Leopoldo CDS

[ImBillT]

For the OP... Here is an article. I wish the CDS scopes were in this test... but the Mark series scopes were tested.

Tactical Scopes: Mechanical Performance Part 1

This is one of the last posts covering the detailed data collected over the past 4 months for an epi...

precisionrifleblog.com

And that didn’t even test repeatability or recoil. Box tests, live firing, and multi-scope bases have all revealed much more disturbing data regarding dialing a scope around.

 

[ImBillT]

By definition a coefficient is a constant.

Variables of the BC are cross sectional area, mass, drag coefficient, length and density. Velocity does not change the BC.

Bullet manufacturers have been providing G1 and G7 ballistic coefficients for bullets for reloaders- with no velocity factored in.

Not trying to hijack the thread...

Mathematically it is used as a constant, but a bullets BC is not usually the same under all circumstances. The BC is a comparison of the bullet’s drag function to the drag function of a standard projectile. The less like the standard projectile the bullet is, the less accurate the predictions made using the BC will be. The G1 standard projectile is shaped like a pistol bullet or WWI artillery shell. The G7 standard projectile is shaped like the 155gr Lapua Palma bullet. In order to get accurate predictions from ballistic calculators using a G1 BC with a G7 shaped bullet, we have to adjust the BC depending on the velocity because at some velocities the pointy bullet acts more like the G1 standard than at other velocities. The form factor tells us how closely the bullet matches the standard. If the G7 form factor is 1.0, then the G7 BC will not need to be adjusted at any velocity. The farther from 1.0 the more adjustment is needed. A form factor above 1.0 indicates that the bullet has more drag than the standard projectile shape would have if it were the same diameter and weight. A form factor below 1.0 indicates that the bullet has less drag than the standard projectile shape would have if it were the same diameter and weight. Most high BC bullets are close enough to the G7 standard that velocity adjustment is not important. When manufacturers were sticking to the G1, they were usually averaging all the G1 values over the velocity range they expected the bullet to be fired under. Because certain long range bullets were expected to experience a very wide range of velocities between the muzzle and the target, and even a wide range of target distances, Sierra would print three different averages over three different velocity ranges. It was quite helpful in figuring out where you should actually expect to dial at 300, 500, 600, 800, 900, and 1000 before the G7 became common.

 

[Mallardsx2]

Has anyone had any experience on using a CDS on an in-line .50 muzzleloader? I was thinking about switching to one for those potential 200 yards shots.

 

[maxx]

Has anyone had any experience on using a CDS on an in-line .50 muzzleloader? I was thinking about switching to one for those potential 200 yards shots.

There are multiples muzzy scopes out there with BDS reticles built in based on 100 grains of powder and 250 grain bullets. I get the dials if you are going to push out past 300 yards but under that just get one of the BDS scopes. They seem to work well.

 

[rmauch20]

I would try a swfa but hate the reticle...

I’ve had good luck with Leupold and m1’s...

I get that. It’s not perfect. I did add the after market zero stop.
My SWFA 3x9 was my first mil scope. After getting used to it, I prefer it now. I plan on picking up two more on the Black Friday sale and totally switching over to a mil dot reticle.

 

[tzone]

I would try a swfa but hate the reticle...

Same...too much going on with that sucker. A simple duplex would be fine.

 

[Muskeez]

In regards to the muzzleloader scopes, don't trust those little hash marks and rings on the BDC scopes either. Like someone said at the beginning, you have to shoot the distances and test everything. I've heard people say that they zeroed at 100 with their ML and BDC scope and now they are good at 150 and 200. HAHAHA, far from it, shoot at all of those distances and I'll bet the so called 150 mark actually hits at 140 or 160 and the 200 mark actually hits at 180 or 220. They could be even farther off than that, you won't know until you shoot all distances and hopefully that's not at a live animal.

 

[Trial153]

I been thinking of buying a Vx5 with the fire dot with CDS for my dad. I dont much about dialing scopes or aiming Systems but it seems like a user friendly system. for moderate ranges. That said the whole thing is foreign to me being a bowhunter

 

[ediggity]

I’m also considering going Leupold VX5 CDS for my new Tikka T3X in 6.5 CM... and I’m also not great with scopes, turning knobs, etc. I will be hunting between 100-300 yards so I’d hope I can go with a scope like that and have good groupings (and kill shots).

Then I read a few articles on fixed magnification scopes like the Leupold and Weaver and that seemed like a great fit.

It’s all very confusing.

I thought picking a rifle was the hard part... holy s**t. Scope shopping is the worst and driving me nuts

 

[manitou1]

Like stated above, you have to confirm and provide accurate data for Leupold to work with when making your custom CDS dials.
I returned from WY last week and had four big game kills with the VX5 hd CDS system. 621 yards, 454 yards, 379 yards, and 341 yards. Maybe I got lucky... or maybe the scope is still too new, but it worked well for my use.

 

[AggieOutlaw]

I’m also considering going Leupold VX5 CDS for my new Tikka T3X in 6.5 CM... and I’m also not great with scopes, turning knobs, etc. I will be hunting between 100-300 yards so I’d hope I can go with a scope like that and have good groupings (and kill shots).

Then I read a few articles on fixed magnification scopes like the Leupold and Weaver and that seemed like a great fit.

It’s all very confusing.

I thought picking a rifle was the hard part... holy s**t. Scope shopping is the worst and driving me nuts

Let folks here know your questions and we can help you down select scope options.

Generally, you don’t need an expensive high magnification scope for 300 yard shots. You can get by with a relatively inexpensive 2-7 or 3-9 power scope. A fixed scope offers little benefit over a good variable. They may be slightly better optically, but I doubt it.

The Tikka is a lightweight rifle. Don’t put a heavy scope on it. I recommend a Leupold VX3 or VX Freedom with a 1” tube that weighs 12 oz.

You can get those w a CDS or, better yet, sight in the 6.5cm at 260 yards with a 130gr bullet and you’ll be fine from 0-300 yard for any big game.

No need to complicate things

 

[44hunter45]

This should go without saying, but I'm that guy who has to say it anyway.

Lots on here about verifying your scope at actual distance, which is great. But if you only read an external ballistics chart off your ammo box or maybe Quickload for your handloads, you're not done yet. You have to test every possible variable. That means punching paper at actual distances, not just at 100 and then reading a chart for your other ranges. Some rifles shoot flatter than the chart, some not. If you don't know the real ballistics your rifle/load combo is shooting, fancy dials are just a guess.

 

[ediggity]

Thanks. Cool... sounds good. All makes sense as I've put in a ton of time reading and learning. I ended up getting a Leupold VX-3i 4.5-14x40mm with CDS last week. Will be using a DNZ one piece to mount it. I'm excited to get it sighted in and seeing how she shoots with diff ammo. Thanks again!