Long range hunting scope.

[lightwind]

You seem to be of the impression that an infinite amount of light can be focused down
to any size and passed through a lens with no additional loss. Not my understanding of
light and optics. But I am not claiming it's a large gain by any means, I did say a little more light. And I really don't know if some of the 30mm tubes have any larger erector
lens or not. They may have. But my swaro 3x12 30mm has a pathetic 39 moa of total
travel. Nightforce can squeeze 100 out of the same tube. Looking through the scopes
is a totally different animal. One is an enhanced bright picture and the other just another
scope. Like you said lots of difference in glass and coatings. Even my USO's are not better
than the Swaro in glass. I don't doubt a Zeiss would be any different. Making the erector
shorter and ffp vs sfp would also play into how much elevation can be delivered. With a
shorter erector the mechanics of holding it in place become more of a challenge and the
physics in the optical design would be different as well.
It would be fun to take a class from a scope engineer on all this stuff wouldn't it. I like
the equipment as much as I do using it I think.
( microscopes are a great example of how badly light is transmitted through a small lens,
look at the 1000x lens and without a bulb right behind it you see only grey. Much different
in design and application so I am not sure if it's apples to apples)

Loner:

Great topic that may or may not be of interest to the group. Let me address the issue of focusing the light through a small lens. The issue is the amount of light that falls on the surface of the objective (and in particular, the amount of nearly parallel light that falls on it becaus that is what is focused). If you look at the amount of light entering a telescope it is limited by the size of the objective lens. That is in the area of 20 mm - 75 mm. That light is then focused onto the focal plane of the first erector lens. So, you are gathering light from the surface area of the objective.

In the case of the microscope you are gathering light with an objective lense generally smaller than 1mm. Area goes as the square of the diameter (or radius) so the surface ratio is huge going from a typical hunting scope to a microscope. That is the reason you need a bright light for transmission microscopy. It is because the surface through which the light enters the lens system is greatly constricted.

This is also the reason that the amount of light transmitted through a telescopic sight goes up with the diameter of the objective lens. Limit the size of the objective and you need more light.

 

[etisll40]

Great conversation men, I'm getting good ideas. I was leaning toward the Zeiss and Swarovski mentioned and now I'm going to go see them. The BSA sounded interesting too. The Swarovski is really light which will reduce by at least a pound+ which matters to me. But glass clarity is #1. My typical distance for my 7stw will probably be 300-700 or so, I see that as my sweet spot. Thanks for chiming in. Deer season starts here on Saturday so for now I'll keep the Leupold on it for now, but I do see a lighter scope very soon. Lots more shooting ahead...

Tell me more if you think of anything.

Thanks, Ed

 

[lightwind]

etisll40: Just be clear that the mention of the BSA was to point out that, at least, one person can shoot well with some of the worst optics made. While I don't doubt that the person made those shots it was not due to the scope. BSA is, generally, an entry level optic that has a reputation for lack of reliability and poor optics. However, I am going to buy one to be able to compare it with some of the better scopes. When I see a scope for around $100 that has the same external characteristics (zoom range and turret clicks) as a $1000 scope I am a bit suspicious. Never having purchased one I have not been able to comment on it or Barska (another of the noted bottom feeders). I will stick with the comment that everything I have heard about BSA and Barska (as well as Dark Ops "Countersniper") is that you should expect low performance for low price (or in the case of Countersniper - high price). As usual, your mileage will vary and I welcome anyone to chime in with why a $150 scope is as good as a $1500 scope. I like these discussions because they bring out some very interesting responses. I'm ordering my bottom end scope tonight.

 

[joseph]

As for my 6-24x50 MOA FFP PST the reticle is about 8 inches thick at 1,000 yds. and the fine reticle of the 8-32x50mm BSA is about 2 inches thick at 1,000 yds. I believe that trying to hold a 8 inch think reticle in the center of the bull at 1,000 yds. is much harder than holding a 2 inch thick reticle in the center of the same bull at 1,000 yds.

There was almost no wind when I shot those groups AND I also shoot as fast as I can to keep the five shots in the same conditions.

joseph

PS: Of coarse I am not going to brag about my group sizes when there was significant wind.

First picture is a .243 compared to the 6mm Norma BR. with Berger 105 VLDs that I shot these groups.
Second picture is one of my best 200 yd. groups.
Third picture is a 8-80x56mm March scope with fine reticle looking at 1,000 yds. at 80 power. ( wish it was my scope ).

 

[Loner]

Eight inches fits in the 10 ring just right( 10"). Should neither help not hurt your aiming
ability. I usually have to crank down to 16X or so to get a clear picture with mirage
and that puts you at about five inches, perfect on an x ring yes? (f class targets)

Looking at the vortex reticle it subtends .18 moa I assume at 6x. How does that grow to
8 inches at 24x? The math puts it more at 3 1/2. Is there something I am missing?

 

[lightwind]

Eight inches fits in the 10 ring just right( 10"). Should neither help not hurt your aiming
ability. I usually have to crank down to 16X or so to get a clear picture with mirage
and that puts you at about five inches, perfect on an x ring yes? (f class targets)

Looking at the vortex reticle it subtends .18 moa I assume at 6x. How does that grow to
8 inches at 24x? The math puts it more at 3 1/2. Is there something I am missing?

OK, let me see if I have this right. The Vortex Viper PST MOA that I have is a FFP (First Focal Plane) reticle. What that means is that the reticle expands with the sight picture so that one moa on the reticle always covers 1 moa on the target. I am as confused as loner here as to how the .18 moa can expand to 8" at 1000 yards. From my view through my scope and my understanding of a FFP scope it should subtend .18 moa at every magnification. That means that at 1000 yards it would still subtend .18 moa which is about 1.05 inch/100 yds * 10 (100 yds/1000 yds) * .18 = approximately 1.89". Looking through my scope at 100, 200 and 400 I see it expanding in proportion to about 1.05" * .18 per 100. So, with what I can range outside that is what I am seeing. How does approximately 2" expand to 8"? I don't get the 3.5" loner gets (I get the 1.89"), and I certainly don't get 8". Loner seems to be much closer to the mark. Please explain the 8". Do you have a defective Vortex Viper PST?

 

[joseph]

Eight inches fits in the 10 ring just right( 10"). Should neither help not hurt your aiming
ability. I usually have to crank down to 16X or so to get a clear picture with mirage
and that puts you at about five inches, perfect on an x ring yes? (f class targets)

Looking at the vortex reticle it subtends .18 moa I assume at 6x. How does that grow to
8 inches at 24x? The math puts it more at 3 1/2. Is there something I am missing?

I am still new to long range competition and I still have a lot to learn. As for cranking down the power to make the reticle half the size this does not work with a First Focal Plane scope like the PST FFP. The reticle stays in proportion to the size of the target no matter what power you crank it to.

I'm used to trying to hold inside a bullet hole at 100 & 200 yds. and am not comfortable holding such thick reticles at long ranges.

joseph

PS: I may have gotten my measurements screwed up. I have be going by memory and thought that the reticule was .8 thick. I guess it must my bad.

 

[wrongside]

DANG !! I am sorry for not knowing the internals of a rifle scope. Also for my inaccurite statement about tube size and light. To the gentleman with the knowledge of scopes i am sorry for putting you through all this. You have had to answer to a lot of people and I hope they have learned as much as I have. Thank you for sharing! ps. Maybe I should keep my fingers off the keyboard till I know what I an talking about! This might be a record for replies for an 8 month old post.

 

[Loner]

Joseph I guess we are saying the same thing but from different ends. Yes the target and
reticle stay in proportion in ffp. For some reason I am brain locked on the .18 moa. I guess it means .18"@ 100 yards and 1.8 inches at 1000? I can't figure out how it
grows to 8 inches? Not trying to be a pest mind you.

 

[joseph]

Joseph I guess we are saying the same thing but from different ends. Yes the target and
reticle stay in proportion in ffp. For some reason I am brain locked on the .18 moa. I guess it means .18"@ 100 yards and 1.8 inches at 1000? I can't figure out how it
grows to 8 inches? Not trying to be a pest mind you.

You are correct if I am reading specs correctly the reticle is .21 moa thick times 10 equals 2.10 moa at 1,000 yds.

For some reason I thought the measurement was .81 at 100 yds., but I guess I am all confused now. I do know one thing that the PST reticle is much thicker than the fine reticle in the BSA scope that I have on the rifle now.

I changed the PST to the BSA because of the much finer reticle which I think helped me shoot much smaller groups. By the way the BSA turrets are 1/8' clicks and do not seem to be very accurate. I was able to get the groups on the target, but scores were not very good only the group sizes.

joseph

PS: Maybe I have gotten confused about the reticle size since I've been laid up for a couple of months because someone tried to drive over me & my car. The helicopter ride was not fun.

joseph

 

[lightwind]

Joseph: Yes, you probably got the reticle measurement wrong. The Vortex subtension is given here:

http://www.vortexoptics.com/uploads/sub_viper-pst_624f1-moa_details.jpg

You can see that the thickness of the line is 0.18 moa. The distance between minor marks between 0 and 10 moa is only 2 moa so nothing quite lines up with the 0.8 moa you recalled.

However, you made up for any mistakes by showing the target through the March scope. It is no wonder that they are selling well. That is an amazing sight picture. Did you take it? It is outstanding.

 

[joseph]

Thanks for the measurements.

I did not take the picture with the March scope. It is an amazing scope.

joseph

 

[etisll40]

This is great info, but I have to study the FFP vs 2nd FP? I still don't have a clear understanding of this? I understand turrets and MOA but these different focal plans must have something I'm not getting. I do like that March scope MTR-3 reticle, that is a pretty good visual for me. I also have a Horus Vision Predator scope but haven't really got to use it at the distances I'm practicing at. Do the March scopes hold up to the jolt of a 7mm STW? Do they have a guarantee? Thanks, Ed

 

[Loner]

That 8-80x march is almost 5000.00. Something about Japans laws limit the written
warranty to 5 years. But I have seen guys post several times the owner of the company
will stand behind them for as long as he's around. There is a vid you can google of a
shooter down under with a 1000 yard bench gun. You can see the hits. Very amazing.
http://marchscopes.com.au/ click on the video on the top left.