Second Focal Plane Question

[284winner]

I would agree, but no matter how sophisticated the app is, it can't be trusted unless it is verified with actual extensive shooting. Just running the numbers and trusting the accuracy of your settings is going to be frustrating. I'm afraid too many will go that route rather than spending the time and effort to test those settings before trusting them on game. Those programs or apps are tools, but they can't do the whole job for you.

I guess I've been pretty lucky. Most of my rifles have been nearly spot on based on the ballistic data I rely on prior to range work. Not perfect but it's always important to shoot the rifle. Kinda like the old days when a rifle was bore sighted at a gun shop. It still needs dialing in.

 

[Rob01]

I would agree, but no matter how sophisticated the app is, it can't be trusted unless it is verified with actual extensive shooting. Just running the numbers and trusting the accuracy of your settings is going to be frustrating. I'm afraid too many will go that route rather than spending the time and effort to test those settings before trusting them on game. Those programs or apps are tools, but they can't do the whole job for you.

Maybe. A lot of the new apps are very accurate. I use Hornady 4 Dof at matches and make first round hit to around 1400 yards. You don't have the luxury of laying down and shooting hundreds of rounds to get data at different locations around the country when you go to a match and have to use apps. You put in good data and the data you get is usually within .1 mil of what you need if not right on.

If you shoot at one place and log your data in many different environmental conditions then you can build a good data book but not an option for some.

 

[SSL]

Maybe. A lot of the new apps are very accurate. I use Hornady 4 Dof at matches and make first round hit to around 1400 yards. You don't have the luxury of laying down and shooting hundreds of rounds to get data at different locations around the country when you go to a match and have to use apps. You put in good data and the data you get is usually within .1 mil of what you need if not right on.

If you shoot at one place and log your data in many different environmental conditions then you can build a good data book but not an option for some.

I'm not criticizing the apps, in fact I think they are great if use properly. This means not just taking it for granted that XYZ load plugged into an app and tested at 100 yards is going to produce data that will be accurate at 1,000. It's like the old computer programmers' GIGA - garbage in, garbage out. If one takes the effort to enter precise, accurate information regarding loads such as measured velocity, verified BC, precise scope height and a host of other data requirements and then verify the results at least once, you get the repeatability that you describe. I've had several people complain about the accuracy of Strelok at extended range, only to find that their load shoots "about" XXX fps, and they think their scope is 1.5" above the bore, and... Well, you get my point.

 

[Rob01]

Yup ballistic programs have always been garbage in, garbage out. If you put good info in they are very accurate. Especially newer ones using Doppler.

 

[sscoyote]

Also be aware that changing magnification on a SFP scope can sometimes throw point of impact off some.

And that if it's calibrated for say 20X, that your magnification ring may not be exactly on 10X to get your 2 MOA subtension.
Much like most paralax adjustments may be off some at a given range.

I have seen some serious reticle vertex movement on some optics as magnification and parallax are changed with the use of a grid boresighter, even detached reticles when the power is changed that wouldn't have been noticed otherwise. Doesn't do much for instilling confidence with your optic when the reticle vertex moves a couple minutes between power settings.