24hourcampfire.com
24hourcampfire.com
Previous Thread
Next Thread
Print Thread
Hop To
Joined: Apr 2005
Posts: 666
S
Campfire Regular
OP Offline
Campfire Regular
S
Joined: Apr 2005
Posts: 666
I have a dumb questions. I see some scopes set up for specific caliber. .223, .308, etc. I assume the difference is the the hash lines in the scope are set up for the drop at specific ranges (but maybe not). So are they set up for a specific bullet and speed? If not I would think there is way too much variation to be useful, no?

As an obvious example in my .308 I could shot 110 gr pills really fast or 200 gr much slower. Clearly the trajectory is significantly different.


"Socialism produces bad music, bad art, social stagnation and really unhappy people", “I am a conservative, and you may not like that, but I am.” Frank Zappa 1986
BP-B2

Joined: Jul 2007
Posts: 24,589
Campfire Ranger
Offline
Campfire Ranger
Joined: Jul 2007
Posts: 24,589
It's more bullet weight (than actual bullet) and approximate velocity.

If you do some digging on the specific scope, you'll likely find info on the subtentions.

Here's a Leupold chart for some of their ballistics aiming systems:

https://cdnp.leupold.com/products/p...g-system-manual.pdf?mtime=20170626163401


[Linked Image from i.imgur.com]

WWP53D
Joined: Jul 2004
Posts: 6,629
S
Campfire Tracker
Offline
Campfire Tracker
S
Joined: Jul 2004
Posts: 6,629
Burris offers this which you use with their scopes and about any round you wish:

https://ballistics.burrisoptics.com/reticle-analysis#main

Nikon and probably others have similar apps.


'Four legs good, two legs baaaad."
----------------------------------------------
"Jimmy, some of it's magic,
Some of it's tragic,
But I had a good life all the way."
(Jimmy Buffett)

SotG
Joined: Jan 2009
Posts: 263
S
Campfire Member
Offline
Campfire Member
S
Joined: Jan 2009
Posts: 263
I bought a Primary Arms scope with the reticle set up for 7.62x39 123gr bullet. I put the scope on my Ruger Mini 30 shooting Winchester Power Points. I found the scope reticle very accurate out to 300yds once the rifle was zeroed per the instructions.

Joined: Nov 2013
Posts: 28,523
Campfire Ranger
Online Content
Campfire Ranger
Joined: Nov 2013
Posts: 28,523
I have a Hawke with a ".223/.308" reticle, but their app makes it easily usable with other stuff. Once you know the velocity and BC of a load and the spacing of the reticle marks, you can DIY it. The app just simplifies it. Still need to verify it by actually shooting if you want to be certain. In my case, since almost all shots are close, I'm starting to zero these scopes at 100 and keeping the marks in reserve. I'm much more likely to need to thread the needle in the puckerbrush than reach out long.


What fresh Hell is this?
IC B2

Joined: Apr 2005
Posts: 666
S
Campfire Regular
OP Offline
Campfire Regular
S
Joined: Apr 2005
Posts: 666
Interesting stuff. Thanks guys.


"Socialism produces bad music, bad art, social stagnation and really unhappy people", “I am a conservative, and you may not like that, but I am.” Frank Zappa 1986
Joined: Jun 2019
Posts: 76
D
Campfire Greenhorn
Offline
Campfire Greenhorn
D
Joined: Jun 2019
Posts: 76
Yes. The caliber specific reticle has been built upon a specified bullet grain, BC, & velocity. Additionally, if the scope is SFP, the holdover marks are only "true" at one magnification power, usually the highest, but not always. I have a couple of different scopes with a bullet drop compensating reticle and while they are not true to even 100 yard increments, most are pretty close. For instance, according to the Meopta ballistics calculator, with my BDC scope on my .270 shooting my 165 grain load, the third hash mark (nominally 300 yards) is actually 306 yards. That is assuming I have the scope set at the highest power. A quick range check showed it was fairly close, but if I change hunting loads, all that goes out the window.

Joined: Feb 2007
Posts: 7,884
J
Campfire Outfitter
Offline
Campfire Outfitter
J
Joined: Feb 2007
Posts: 7,884
The difference in trajectory among most common cartridges and bullet weights isn't as great as you'd think. I don't have any scopes with the caliber specific reticle, but several with multiple aiming points. If I zero any rifle in my safe at 100 yards the marks on the reticle are close enough at 200 yards, 300, 400, 500, etc. Especially for big game hunting where you have a 10-18" kill zone depending on the game animal. I shoot 6.5 CM, 308, 223, and 30-06.

With 308 the difference in drop between 150's, 165's and 180's at 500 yards is about 4". Comparing the flattest shooting load I have to the worst there is only about 10" difference all the way to 500 yards. Which would be significant if I were shooting 1" groups at 500 yards. When you consider that 5" groups at 500 yards is above average for hunting rifles the groups between the flattest shooting rifle I own and the worst would overlap with the same hold on my scope.

I've found the marks to be very close to accurate with my 30-06. With 308 my bullets may impact 2-3" lower with the same hold at those ranges. But that is still well within the kill zone of big game animals, and even if I do need to compensate a few inches out at 400-500 yards that is easier than 2-3 FEET with a standard reticle

Also consider this, it would be rare for a game animal to be at EXACTLY 200, 300, 400, or 500 yards. They will always be somewhere in between. If your range finder says 250 yards which aiming point do you use? You still have to choose one or the other and compensate somewhat.


Most people don't really want the truth.

They just want constant reassurance that what they believe is the truth.
Joined: Sep 2005
Posts: 1,716
S
Campfire Regular
Offline
Campfire Regular
S
Joined: Sep 2005
Posts: 1,716
A long time ago I put a 3-9 22 rimfire tree reticle scope system and used it on an AR shooting VLD-style bullets. Once the subtensions were known of each stadia point I simply calcd the zeros in 50-yd increments out to about 600 in std. conditions, and then recalcd the stadia zeros, i.e. if the 2nd and 3rd stadia are say 4.5 MOA and 7.5 MOA, and the 450 yd. zero is say 4.8, that's .3 MOA beyond 2nd stadia, since there are 3 MOA between them .3/3=1. So my 450 yd. dope is 2.1 stadia units. See how it works? By applying a system like this (including windage calcs) you can use just about any reticle for any trajectory.

Last edited by sscoyote; 03/24/20.
Joined: Jan 2001
Posts: 4,896
O
Campfire Tracker
Offline
Campfire Tracker
O
Joined: Jan 2001
Posts: 4,896
Originally Posted by SKane
It's more bullet weight (than actual bullet) and approximate velocity.

If you do some digging on the specific scope, you'll likely find info on the subtentions.

Here's a Leupold chart for some of their ballistics aiming systems:

https://cdnp.leupold.com/products/p...g-system-manual.pdf?mtime=20170626163401

I find that it's more a specific ballistic coefficient and velocity. But yeah, getting fast hits out to 4-500 yards is pretty straightforward once you read up on the reticle itself, figure out a zero that works, and confirm it on the range. I've had very good luck with the Ballistic FireDot as described in that PDF. What the manual says is the 300-yard aiming point is actually about 285, the 400 is about 370. Once I got it dialed in, little bit of holdover had me ringing a 6" gong at 400m (437 yards) pretty easily with a Tikka 30-06 shooting CMP ammo.

I haven't taken it beyond that.


Okie John

Last edited by okie john; 03/24/20.

Originally Posted by Brad
If Montana had a standing army, a 270 Win with Federal Blue Box 130's would be the standard issue.
IC B3

Joined: Apr 2005
Posts: 666
S
Campfire Regular
OP Offline
Campfire Regular
S
Joined: Apr 2005
Posts: 666
What a wealth of information and experience here on the Fire.

I am seriously thinking about the Meopta Optika6 2.5-15x44 SFP - .308 that Doug has on sale.

My most exotic scope to date is a Leupold VX-I 3x12 so it would be a major step up for me but this discussion has me thinking...

Thanks
dt


"Socialism produces bad music, bad art, social stagnation and really unhappy people", “I am a conservative, and you may not like that, but I am.” Frank Zappa 1986
Joined: Mar 2013
Posts: 3,584
Dre Online Content
Campfire Tracker
Online Content
Campfire Tracker
Joined: Mar 2013
Posts: 3,584
most of the scopes have specific bullet in mind. 223 with 55 FMJ at 3200, 308 with 1XX at XXXX,
I have a scope that came with a turret for 270 Win. with 130 at 3100. Read the fine print


All of them do something better than the 30-06, but none of them do everything as well.

Moderated by  RickBin 

Link Copied to Clipboard
YB23

Who's Online Now
696 members (160user, 117LBS, 10gaugemag, 12344mag, 01Foreman400, 76 invisible), 2,693 guests, and 1,309 robots.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums81
Topics1,187,688
Posts18,399,798
Members73,820
Most Online11,491
Jul 7th, 2023


 







Fish & Game Departments | Solunar Tables | Mission Statement | Privacy Policy | Contact Us | DMCA
Hunting | Fishing | Camping | Backpacking | Reloading | Campfire Forums | Gear Shop
Copyright © 2000-2024 24hourcampfire.com, Inc. All Rights Reserved.
Powered by UBB.threads™ PHP Forum Software 7.7.5
(Release build 20201027)
Responsive Width:

PHP: 7.3.33 Page Time: 0.328s Queries: 14 (0.004s) Memory: 0.8486 MB (Peak: 0.9423 MB) Data Comp: Zlib Server Time: 2024-03-28 22:42:22 UTC
Valid HTML 5 and Valid CSS