How to use a mil/mil scope-reticle, turrets and proper usage

[Formidilosus]

Thanks to this thread, I just zeroed my new rifle with my first mil scope easy peasy.
Bore sighted and fired 10 rounds.
Adjusted down 1 mil and right .7 mils using the “ruler” reticle.
Fired 3 more shots.

Not bad for the first 13 rounds through this barrel. Thanks for the how-to Form.

View attachment 794617

Yes sir. Easy peasy.

 

[Luked]

Marking for suture reference and reading.

 

[Idaho4x4Bronco]

Incredible read, thanks for posting this. As someone trying to learn dialing and understanding longer range shooting, this blows the confusing youtube videos away. Super appreciative Form.

 

[TxxAgg]

Tagged

 

[JoshOR]

Tagged Thanks!

 

[Alpha Echo]

Tikkas are easy, the ejection port bottom is center of bore. Just measure from center of scope to bottom of ejection port. Measure the red line.

View attachment 572509

Does bottom of port = center of bore hold for both T3 and T3x? I know the latter has a larger port but don't know in which direction.

 

[Formidilosus]

Does bottom of port = center of bore hold for both T3 and T3x? I know the latter has a larger port but don't know in which direction.

Yes.

 

[Mike Islander]

Make sure to loosen it enough that you can lift it off the splines, and make sure it doesn't click when you spin it to zero.

Just don't lift it all the way off. You can lose the tiny o-ring. SWFA Sent me a couple for free, but I wouldn't want this to happen in the field in wet weather

 

[Jhconnected]

Here is my quick drop. I have base 0, -.25 and -.5

It’s a useful tool but I’m not sure I shoot enough to trust myself to do the math in stressful flop sweat

 

[benconfused]

Curious for those with a Tikka 65prc using an oem barrel (mine is a roughtech), what's the avg muzzle vel you've been getting?

Diving into the mils concept now, after 1 round of 100 yards dialing. Starting to understand why mil is so beloved!

 

[mxgsfmdpx]

Curious for those with a Tikka 65prc using an oem barrel (mine is a roughtech), what's the avg muzzle vel you've been getting?

Diving into the mils concept now, after 1 round of 100 yards dialing. Starting to understand why mil is so beloved!

Get about 100 rounds down the barrel without cleaning it and don't fuss over "groups" or "velocity" until then.

What is your planned bullet and barrel length? We have a lot of data on 6.5 bullets with PRC's, just need some more info.

 

[benconfused]

Get about 100 rounds down the barrel without cleaning it and don't fuss over "groups" or "velocity" until then.

What is your planned bullet and barrel length? We have a lot of data on 6.5 bullets with PRC's, just need some more info.

Ahh good catch - I meant to add that info in.

Sticking with the 147 ELDM Hornady box, no reloads any time soon.

Stock barrel is 1:8, 24'. Don't have the stock muzzle break installed, not planning to change out a brand new barrel.

Maven rs1.2 with UM med rings, no rail.

Currently just under 50 rounds in.
-Black stickers were the walk-ins when dialing (again still grasping mil concept at the time and had not found this thread)
-Then the 2 on the left
-Final group for the day was 8-10 shots in the glob on the right
-Haven't made any additional adjustments just yet to pull it up and over into center.

 

[benconfused]

Now how do you take a zeroed rifle and use those turrets and that reticle?



You need a dope card or drop card that tells you how much to adjust for a given range.

We used to have to hang targets at every 100 yard line and walk our rounds into the target, note the required adjustments, and move to the next. With the advent of accurate ballistic solvers you no longer need to do that. You can use the ballistic program to "true" your data. If you know the real BC of the bullet you can true the velocity, or if you know the real muzzle velocity you can true the BC for an unknown bullet. In general chronographs are the weakest link and I would default to velocity calibration.

It's pretty easy to find accurate BC's for most bullets by selecting the bullets with "Litz" next to them in the ballistic program as those have been tested and verified by Applied Ballistics and Bryan Litz. While it is improving, manufacturers love to inflate their BC numbers.


The best way to true is to shoot a target as close to transonic speed as possible- as close to 1,340fps as you can. If you can't get that far, then do it as far as possible. If you input all the variables correctly scope height, BC, range, weather, etc. the outcome will be VERY accurate data out to the range that you trued.

For a target I use a piece of steel with a waterline across the middle (this one is set at 600). The goal is to get your rounds splitting the line. This allows you to true your velocity by manipulating the app.






You need a good app. There are quite a few good ones, but in this case I use Shooter on an IPhone. It's simple and provides good data. Regardless of what app you use, you follow the same general steps.

First build the rifle profile. Measure and input accurate data with regards to sigh height. I've named the gun, input the barrel twist, sight height, and set everything to mils, and 1/10th graduations-




Then I go to "Ammo" hit the "+" sign, and a screen pops up. Select "from bullet library" as I know the bullet I am using will be in there.





A "bullet diameter" screen pop up. Select your bullet diameter- for this one ".224".

Question to the group, that seems pertinent on this thread (imo)

1. Across all these apps, does "Sight Height" using a standard definition?
Google search defines as: "the vertical distance between the center of the rifle's bore and the center of the sight or scope" but that doesn't really mean it's standard because Google has a definition.

For example, I'm entering data into Maven's online calculator (for now).
Tikka T3 + UM Med + RS1.2 - my caliper is showing 1.85 based on the above definition.

 

[mxgsfmdpx]

Question to the group, that seems pertinent on this thread (imo)

1. Across all these apps, does "Sight Height" using a standard definition?
Google search defines as: "the vertical distance between the center of the rifle's bore and the center of the sight or scope" but that doesn't really mean it's standard because Google has a definition.

For example, I'm entering data into Maven's online calculator (for now).
Tikka T3 + UM Med + RS1.2 - my caliper is showing 1.85 based on the above definition.

Tikka T3X you measure from the bottom of the ejection port (center of bore) to the center of the reticle.

With Maven RS1.2 and UM lows use 1.65" in the apps and 1.8" with mediums.

 

[SteveAndTheCrigBoys]

Tikka T3X you measure from the bottom of the ejection port (center of bore) to the center of the reticle.

With Maven RS1.2 and UM lows use 1.65" in the apps and 1.8" with mediums.

Huh, I've had 1.5" in my calcs...RS1.2 in UM lows. Wonder how much error that could cause.

Tested it out...0.03 MIL difference at 1000 in my BH 77 TMK load per Revic.

Must be why I missed my first CBC shot

 

[mxgsfmdpx]

Huh, I've had 1.5" in my calcs...RS1.2 in UM lows. Wonder how much error that could cause.

Tested it out...0.03 MIL difference at 1000 in my BH 77 TMK load per Revic.

Must be why I missed my first CBC shot

Most use 1.5" in calcs because it's close to a lot of actual heights and is default for many Apps.

Makes nearly zero difference as you noticed haha.

 

[Alpha Echo]

Question to the group, that seems pertinent on this thread (imo)

1. Across all these apps, does "Sight Height" using a standard definition?
Google search defines as: "the vertical distance between the center of the rifle's bore and the center of the sight or scope" but that doesn't really mean it's standard because Google has a definition.

For example, I'm entering data into Maven's online calculator (for now).
Tikka T3 + UM Med + RS1.2 - my caliper is showing 1.85 based on the above definition.

I mean, not sure how an app could consider sight height as anything other than center of bore to center of scope. It's what I've always considered that input to be. FWIW I have seen it make quite a bit of difference in a ballistic solution at 500+ yards.

 

[Alpha Echo]

Tikka T3X you measure from the bottom of the ejection port (center of bore) to the center of the reticle.

With Maven RS1.2 and UM lows use 1.65" in the apps and 1.8" with mediums.

These measurements are super helpful, thanks for posting! These measurements should hold for all 30mm tubes, with UM Tikka lows and mediums.