals weigh more, it is what it is.

I wonder how cc explains a $499 SWFA 3-9x HD?

I just bought one and it arrived today in fact!!! oh you just wait, I am waiting for the video equipment to show up and we are going to put that baby on a tall target and see what happens. if it's a joke like the 20x was, we are going to know it. I still don't like the reticle on the lowest power. but didn't get a chance to check it in low light, but I am thinking I will be disappointed. It really needs to be bumped up to 5x or so for best visibility.

That’s going to be a highly anticipated video. Get after it!

Just don’t forget these!

You guys are funny. All 225 pounds of me can hang off the thing, yes I checked. What do I gotta do break out the mig welder? It’s ok this time the video is going to be inside the scope, You will know it if there is a problem

Amazing thread, and not because of actual info.

In fact, JFC, if you'll excuse the term (which might means Just For Consideration, but doesn't).

It's not a joke. To start, it has HD glass and doesn't have a 2.1 exit pupil. Better turrets than Classics too.
I was able to see the reticle at 5x 30mins before sunrise 2 weeks ago, in a moonless night leading to a foggy day. That was in Texas piney woods.
I would have been able to make a killing shot at 200yds (longest clear cut) way before legal time.

It may suck, but I don't know, cause I didn't C-clamp and tested it. I put it on a gun a shot it at different distances, which is what I bought for... the SWFA marketing got me

Just keep giving more rope, don't rain on the party

What I don't understand is why a reliable dialing scope needs an extra half pound of internals. Or more.

I could see 3-4 ounces, but there ain't a lot of room for extra pig iron inside most rifle scopes.

How many dialing scopes have you used extensively, say for years of up and down?

Also, did not know "pig iron" was used inside 21st-century scopes.

You’re no launcher....you’re no launcher at all!

Maybe put your head in one of those C clamps and screw it down tight..... the SS 3x9 will perform just fine.

Don't believe weight has anything to do with it. Accuracy, reliability and long term repeatability on the other hand requires detail and quality, and even then I would tend to think that a manufacturer would make every attempt to keep weight within reason and as light as possible... Nightforce scopes being mentioned, if you compare their cheapest $1k scope to their most expensive $4.5k scope of comparable sizes there is only about a 30% increase in weight.28.5 oz. to 41 oz. If I had to rely on a scope and cost was no factor I'd tend to go with a 30% weight increase for that added reliability. Hell, I like heavier rifles anyway...


Phil

John, you're being kind of literal......

I don't "extensively" use any my dialing scopes, and not sure what you mean by up and down. I change loads and adjust for wind left and right often enough, too

You may not be aware but most of the various steels start out with pig iron. Can you tell us what materials are used in 20 oz + dialing rifle scopes to make them that heavy?

Thicker tubes, not just exterior but erector, and other metal inner parts--instead of the synthetics used in lighter scopes.

Will add that close to 20 years ago a well-known European optics firm introduced a lower-priced, but still optically very good, riflescope. They sent about a dozen to various gun writers, after engraving the writers' names on the scopes. I may not have been the only one to thoroughly test one, but suspect I was, putting it on an accurate .375 H&H and starting to shoot at a 100-yard target. The scope only lasted around 20 rounds before the groups opened WAY up.

I contacted the firm's U.S. public relations person and told about my results. In the meantime a well-known gunsmith friend had encountered a similar problem. As a result the company asked for the problem scopes back, and found a consistent problem with a synthetic inner part. They pulled all the scopes off the market--or at least all they could, as some had already been sold to individuals. The part was changed to metal and the scope went on to become very popular--but it was a simple set-and-forget scope, NOT a dialing scope that would be subject to a lot of up-and-down.

Since the trend toward dialing scopes started I have been sent quite a few for testing, including some that were relatively light. One of these gave up the ghost after a few ground-squirrel shoots on a .17 HMR, refusing to adjust consistently. Obviously recoil didn't have much to do with it. Instead the adjustments simply wore out.

Naw, there's no reason to make the innards of dialing scopes out of heavier, tougher stuff.

Someone should do titanium innards for these boat anchors.

It's the difference of a half pound that makes me curious. The glass lenses are probably the heaviest part of the sub-assemblies in a scope, the tube being the second heaviest. Even doubling the thickness of a scope tube would "only" add a few more ounces. The erector assembly is obviously made of very small parts, changing them from synthetic to metal doesn't seem to account for the significant increase in weight.

Maybe they quadruple the thickness of the tube.

I wonder what a scope would cost if the metal parts were made of titanium......

Ha! Beat me to it!

Is titanium a good material for parts that rub against each other? I'm not so sure about that.

good point.

Huskemaw - now with plow steel!

It does sound like a brand of farm tractor.

"See the new Huskemaw 4200 with more diesel power at your local authorized dealer."

Part of the weight increase can be attributed to larger diameter tubes, typically 30mm instead of 1 inch. Thicker and more of it.

I have replaced a couple of 1 inch scopes with 30mms, and noticed if the objective is kept near the same, the actual feel doesn't seem to be as affected as I first thought it may be.

"Now through Sunday, mention the infamous "diesel cowboy" sent ya for an extra 1/3 MOA discount"

Interesting idea on titanium. The downside is that titanium costs far more than stainless steel per pound.. While titanium weighs only a little over half as much as steel, the price difference might make the cost of SWFA scopes about as much as Swarovskis.

Oh heck my titanium long handled spork cost all of $8

Nightforce uses a titanium leaf spring. You guys are forgetting price point here. A lightweight dialing hunting scope that would sell like crap. I would buy it. You would buy it but who else

It would be junk, I wouldn't buy it. I want my scopes to be bullet proof.

So, just to address a couple of the questions that have been asked with relevant information, rather than speculation.

"Why do they need 34mm tubes (or even bigger)". The reason that tube diameters are bigger is because a larger tube is stronger. The market asked for a scope that could withstand the rigors of combat and extreme hunting while still being ultra-reliable. Take a fall with a 1" scope and the same fall with a 34mm scope and I can guarantee that the 34mm scope will withstand the impact better. Of course everything has a limit, so please don't wax eloquent about how you fell down the side of a mountain and your Nightforce was trashed so I obviously don't know what I am talking about. Physics is physics. Something that is bigger in diameter can withstand bending and crushing stresses better than something that is smaller in diameter. Add extra thickness to it and it is even better.
So, now that we have established why they make them bigger in diameter and thicker (therefore adding weight), you now also need to add extra glass diameter and bigger internals, also adding weight. And those internals have to be able to withstand the extra abuse that may be placed on them now that the tube is more robust.
All-in-all it isn't hard to see how an extra 10-15 oz can get added between a "standard" scope and a "premium" scope.

You certainly have a good point, and I think the obvious answer is that nobody posting here actually knows for sure.

Even if the tube thickness was quadrupled, that'd only mean an ounce or two. Aluminum isn't that heavy; when I'm machining something to remove weight, I have to remove a LOT of aluminum to make much difference.

More/thicker glass maybe? That's got to be the heaviest part of the scope.

Is Mule Deer suggesting lighter scopes have plastic internals?

One comment on SWFA scopes using brass internals - brass is cheap to machine, so parts can be turned out pretty fast and don't have to be sent for anodizing. Downside is that it's heavy. Material choice does make a difference in both performance and cost, and the cost includes machining time as well as basic material cost. The SWFA scopes could definitely be made lighter and just as good or better, but would cost more.

Scope manufacturers are able to take the easy way out and just make it heavier everywhere because the customers don't care. They will eat up everything which is spoon fed to them. It is entirely possible a manufacturer could make a relatively lightweight, durable scope with super-reliable adjustments but there is no compelling need for them to do so when they can just make a very heavy scope, put a lot of dots in it, price it high, and they'll sell a bunch. GD

This question has had a longer life than I would have thought, lots of interesting responses but no real answer yet.

I should have been a bit more specific in scope specifications - I was thinking of a Hunting Scope, 1 inch tube, in a common magnification range such as 3-9x40, like a Leupold VX-2 or Bushnell 3200, Burris FF, etc, not asking it to be a dialing scope but simply a scope that tracks and responds to adjustments properly. So using that is a basis for the question I still am not seeing an answer.

'I understand that a thicker aluminum tube may be more resistant to bending or bumping damage but dialing and tracking are a function of the mechanics of the scope.
If the internals are machined properly and have erector springs heavy enough to assure enough pressure on the erector tube to place and keep it in position how much could this possibly add to the weight of the scope? Even if the adjustment assembly were made slightly larger and the springs slightly larger how much weight could that add? Not more than another ounce or two I would think."


drover

who asked for the 34mm tube and heavier duty operation? these guys found 30mm to work just fine. https://www.sportsmanguncentre.co.uk/blog/2011/03/31/the-nightforce-bullet-hole-scope/



here is a link to another https://vimeo.com/109698139


I don't buy the 34mm tube being heavier duty, and if it is its not enough to matter. These guys are pounding nails, throwing the scopes around, shooting them. taking bullet holes in them. 34mm tubes are for lifted trucks and 22" dub wheels.

34 mm tube scopes are like this truck. all show,

I’m not sure what a “dialing” scope is, but a scope is either designed to work correctly or it is not.

that is jordan's truck BTW






























































just kidding

I wonder if there are any Cummins that are all show....

For the life of me I don't understand why folks don't realize this. I also don't understand why folks will settle for spending their hard earned money on scopes that wont reliably work like a scope is suppose to

I know one for sure that is and thats been proven multiple times

In the case of the March scopes with 56mm objective, the reason the main tubes are 34mm in diameter is simply that the thickness of the tube wall goes from 2mm to 4mm. This makes these high magnification scopes very solid. It works well for me as my March-X 5-50X56 sitting on top of my F-TR rifle has aimed around 20,000 rounds of match ammo over the last 5.5 years, without flinching. And it's still lighter than my NF NXS 12-42X56.

You have just given a bonofied reason for a scope of that design. If there is a real reason a scope needs to be a certain way to accomplish something specific. Plenty fine by me. I am sure you would agree a lot of other optics aren’t selected like that

You may be right, and I certainly do not pretend to know every other scope that exists. When you look at the specs of a scope from a fairly reputable maker, you can figure out why they chose 34 instead of 30 or even 1inch. The NF ATACR specifies an elevation range of 100MOA, in their 34mm tube, which leads me to believe that it has a 2mm thich tube wall an thus uses the additional 4mm of ID in the tube for the additional range.

I have seen 40mm tubes, I just have not looked at the specs for them. And yes, there are scopes that are really porky. Just looking at the specs of the NF ATACR 7-35X56, it's a half pound, 8 ounces, heavier than my March-X 5-50X56 and has a thinner tube wall. They both sport ED glass, so why the huge difference in weight?

I've made my living with steel for 48 years and have no idea what "pig iron" is. I suspect it is a slang term.

Even our CM rifles have pig iron in them--AKA carbon steel. It's a common term for the pellets that most steel and it's alloys start with.

Internals, internals, internals.

Wrong.

"Pig iron is an intermediate product of the iron industry, also known as crude iron, which is obtained by smelting iron ore in a blast furnace. Pig iron has a very high carbon content, typically 3.8–4.7%,[1] along with silica and other constituents of dross, which makes it very brittle and not useful directly as a material except for limited applications."

Bonofied? Sonny-approved?

Pretty sure I read somewhere that it's not. I believe it was in reference to its use in rifle actions.

Don't hold me to that, as I'm Pretty Old.

Made in Poland.

Titanium galls.

Yeah, I figured the cowboy didn't know Latin; pig Latin or pig iron; take you pig, I mean pick. Then again, maybe he was just playing.

Or maybe he was talking about Fibonacci numbers.

I think he was trying to say "bona fides".

Sigh......

"Pig iron is used for making steel and pure iron units. It has very high carbon content along with silica and another constituent of dross. Pig iron made from smelting iron inducts with the high amount of carbon for further processing steps."

"The name 'pig iron' originated in the early days of iron-ore reduction when the total output of the blast furnace was sand cast into 'pigs' —a mass of iron roughly resembling the shape of a reclining pig."

"Chromoly steel is actually alloy steel grade 4130. The “30” at the end of the grade number designates that it has approximately 0.30% carbon by weight. The added chromium and molybdenum help to give the steel different properties from its mild steel counterpart, AISI 1030, even though they have the same percentage of carbon."



Now, the subject of this thread is about heavy scopes that dial reliably.

There's the problem with dumbed-down blanket statements like that - it's true about one condition, but not everything, but people repeat stuff like that without bothering to learn the truth. It's no more accurate than "aluminum galls" or "stainless galls" which are also true in certain conditions.

Most grades of titanium can tend to gall against titanium. But, it works very well without galling against steel and other metals. It can potentially be a very good material for scope internals, but the material itself is expensive, and it's even more expensive to machine parts from it. It'd work, but would people pay for it? Some would, for sure, as we see from other titanium parts in the gun industry.

put titanium internals in a 34mm tube lol then c clamp to the light pole .

Did your fat ass use an indicator to verify it didn't move, tubby?

The increase in cost of Ti internals is negligible when compared to the overall price of a quality scope. You're talking maybe $5 for Ti compared to $0.50-$1.00 for brass or aluminum stock material to machine the internal parts. Yes, 5-10x the cost but still only $4 added overall.

As to the machining of Ti, it used to be an issue years ago but with modern 5 axis cnc, better programming, high speed spindles, new coatings on tooling etc. etc. Ti is being machined on a regular basis all over the world with little issues.

I'm sure the manufacturers have already looked at Ti and skipped it for reasons than cost or some inferred complications of machining.

Your use of the term pig Iron was and is incorrect

I machine Ti myself and am well familiar with it, and also have an engineering career that deals with manufacturing and am familiar with that side of things too. I would not make that assumption in your last statement. Ti can absolutely be used for scope internals if people wanted to pay for it, but it would definitely increase the cost. You don't think places like SWFA use brass internals because it's the best material available, do you? They use it because it's cheap to manufacture their scope internals that way and they aren't trying to build a light weight scope.

One example of Ti not galling in regular use is suppressor threads, like on my Gemtech .22 LR suppressor which has a Titanium insert for the barrel mating threads. Ti is used there because it is resistant to wear against steel for repeated installations and removals, and it definitely does not gall in that application. I've used it for the same purpose on my own suppressor builds with great results. The galling is really only an issue with Ti on Ti, and even that is not as bad as a lot of 300-series stainless steels, and can be alleviated by lubricating the surfaces.

You should try to contact Nightforce and speak to one their design engineers. If you can get through to one, you'll get the answers you are seeking.

Well, there's also the guts, pig or otherwise, that secures the lenses in place, no?

There's a new sheriff in town and it's obvious you're going to have to up your scope testing game.

Once you've solved the issue of your titanium galling on your pig iron and have an erector assembly capable of precise adjustments, now, and over time, you still have to hang it and mount the lenses so they stay where you want them, under repeated recoil and other outside impacts. That's going to require a certain amount of material to reliably hold screws or other fasteners and maybe adhesives that will hold up under the same forces and that don't break down and futz things up by running or depositing vapor where you don't want it, or letting little crumbs loose to gum up the works. At some point, clever engineering and exotic materials run you up against the unyielding wall of cost vs benefit and if you want people to actually buy your scope, not just marvel at it, you might just have to opt for heavy over tricky. Even very expensive scopes that have proven to be reliable are all pretty beefy, and I doubt it's because they skimped on materials or engineering, but rather because it's what's required. They certainly aren't concerned much with keeping the price down.

As buyers and users, we can keep the weight down by opting for simple designs sans giant turrets, side focus, illumination, and big honkin' objectives, most of which are of limited usefulness in putting meat in the freezer, which, if I can remember back that far, seemed to be what the OP was looking for. Even the simple models from outfits like S&B are pretty heavy I've noticed, which should tell us something.

I wasn't thinking of the galling issue, more along the lines of thermal expansion/contraction due to temp changes in different materials. I don't know just guessing.

So what would the difference in time/cost be to machine Ti vs brass? The materials cost, as I said, in percentage terms is high, but actual cost is only a few dollars more per unit of material for each part. I just don't see how the labor is going to be so much more working with Ti that a manufacturer is going to avoid using it over brass to meet a price point for customers when we're talking maybe a $20 increase(if that) for a scope that comes in at less wt.?.. especially in today's world of gram counting mountain hunters? Maybe not enough pressure yet from customers to get manufacturers building lt. wt. scopes that function properly as do the NF and SWFA ss's?

Wrapped around the axle about galling? How About brass deforming. Brass isn’t designed to be a wear metal. I would rather worry about galling than the softness of brass even if the weight was the same

Dumb^^^^^Ass

It's ok, we'll just carry on.

Besides, I'm still voting for titanium......

Brass is used a lot as a wear metal ...... not much on the park playground but still

Tested like no other. ...

Thrust washers (bearings) or bushings aren't a thing?

I worked in iron ore mining for few years. Pig iron is the first step in iron ore smelting. It's not used as a product for building anything, but rather as a feed stock for further processing.

Exactly

I'm a maintenance mechanic at this lime plant and the entire kiln and contents (400 tons + or -) rotate 24/7/365 exclusively on brass bearings.
I think brass could handle rifle scope internals just fine.

The real question is are your c-clamps made in China ?

Does that thing turn the limes into juice?






























.



Disclaimer, I did some time at a pulp mill's kiln...

Sorry I killed this thread.

It's the 1st ingredient in Brass Monkey.

LMAO. It kinda does!

Sure those Kiln bearings arent bronze?

You may be correct, good catch.

Are they bearings or bushings?

A bushing is a bearing.

Pasted:
Bushings, also called sleeve bearings, are just one specific type of bearings. They are made to slide over rods to provide an extremely low-friction motion. They are excellent for shock absorption and work to minimize energy usage, noise, and wear. Bushings are widely used for heavy-duty wheels that require high load-bearing tolerances.
And:
A bushing is a thin tube or sleeve that allows relative motion by sliding (our type), as compared to rolling. ... Thus, a bushing is a bearing, but a bearing is not necessarily a bushing type. A bearing is the general term for something that allows relative motion between two components, surfaces, etc.
From:

https://www.ggbearings.com/en/bearings

To answer your question, they are bushing type bearings.

The entertainment value is off the charts....

Dialing scopes typically have LOTS of erector assembly movement. You can't get 120 MOA of movement in a 1" or 30mm tube. The specialty ELR scopes have 40mm tubes! The more room inside the scope, the more the scope can move. The parts (lots of them are in fact copper alloys) are bigger and heavier. ED glass is VERY dense, bigger internal lenses= heavy. Thicker, stronger main tubes to keep the scope with all its inherent weight from deforming... It's a product of being big and strong.

The iron ore mine I worked at had the largest kiln in north America that we used to cure/ harden green iron ore pellets. The bearings where also bronze as far as I remember.

Pulp mill kiln, 400' x 13" ran on steel roller bearings, thrust? Lime mud to quicklime that dropped into green liquor from, the recovery furnace to make white liquor that breaks down the chips. I can't remember chit but it was quite a process! NG fired. One man show. A fair amount of dialing required.

A 30mm SWFA 6x has 140 MOA of adjustment.

March has released a 5-42X56 FFP with 140MOA of elevation. It's 34mm tube has the same ID as a 30mm tube, it's the thickness of the tube wall (4mm versus regular 2mm) that accounts for the 34mm OD of the tube. The reason for the thicker wall is the scope is designed to be used, a lot, by all sorts of guns.

Also, the business about heavier glass and all, one needs to remember that in a variable riflescope, there's going to be a dozen or more glass elements and lenses and of those, only one or two will be ED glass.

My current March-X 5-50X56 has ED glass and a thick-wall 34mm tube and yet weighs a half pound less than my Nightforce NXS 12-42X56 which has a 30mm tube and does not have ED glass.

There's more to a scope's weight than glass and aluminum.