Need some help with a couple things

[7mmfan]

I'm buying a new scope for my 7 mag. Its a Leupold VX3i 4.5-14x40 with the CDS system. I need to complete 2 tasks before I order.

1. I need to run my load through a chrono so they can set up the turrets with the correct load data.
2. I need to measure the distance from the center of the barrel to the center of the scope.

I don't have a chrono, so if anyone in the Marysville area has one and wouldn't mind meeting up with me to do a little shooting, I'd sure appreciate it.

I'm also not sure how to go about making the measurement from the barrel to the scope. Anyone have any experience with this?

[BULLBLASTER]

The sight height should be somewhere around 1.75 to 2.25 inches. I usually get this by roughly eyeballing the centerline of the bore (sometimes where the top of the forearm meets the side of the barrel) up to the centerline of the scope.

As for a chrono I'm too far away.

[Stein]

I used micrometers to get the distance between the top of the bolt and the bottom of the scope.  Then, measure the scope tube diameter and bolt diameter and a little math gives you an accurate measurement.

For a velocity, I would go to the range, shoot known distances and then calculate velocity with the online tools.  Much more accurate than any chrono you are likely to get your hands on.

[7mmfan]

I used micrometers to get the distance between the top of the bolt and the bottom of the scope.  Then, measure the scope tube diameter and bolt diameter and a little math gives you an accurate measurement.

For a velocity, I would go to the range, shoot known distances and then calculate velocity with the online tools.  Much more accurate than any chrono you are likely to get your hands on.

Explain this to me.

[JDHasty]

I used micrometers to get the distance between the top of the bolt and the bottom of the scope.  Then, measure the scope tube diameter and bolt diameter and a little math gives you an accurate measurement.

For a velocity, I would go to the range, shoot known distances and then calculate velocity with the online tools.  Much more accurate than any chrono you are likely to get your hands on.

Explain this to me.

That depends on the accuracy of your rifle and how well you can shoot it.  You use drop at various ranges to calculate velocity along the way, but that means shooting out to fairly significant range.  It is quite a process to do it right and your ranges have to be very accurately surveyed or your calculated MV will be off.u

I'm sure someone up there has an Oehler that will set it up for you and that will give you an accurate reading that will be more than reliable. 

[Reidus]

Measure outside of barrel to outside of scope and then subtract radius of scope and radius of barrel at that point. This will give you center of bore to center of scope distance.

[Reidus]

http://www.sinclairintl.com/GunTech

 

[actionshooter]

If you can come up with a magneto-speed, they can be trusted for accurate velocity.....standard chrono, not so much

for the scope height, I measure as indicated above

[7mmfan]

Alright I've got the measurement part handled, I feel dumb that I didn't figure that out myself.

I'm sure I could figure out the velocity based on bullet drop now that I see the process you're talking about. I think I'd rather just round up a chrono. Good advice though.

[BULLBLASTER]

I used micrometers to get the distance between the top of the bolt and the bottom of the scope.  Then, measure the scope tube diameter and bolt diameter and a little math gives you an accurate measurement.

For a velocity, I would go to the range, shoot known distances and then calculate velocity with the online tools.  Much more accurate than any chrono you are likely to get your hands on.

Explain this to me.

That depends on the accuracy of your rifle and how well you can shoot it.  You use drop at various ranges to calculate velocity along the way, but that means shooting out to fairly significant range.  It is quite a process to do it right and your ranges have to be very accurately surveyed or your calculated MV will be off.u

I'm sure someone up there has an Oehler that will set it up for you and that will give you an accurate reading that will be more than reliable.

Then you'd be assuming the ballistic coefficient of the bullet that is published is accurate as well.
As stated a good quality chrono will be much easier gen you can validate the trajectory at longer range.

[7mmfan]

Got a chrono arranged for this weekend with a local hunt-wa member, looks like I'm on my way. Thanks for the advice guys, I learned some stuff.